1
00:00:00,000 --> 00:00:03,727
The following content is
provided by MIT OpenCourseWare

2
00:00:03,727 --> 00:00:06,271
under a Creative Commons
license.

3
00:00:06,271 --> 00:00:09,833
Additional information about
our license and MIT

4
00:00:09,833 --> 00:00:12,377
OpenCourseWare in general is
available at ocw.mit.edu.

5
00:00:15,430 --> 00:00:23,090
PROFESSOR: This is the lecture
on sleep and dreams, and you

6
00:00:23,090 --> 00:00:27,870
want to know about this because
it's -- well, at MIT,

7
00:00:27,870 --> 00:00:31,140
sleep and dreams is a topic that
falls under the heading

8
00:00:31,140 --> 00:00:35,030
of abnormal psychology.

9
00:00:35,030 --> 00:00:40,120
All right, let us ask to begin,
how many people here

10
00:00:40,120 --> 00:00:44,210
got some sleep last night?

11
00:00:44,210 --> 00:00:45,240
OK.

12
00:00:45,240 --> 00:00:51,020
Of those people, how many people
went to sleep, even

13
00:00:51,020 --> 00:00:54,110
though they knew they
still had stuff they

14
00:00:54,110 --> 00:00:57,140
wanted to get done?

15
00:00:57,140 --> 00:00:57,820
All right.

16
00:00:57,820 --> 00:01:01,100
So, what's your problem?

17
00:01:01,100 --> 00:01:05,380
Well, the typical MIT
answer to that is

18
00:01:05,380 --> 00:01:07,710
sort of a moral argument.

19
00:01:07,710 --> 00:01:09,270
I'm weak.

20
00:01:09,270 --> 00:01:13,420
I'm a miserable human being.

21
00:01:13,420 --> 00:01:18,100
If I was a good, strong human
being, I would not have gotten

22
00:01:18,100 --> 00:01:22,420
sleep, I would have done that
problem set and so on.

23
00:01:28,140 --> 00:01:29,440
If you were not at MIT --

24
00:01:34,040 --> 00:01:37,340
MIT is merely at one
extreme here.

25
00:01:37,340 --> 00:01:41,920
Western civilization in general
increasingly, since

26
00:01:41,920 --> 00:01:45,570
the invention of the lightbulb,
has been an

27
00:01:45,570 --> 00:01:53,190
increasingly sleep-abusing,
mechanism-abusing culture.

28
00:01:53,190 --> 00:01:56,590
But if you were left to your own
devices or to what nature

29
00:01:56,590 --> 00:01:58,820
had intended, you'd be sleeping
about eight hours a

30
00:01:58,820 --> 00:02:04,620
night, and you would be doing
this across your life span

31
00:02:04,620 --> 00:02:07,570
with the result that you would
spend about a third of your

32
00:02:07,570 --> 00:02:13,670
life asleep in this altered
state of consciousness or

33
00:02:13,670 --> 00:02:14,920
unconsciousness.

34
00:02:16,780 --> 00:02:21,420
That, if you're teaching a
course on human behavior and

35
00:02:21,420 --> 00:02:26,030
human mental life, that requires
some explanation.

36
00:02:26,030 --> 00:02:28,500
Why do people sleep?

37
00:02:28,500 --> 00:02:35,210
What is the nature of
that behavior left

38
00:02:35,210 --> 00:02:36,650
to its normal state?

39
00:02:36,650 --> 00:02:39,350
What happens when
you abuse it?

40
00:02:39,350 --> 00:02:43,960
Why do people dream, which is
psychologically, perhaps, the

41
00:02:43,960 --> 00:02:46,390
most interesting
piece of sleep.

42
00:02:46,390 --> 00:02:49,020
Is it possible to get any --

43
00:02:49,020 --> 00:02:50,750
do those dreams, do those weird

44
00:02:50,750 --> 00:02:52,400
stories have any meaning?

45
00:02:52,400 --> 00:02:54,810
Those are the questions
that I'll talk about.

46
00:02:54,810 --> 00:02:58,200
I don't know if I'll get to
end of it today, otherwise

47
00:02:58,200 --> 00:03:02,810
I'll pick up after
Thanksgiving.

48
00:03:02,810 --> 00:03:08,930
Let's talk initially about
why and how you sleep.

49
00:03:08,930 --> 00:03:11,870
Well, look, I mean one level of
answer would be you sleep

50
00:03:11,870 --> 00:03:18,630
because every so often nuclei,
collections of nerve cells

51
00:03:18,630 --> 00:03:23,940
deep down in your brain stem
send volleys of signals up to

52
00:03:23,940 --> 00:03:27,180
the rest of your brain that
basically make like a hammer

53
00:03:27,180 --> 00:03:28,970
and knock you out.

54
00:03:28,970 --> 00:03:31,420
But that's not a deeply
satisfying answer.

55
00:03:31,420 --> 00:03:37,180
It does point to the fact that
it's a very basic drive, and

56
00:03:37,180 --> 00:03:38,910
it's a very powerful drive.

57
00:03:38,910 --> 00:03:45,070
Look, if you wanted to you
could, for example, as a

58
00:03:45,070 --> 00:03:52,890
statement of extreme political
conviction, sit right here and

59
00:03:52,890 --> 00:03:55,340
starve yourself to death.

60
00:03:55,340 --> 00:03:57,590
Hunger is an important drive.

61
00:03:57,590 --> 00:03:59,686
There are several people
illustrating that

62
00:03:59,686 --> 00:04:03,100
at this very moment.

63
00:04:03,100 --> 00:04:08,380
If you wanted, you could
override that and not eat,

64
00:04:08,380 --> 00:04:11,640
even to the point of
killing yourself.

65
00:04:11,640 --> 00:04:16,560
That's not true, for example,
about your breathing.

66
00:04:16,560 --> 00:04:19,770
If you wanted to sit here and
hold your breath until you

67
00:04:19,770 --> 00:04:23,550
died, it wouldn't work.

68
00:04:23,550 --> 00:04:27,840
You may have tried this
when you were little.

69
00:04:27,840 --> 00:04:30,680
One of my two sisters used
to be a fan of this.

70
00:04:30,680 --> 00:04:33,160
If we were teasing her and
chasing her she would just

71
00:04:33,160 --> 00:04:36,750
hold her breath until she keeled
over, which was very

72
00:04:36,750 --> 00:04:41,020
dramatic, but not, in fact, life
threatening, except in

73
00:04:41,020 --> 00:04:44,010
indirect sense that my mother
was not thrilled with us

74
00:04:44,010 --> 00:04:46,090
making my little sister
pass out.

75
00:04:49,310 --> 00:04:51,455
You could ask her, she'll be
here tomorrow, but you'll all

76
00:04:51,455 --> 00:04:52,180
be leaving.

77
00:04:52,180 --> 00:05:03,863
Anyway, this drive to sleep is
more like the need to breath

78
00:05:03,863 --> 00:05:06,170
than the need to eat
in that sense.

79
00:05:06,170 --> 00:05:10,890
If you were to sit here and by
an act of will declare I will

80
00:05:10,890 --> 00:05:14,530
not fall asleep -- and look,
as you well know, there's a

81
00:05:14,530 --> 00:05:17,695
substantial number of you who
can't manage to do that for an

82
00:05:17,695 --> 00:05:19,780
hour and a half.

83
00:05:19,780 --> 00:05:21,850
That has to do with how you're
abusing the normal

84
00:05:21,850 --> 00:05:23,100
mechanism on --

85
00:05:25,410 --> 00:05:30,025
when I first was teaching, I
used to look out at 10250 full

86
00:05:30,025 --> 00:05:33,120
of intro psych students
in they're ahh.

87
00:05:33,120 --> 00:05:35,940
I'm thinking I'm not being
lively enough here.

88
00:05:35,940 --> 00:05:38,610
I realize at this point, I could
be setting off large

89
00:05:38,610 --> 00:05:41,410
explosions on a regular basis
and it wouldn't matter for

90
00:05:41,410 --> 00:05:43,050
some people.

91
00:05:43,050 --> 00:05:45,380
We'll get to that in a minute.

92
00:05:45,380 --> 00:05:52,200
But even those of you who are
well-rested, you could not sit

93
00:05:52,200 --> 00:05:53,980
here and not sleep.

94
00:05:53,980 --> 00:05:56,710
Probably you couldn't make
it for twenty-four hours.

95
00:05:56,710 --> 00:05:59,450
Absolutely you could not make
it for forty-eight hours

96
00:05:59,450 --> 00:06:05,790
without external help, either
from drugs, like caffeine, or

97
00:06:05,790 --> 00:06:08,630
more particularly from somebody
smacking you around

98
00:06:08,630 --> 00:06:09,850
to keep you awake.

99
00:06:09,850 --> 00:06:12,940
If you're in a sleep lab and
you want to keep somebody

100
00:06:12,940 --> 00:06:20,150
awake for thirty-six hours or
something to see what happens,

101
00:06:20,150 --> 00:06:23,470
you sure don't say, I'll give
you ten bucks if you can stay

102
00:06:23,470 --> 00:06:24,720
awake all night.

103
00:06:24,720 --> 00:06:28,760
You need somebody there to slap
them around and keep them

104
00:06:28,760 --> 00:06:30,500
moving or they'll be out.

105
00:06:30,500 --> 00:06:33,140
There's just no way
to suppress that.

106
00:06:33,140 --> 00:06:37,280
It's a very, very
powerful drive.

107
00:06:37,280 --> 00:06:40,350
So, how come?

108
00:06:40,350 --> 00:06:42,860
What's doing this?

109
00:06:42,860 --> 00:06:49,200
Your need to sleep is driven
by two primary factors.

110
00:06:49,200 --> 00:06:51,810
One of them is a so-called
circadian rhythm.

111
00:06:51,810 --> 00:06:55,630
The term comes from -- circadian
is about a day,

112
00:06:55,630 --> 00:06:58,650
because it's a rhythm with
a periodicity of about

113
00:06:58,650 --> 00:07:01,850
twenty-four hours.

114
00:07:01,850 --> 00:07:06,190
If you manage to measure it in
isolation, and you were to

115
00:07:06,190 --> 00:07:09,000
measure something like
alertness, it would have a

116
00:07:09,000 --> 00:07:13,410
roughly sinusoidal shape to
it, this particular drive.

117
00:07:13,410 --> 00:07:15,910
When you wake up, it's
actually at a

118
00:07:15,910 --> 00:07:18,820
relative low point.

119
00:07:18,820 --> 00:07:19,800
Yeah, right.

120
00:07:19,800 --> 00:07:23,990
At six a.m. on this chart, is
it a relative low point?

121
00:07:23,990 --> 00:07:29,550
It rises your alertness driven
by the circadian clock, rises

122
00:07:29,550 --> 00:07:33,710
systematically during the course
of the day till early

123
00:07:33,710 --> 00:07:38,390
evening, and then declines to a
nadir around four or five in

124
00:07:38,390 --> 00:07:39,140
the morning.

125
00:07:39,140 --> 00:07:43,040
When you're trying to stay up
all night, that time in the

126
00:07:43,040 --> 00:07:46,230
wee hours of the morning when
it's just really, really tough

127
00:07:46,230 --> 00:07:52,310
and you're getting the shakes
and all, is when this

128
00:07:52,310 --> 00:07:57,360
circadian clock is crashing,
is hitting its minimum.

129
00:07:57,360 --> 00:07:58,690
How do we measure this?

130
00:07:58,690 --> 00:08:00,600
How do we measure circadian
cycles?

131
00:08:00,600 --> 00:08:04,490
Well, if you're a mouse it's
actually relatively easy.

132
00:08:04,490 --> 00:08:06,860
Stick a mouse in a cage with
one of those little running

133
00:08:06,860 --> 00:08:12,890
wheels and put a sensor on the
running wheel, and you'll get

134
00:08:12,890 --> 00:08:15,600
out a graph that looks
like the graph that

135
00:08:15,600 --> 00:08:16,530
I put on the handout.

136
00:08:16,530 --> 00:08:20,400
Each of the lines on that graph
is one day, so you've

137
00:08:20,400 --> 00:08:26,060
got a day here, and the mouse
is doing nothing much.

138
00:08:26,060 --> 00:08:30,870
Then at a certain point, the
mouse jumps on the wheel and

139
00:08:30,870 --> 00:08:31,400
does stuff.

140
00:08:31,400 --> 00:08:36,340
Now, the convention of the
circadian trade is to

141
00:08:36,340 --> 00:08:37,750
double-plot their data.

142
00:08:37,750 --> 00:08:42,130
So the line is the same
data plotted twice.

143
00:08:42,130 --> 00:08:44,650
It's just makes it easier to
see trends over the day.

144
00:08:44,650 --> 00:08:48,100
So this is inactivity,
activity, same day.

145
00:08:51,750 --> 00:08:55,200
This is twenty-four hours.

146
00:08:55,200 --> 00:09:06,113
You can see that the mouse does
this every day, for day

147
00:09:06,113 --> 00:09:10,600
after day, like clockwork, as it
were, because the mouse has

148
00:09:10,600 --> 00:09:12,200
this little clock that's
telling it.

149
00:09:12,200 --> 00:09:18,630
Now, the point at which the
mouse is firing things up,

150
00:09:18,630 --> 00:09:23,540
right about here, is the mouse
was on a twelve hour

151
00:09:23,540 --> 00:09:25,500
light/dark schedule, and
when the lights go out,

152
00:09:25,500 --> 00:09:26,760
the mouse turns on.

153
00:09:26,760 --> 00:09:28,870
It's a nocturnal beastie.

154
00:09:28,870 --> 00:09:30,420
When the lights go out
he jumps on the

155
00:09:30,420 --> 00:09:32,360
wheel and goes berserk.

156
00:09:32,360 --> 00:09:37,280
Now, what happens halfway down
that graph where there's an

157
00:09:37,280 --> 00:09:41,520
arrow pointing at the side of
the data, at that point you

158
00:09:41,520 --> 00:09:44,180
leave the lights on
continuously.

159
00:09:44,180 --> 00:09:50,360
What you discover is the mouse
still behaves in a very

160
00:09:50,360 --> 00:09:51,270
systematic fashion.

161
00:09:51,270 --> 00:09:53,550
I'm not going to bother
double-plotting my data

162
00:09:53,550 --> 00:09:55,270
anymore here.

163
00:09:55,270 --> 00:10:02,830
But now the period is
starting to drift.

164
00:10:02,830 --> 00:10:06,510
The mouse is now doing what's
known as free-running, and

165
00:10:06,510 --> 00:10:09,820
this is a way that you can take
a look at the circadian

166
00:10:09,820 --> 00:10:16,110
cycle in this beastie because
he's now no longer got the

167
00:10:16,110 --> 00:10:19,440
light signal telling him
what time it is.

168
00:10:19,440 --> 00:10:22,890
What you discover is that it's
advancing by about thirty

169
00:10:22,890 --> 00:10:28,520
minutes a day, because the mouse
clock has a period, a

170
00:10:28,520 --> 00:10:30,690
circadian period of about
twenty-three and

171
00:10:30,690 --> 00:10:32,400
a half hours --

172
00:10:32,400 --> 00:10:35,610
not quite twenty-four hours.

173
00:10:35,610 --> 00:10:38,600
If you were in the same
experiment and you were

174
00:10:38,600 --> 00:10:42,470
inclined to run around in a
wheel, the day would actually

175
00:10:42,470 --> 00:10:46,490
go this way a little bit,
because the human clock has a

176
00:10:46,490 --> 00:10:50,020
period of about twenty-four and
a quarter to twenty-four

177
00:10:50,020 --> 00:10:51,920
and a half hours,
some variation.

178
00:10:51,920 --> 00:10:55,330
It's again, around a day.

179
00:10:55,330 --> 00:11:01,150
It gets synchronized
to the real day

180
00:11:01,150 --> 00:11:03,820
by light most strongly.

181
00:11:03,820 --> 00:11:07,200
So you know when it's morning
because that's when

182
00:11:07,200 --> 00:11:08,800
the sun comes up.

183
00:11:08,800 --> 00:11:11,790
If you never get outside and
you live in constant light,

184
00:11:11,790 --> 00:11:14,960
your clock may be drifting
too in something fashion.

185
00:11:14,960 --> 00:11:18,990
But given a normal exposure
to light/dark cycles,

186
00:11:18,990 --> 00:11:20,800
that sets the clock.

187
00:11:20,800 --> 00:11:23,030
How many people are flying
across time zones to

188
00:11:23,030 --> 00:11:25,330
the next few days?

189
00:11:25,330 --> 00:11:29,260
So you guys are all going to be
jet lagged in some fashion,

190
00:11:29,260 --> 00:11:33,570
because your clock is set for
East coast, U.S., you'll go

191
00:11:33,570 --> 00:11:35,800
someplace else.

192
00:11:35,800 --> 00:11:38,700
Get outside because it's
exposure to the sun

193
00:11:38,700 --> 00:11:40,930
that will reset you.

194
00:11:40,930 --> 00:11:43,050
Exposure to these sort of lights
will reset you too, but

195
00:11:43,050 --> 00:11:47,780
the sun is sufficiently brighter
that it makes a

196
00:11:47,780 --> 00:11:49,130
bigger difference.

197
00:11:49,130 --> 00:11:52,480
This clock, by the
way, has a home.

198
00:11:52,480 --> 00:12:05,530
It's located in the
suprachiasmatic nucleus.

199
00:12:05,530 --> 00:12:07,420
Looks more complicated
than it is.

200
00:12:07,420 --> 00:12:10,180
Supra for above.

201
00:12:10,180 --> 00:12:16,180
Chiasmatic for the optic chiasm,
that x where the optic

202
00:12:16,180 --> 00:12:21,560
nerves cross on the way from
the eyes to the brain.

203
00:12:21,560 --> 00:12:24,790
This sits right on top of
that and gets direct

204
00:12:24,790 --> 00:12:25,780
input from the retina.

205
00:12:25,780 --> 00:12:29,840
It's got its own visual
system in a sense.

206
00:12:29,840 --> 00:12:33,602
How do we know that this is
where the clock lives?

207
00:12:33,602 --> 00:12:34,640
There are a number of ways.

208
00:12:34,640 --> 00:12:37,000
But the coolest way that we know
that this is where the

209
00:12:37,000 --> 00:12:43,270
clock lives is that there are
clock mutants out there,

210
00:12:43,270 --> 00:12:46,670
probably some human, but
certainly mouse mutants.

211
00:12:46,670 --> 00:12:50,570
Suppose you got a mouse mutant
who, let's say, has a clock

212
00:12:50,570 --> 00:12:55,130
running at, say, twenty-two
hours or something like that.

213
00:12:55,130 --> 00:12:59,250
You can go in, take out the
suprachiasmatic nucleus from

214
00:12:59,250 --> 00:13:03,720
that mouse, put it into another
mouse -- and this is a

215
00:13:03,720 --> 00:13:06,720
case where a brain transplant
will actually work.

216
00:13:06,720 --> 00:13:11,080
The recipient mouse will now
start running with the clock

217
00:13:11,080 --> 00:13:15,420
timing of the donor mouse.

218
00:13:15,420 --> 00:13:19,180
If you want a new clock, you
can actually go and get --

219
00:13:19,180 --> 00:13:23,030
I don't know if you go and get
one from a mouse, and probably

220
00:13:23,030 --> 00:13:24,940
your neighbor doesn't
want to donate.

221
00:13:28,110 --> 00:13:30,650
There are also other clocks,
by the way, that live in

222
00:13:30,650 --> 00:13:33,770
places like your liver, but the
main clock running your

223
00:13:33,770 --> 00:13:39,650
behavior is sitting up there
in your brain and reset by

224
00:13:39,650 --> 00:13:45,660
light, and in fact, can be
transplanted, apparently.

225
00:13:45,660 --> 00:13:50,940
Now, humans don't tend
to run in little

226
00:13:50,940 --> 00:13:54,390
mouse wheels very much.

227
00:13:54,390 --> 00:13:59,980
If you want to measure this in
a human, if you stick a human

228
00:13:59,980 --> 00:14:06,220
in continuous light, and cut
them off from the external

229
00:14:06,220 --> 00:14:08,465
world, which you can
get yourself paid

230
00:14:08,465 --> 00:14:09,830
to do if you want.

231
00:14:09,830 --> 00:14:14,570
One of the leading sleep labs
in the world, actually, is

232
00:14:14,570 --> 00:14:17,120
across the river at Brigham
and Women's.

233
00:14:17,120 --> 00:14:20,710
My lab actually does some
collaborating with them.

234
00:14:20,710 --> 00:14:22,550
So if you're interested
talk to me.

235
00:14:22,550 --> 00:14:23,985
People do this as
a summer job.

236
00:14:23,985 --> 00:14:28,390
You get locked in the
lab for the summer.

237
00:14:28,390 --> 00:14:30,605
People think oh, I'm going to
write the great American novel

238
00:14:30,605 --> 00:14:32,530
or something like that
while I stay up

239
00:14:32,530 --> 00:14:34,390
all night or something.

240
00:14:34,390 --> 00:14:36,780
But you get paid a decent
rate for this.

241
00:14:42,060 --> 00:14:44,360
Now we're going to want to
keep track of what your

242
00:14:44,360 --> 00:14:47,020
circadian clock is doing.

243
00:14:47,020 --> 00:14:50,430
The sorts of things that vary
with your clock are, for

244
00:14:50,430 --> 00:14:53,740
example, body temperature.

245
00:14:53,740 --> 00:14:57,320
Your body temperature has about
a one degree plus and

246
00:14:57,320 --> 00:15:01,830
minus swing with the
circadian clock.

247
00:15:01,830 --> 00:15:05,510
So, if you've got a fever, for
example, you'd probably

248
00:15:05,510 --> 00:15:07,760
remember from when you were a
little kid that your fever

249
00:15:07,760 --> 00:15:10,390
would peak in the
early evening.

250
00:15:10,390 --> 00:15:12,900
If you stay up all night it's
four in the morning where you

251
00:15:12,900 --> 00:15:14,450
suddenly feel chilled.

252
00:15:14,450 --> 00:15:16,610
That's because your body
temperature is actually

253
00:15:16,610 --> 00:15:19,580
varying as a function of
the circadian cycle.

254
00:15:19,580 --> 00:15:23,815
There are lots of circulating
hormones, like melatonin and

255
00:15:23,815 --> 00:15:27,430
others, in the blood that also
track the circadian clock.

256
00:15:27,430 --> 00:15:32,570
So, if you're in the lab,
somebody is going to be

257
00:15:32,570 --> 00:15:36,180
monitoring these various aspects
of your physiology in

258
00:15:36,180 --> 00:15:39,460
an effort to take a look at
where your circadian clock is.

259
00:15:39,460 --> 00:15:41,850
This is one of the things that
sort of discourages people

260
00:15:41,850 --> 00:15:45,730
from immediately signing up,
because well, for instance, if

261
00:15:45,730 --> 00:15:47,830
you're going to be taking
continuous measures of body

262
00:15:47,830 --> 00:15:50,220
temperature, the thermometer
is not under your tongue.

263
00:15:54,970 --> 00:15:59,450
It's a slow group.

264
00:15:59,450 --> 00:16:10,650
Anyway, so you got the circadian
clock that's driving

265
00:16:10,650 --> 00:16:13,590
your alertness.

266
00:16:13,590 --> 00:16:17,730
The other piece that's driving
you're alertness, or inversely

267
00:16:17,730 --> 00:16:23,370
this powerful drive to sleep, is
sometimes called the sleep

268
00:16:23,370 --> 00:16:23,860
homeostatic.

269
00:16:23,860 --> 00:16:26,790
It's simply a homeostatic
mechanism that says the longer

270
00:16:26,790 --> 00:16:31,300
you're awake, the more
tired you get.

271
00:16:31,300 --> 00:16:34,200
This is not a huge surprise.

272
00:16:34,200 --> 00:16:35,680
So we can graph that here.

273
00:16:35,680 --> 00:16:37,590
So this again, alertness.

274
00:16:37,590 --> 00:16:40,940
Let's say this is 6:00 a.m.
again, now let's say that you

275
00:16:40,940 --> 00:16:44,200
wake up at something like 8:00,
and basically it's a

276
00:16:44,200 --> 00:16:48,880
roughly linear function of
during the day you get

277
00:16:48,880 --> 00:16:50,610
sleepier and sleepier and
sleepier and sleepier, and

278
00:16:50,610 --> 00:16:51,770
sleepier, and sleepier.

279
00:16:51,770 --> 00:16:53,530
This thing builds up
pressure to sleep.

280
00:16:53,530 --> 00:16:54,950
If you now go to sleep at let's

281
00:16:54,950 --> 00:16:57,140
say 11:00, that recovers.

282
00:16:57,140 --> 00:17:02,250
It recovers at least initially
rather steeply, and then

283
00:17:02,250 --> 00:17:04,170
probably has a sort of
an exponential tail.

284
00:17:04,170 --> 00:17:09,070
It's not absolutely clear.

285
00:17:09,070 --> 00:17:15,460
But if you combine these two,
well, if you were to combine

286
00:17:15,460 --> 00:17:20,740
these two in the way that nature
intended, what you get

287
00:17:20,740 --> 00:17:25,930
is a sustained period of --

288
00:17:25,930 --> 00:17:27,220
let's look at the course
of the day.

289
00:17:27,220 --> 00:17:33,360
Suppose you wake up in the
relatively early morning, your

290
00:17:33,360 --> 00:17:39,510
circadian clock is relatively
depressed, so it's still

291
00:17:39,510 --> 00:17:41,170
feeling kind of sleepy.

292
00:17:41,170 --> 00:17:46,680
But you're homeostat is fully
refreshed, so you're up here,

293
00:17:46,680 --> 00:17:49,870
let's say, in alertness land.

294
00:17:49,870 --> 00:17:54,460
Now as the homeostat is going
down, the circadian

295
00:17:54,460 --> 00:17:56,390
chunk is going up.

296
00:17:56,390 --> 00:17:59,890
So for a sustained period of
the day, say till early

297
00:17:59,890 --> 00:18:04,270
evening, you have roughly
level alertness.

298
00:18:04,270 --> 00:18:07,725
Believe it or not, that's what
really happens to people who

299
00:18:07,725 --> 00:18:08,610
are well-rested.

300
00:18:08,610 --> 00:18:11,350
They are awake during the day.

301
00:18:13,850 --> 00:18:24,640
Some time in early evening when
the circadian clock turns

302
00:18:24,640 --> 00:18:28,430
downward, things start going
downhill for you and your

303
00:18:28,430 --> 00:18:32,720
alertness starts steadily
dropping.

304
00:18:32,720 --> 00:18:38,623
At some point it drops enough
that you -- well, that people

305
00:18:38,623 --> 00:18:41,930
who are not abusing
the system --

306
00:18:41,930 --> 00:18:43,250
go to sleep.

307
00:18:47,230 --> 00:18:52,900
So now, you're asleep so you're
not terribly alert.

308
00:18:52,900 --> 00:18:56,240
So what's happening now is, so
you're down here in asleep

309
00:18:56,240 --> 00:18:59,210
land somewhere, now
your homeostat

310
00:18:59,210 --> 00:19:01,270
is recovering, right?

311
00:19:01,270 --> 00:19:05,110
But in the early portions of
your sleep, or during the

312
00:19:05,110 --> 00:19:07,150
course of the night, this
circadian thing is still

313
00:19:07,150 --> 00:19:08,420
crashing down.

314
00:19:08,420 --> 00:19:12,610
So even though you may have
climbed up here already on the

315
00:19:12,610 --> 00:19:17,390
homeostat, you're crashing down
to here and the circadian

316
00:19:17,390 --> 00:19:20,110
thing is saying stay asleep,
stay asleep,

317
00:19:20,110 --> 00:19:21,294
it's good for you.

318
00:19:21,294 --> 00:19:26,370
You should be asleep for this
sustained eight hours.

319
00:19:26,370 --> 00:19:32,380
Then it turns around in the
early morning hours and 4:00,

320
00:19:32,380 --> 00:19:33,440
5:00, 6:00 a.m.

321
00:19:33,440 --> 00:19:36,940
you wake with the chickens and
you're bright and perky and

322
00:19:36,940 --> 00:19:40,600
alert, like you are
every morning.

323
00:19:40,600 --> 00:19:41,150
You're back.

324
00:19:41,150 --> 00:19:44,380
So what you get out of this
system, if it's being allowed

325
00:19:44,380 --> 00:19:49,690
to work properly, is a sustained
period of alertness

326
00:19:49,690 --> 00:19:52,570
during the day, and the
sustained bout of

327
00:19:52,570 --> 00:19:53,650
sleep during the night.

328
00:19:53,650 --> 00:19:59,940
If you crash the circadian
system, for instance, you end

329
00:19:59,940 --> 00:20:03,930
up with broken sleep.

330
00:20:03,930 --> 00:20:10,210
So, you blow up a mouse's
circadian clock, and what you

331
00:20:10,210 --> 00:20:13,600
get is a mouse who runs and
naps, and runs and naps, and

332
00:20:13,600 --> 00:20:19,470
runs and naps -- doesn't have
this organized pattern to it.

333
00:20:19,470 --> 00:20:24,440
Now, the great tragedy, of
course, is that you guys who

334
00:20:24,440 --> 00:20:28,850
are in the peak of your
ability to do this

335
00:20:28,850 --> 00:20:31,120
aren't doing it.

336
00:20:31,120 --> 00:20:34,730
You're abusing the
pants off it.

337
00:20:34,730 --> 00:20:37,810
The structure of sleep
changes over the

338
00:20:37,810 --> 00:20:40,730
course of the lifespan.

339
00:20:40,730 --> 00:20:45,780
Babies sleep for a lot longer
than adults do.

340
00:20:45,780 --> 00:20:50,220
After early childhood, people
have a fairly constant

341
00:20:50,220 --> 00:20:52,290
requirement for about
eight hours.

342
00:20:52,290 --> 00:20:55,480
The range is really about
seven to nine hours.

343
00:20:55,480 --> 00:21:01,610
People who say they require only
four hours of sleep or

344
00:21:01,610 --> 00:21:04,110
something like that are
basically lying to you.

345
00:21:06,850 --> 00:21:10,010
Thomas Edison, right, he's
always trotted out as the

346
00:21:10,010 --> 00:21:10,900
example here.

347
00:21:10,900 --> 00:21:12,860
I don't remember what he needed,
two hours a night,

348
00:21:12,860 --> 00:21:13,560
four hours a night.

349
00:21:13,560 --> 00:21:17,000
Well, there was a reason the
man had a cot in is office.

350
00:21:17,000 --> 00:21:20,380
The people who don't sleep
eight hours at night are

351
00:21:20,380 --> 00:21:22,770
catching naps when they can
and they're building up a

352
00:21:22,770 --> 00:21:26,200
sleep debt the rest
of the time.

353
00:21:26,200 --> 00:21:27,850
The sleep debt is --

354
00:21:27,850 --> 00:21:37,520
if you are Dement, William
Dement, Stanford sleep

355
00:21:37,520 --> 00:21:41,390
researcher coined the term sleep
debt, I think, argues

356
00:21:41,390 --> 00:21:43,360
that it may be the biggest
health problem in

357
00:21:43,360 --> 00:21:44,820
the U.S. Why is that?

358
00:21:44,820 --> 00:21:47,760
Well because all sorts of stuff
from traffic accidents

359
00:21:47,760 --> 00:21:54,290
to industrial accidents and so
on, occur basically in the wee

360
00:21:54,290 --> 00:21:57,850
hours of the morning when the
circadian clock is busy

361
00:21:57,850 --> 00:22:03,600
crashing, because sleepiness is
not good for behavior, as

362
00:22:03,600 --> 00:22:07,210
you may have noticed in various
and sundry ways.

363
00:22:07,210 --> 00:22:11,490
When you get older, it turns
out to get harder -- for

364
00:22:11,490 --> 00:22:13,910
reasons we don't really
understand -- to maintain this

365
00:22:13,910 --> 00:22:16,240
consolidated period of sleep.

366
00:22:16,240 --> 00:22:22,690
So, it is a sad fact that I, for
instance, do not typically

367
00:22:22,690 --> 00:22:26,490
manage to sleep eight hours
solidly, anything like eight

368
00:22:26,490 --> 00:22:31,330
hours solidly, at a stretch
anymore, even though I have

369
00:22:31,330 --> 00:22:35,470
long ago abandoned my various
efforts to abuse the system.

370
00:22:35,470 --> 00:22:37,720
I'd love to sleep a solid
twelve, seven

371
00:22:37,720 --> 00:22:39,260
would be happy enough.

372
00:22:39,260 --> 00:22:42,160
But as you get older it's
harder to maintain it.

373
00:22:42,160 --> 00:22:44,910
You can do it now and
you're not doing it.

374
00:22:44,910 --> 00:22:46,770
It's so sad.

375
00:22:46,770 --> 00:22:49,870
So, what are you doing and
why are you so deluded?

376
00:22:49,870 --> 00:22:54,590
Well, in part you're being
deluded by this circadian

377
00:22:54,590 --> 00:22:57,780
clock, because what happens?

378
00:22:57,780 --> 00:23:00,370
You stay up all night, right.

379
00:23:00,370 --> 00:23:02,340
So, where should we plot this?

380
00:23:02,340 --> 00:23:03,590
What we don't have any colors.

381
00:23:08,740 --> 00:23:12,090
Let's assume that you were once
well-rested like before

382
00:23:12,090 --> 00:23:15,630
you arrived at MIT
or something, and

383
00:23:15,630 --> 00:23:19,160
you stay up all night.

384
00:23:19,160 --> 00:23:21,770
So you were doing fine till
here and now you're

385
00:23:21,770 --> 00:23:24,010
going to stay up.

386
00:23:24,010 --> 00:23:26,620
I'm getting sleepier here.

387
00:23:26,620 --> 00:23:30,290
Well, there's the coffee
and the Jolt cola.

388
00:23:34,140 --> 00:23:36,580
Who knows what else smacking
you around.

389
00:23:36,580 --> 00:23:38,690
Stuff happens.

390
00:23:38,690 --> 00:23:42,210
But you know, you're fighting
a losing battle here.

391
00:23:42,210 --> 00:23:46,310
At 4:00 in the morning and
you're barely holding on, and

392
00:23:46,310 --> 00:23:49,560
let me tell you that psych paper
that you're writing at

393
00:23:49,560 --> 00:23:51,590
that point is not
your best work.

394
00:23:54,140 --> 00:23:55,700
So there goes 4:00
in the morning.

395
00:23:55,700 --> 00:23:59,670
But 6:00, 7:00 in the morning,
you've been up all night.

396
00:23:59,670 --> 00:24:00,490
What happens?

397
00:24:00,490 --> 00:24:04,310
The circadian clock
turns around.

398
00:24:04,310 --> 00:24:11,230
I did it, I did it, I don't need
your sleep, I'm so good.

399
00:24:11,230 --> 00:24:12,970
I'm a real MIT student!

400
00:24:12,970 --> 00:24:19,460
This is great, but
it's all fake.

401
00:24:19,460 --> 00:24:21,690
You think you're getting back
up here, forget it.

402
00:24:21,690 --> 00:24:22,820
You're in here somewhere.

403
00:24:22,820 --> 00:24:24,420
Klunk, like that.

404
00:24:27,500 --> 00:24:31,480
So you're ambling around
in this business.

405
00:24:31,480 --> 00:24:36,660
If you think that this is
great evidence that I'm

406
00:24:36,660 --> 00:24:39,270
superman and I don't
need to sleep, try

407
00:24:39,270 --> 00:24:41,140
it the second night.

408
00:24:41,140 --> 00:24:43,950
I don't know how many of you
have ever tried staying awake

409
00:24:43,950 --> 00:24:44,590
two nights.

410
00:24:44,590 --> 00:24:49,580
The way to stay awake two nights
in a row is to have

411
00:24:49,580 --> 00:24:53,870
somebody shooting at you.

412
00:24:53,870 --> 00:24:58,660
Leading funders of sleep
research are Army and

413
00:24:58,660 --> 00:25:01,890
Airforce, and they have a very
particular interest.

414
00:25:01,890 --> 00:25:03,330
Their interest is -- well, they

415
00:25:03,330 --> 00:25:04,400
have sort of two interests.

416
00:25:04,400 --> 00:25:08,530
One of the army interests is
we're going to take over this

417
00:25:08,530 --> 00:25:11,120
country in a hundred hours
straight and our boys ain't

418
00:25:11,120 --> 00:25:14,930
going to sleep until it's done,
and we don't want any

419
00:25:14,930 --> 00:25:18,070
ill effects of this.

420
00:25:18,070 --> 00:25:19,805
Got some good drugs for
us, we need drugs,

421
00:25:19,805 --> 00:25:21,470
we want good drugs.

422
00:25:21,470 --> 00:25:23,730
That's for the Army
research program.

423
00:25:23,730 --> 00:25:27,760
The Airforce says, we can fly at
night, this is cool, we've

424
00:25:27,760 --> 00:25:30,610
got really cool toys,
we can fly at night.

425
00:25:30,610 --> 00:25:34,350
It's really bad when the
helicopter guy falls asleep,

426
00:25:34,350 --> 00:25:39,170
so we need him to stay
awake at bad times.

427
00:25:39,170 --> 00:25:43,580
So they're big time funders
of this kind of stuff.

428
00:25:43,580 --> 00:25:49,000
It is the fact that the sort of
thing -- your general level

429
00:25:49,000 --> 00:25:53,510
of arousal will keep you up, and
so the panicked sense that

430
00:25:53,510 --> 00:25:55,480
you're going to flunk psych if
you don't finish the paper

431
00:25:55,480 --> 00:25:57,140
will do some good.

432
00:25:57,140 --> 00:25:59,560
The panicked sense that if you
fall asleep somebody's going

433
00:25:59,560 --> 00:26:03,220
to shoot you does
a lot of good.

434
00:26:03,220 --> 00:26:08,250
You can stay awake for a long
time under that basis.

435
00:26:08,250 --> 00:26:12,220
But it's not that you
miraculously if you just can

436
00:26:12,220 --> 00:26:15,020
make it past here you
get back up here.

437
00:26:17,530 --> 00:26:20,040
This thing, if you don't
keep recovering,

438
00:26:20,040 --> 00:26:21,340
it just keeps going.

439
00:26:25,420 --> 00:26:27,900
Eventually you're going
to fall asleep.

440
00:26:27,900 --> 00:26:33,390
It's just going to
happen to you.

441
00:26:33,390 --> 00:26:38,810
So that's the broad sort
of twenty-four

442
00:26:38,810 --> 00:26:41,800
hour scale of sleep.

443
00:26:41,800 --> 00:26:48,670
Within that, there's a structure
on top of that.

444
00:26:48,670 --> 00:26:55,550
This is sort of a ninety minute
ripple sitting on top

445
00:26:55,550 --> 00:27:01,150
of this circadian clock
that runs all day and

446
00:27:01,150 --> 00:27:02,220
while you're asleep.

447
00:27:02,220 --> 00:27:07,840
You know this during the day
by the variations -- what

448
00:27:07,840 --> 00:27:10,610
would you may have noticed were
reliable fluctuations in

449
00:27:10,610 --> 00:27:13,960
your own alertness
during the day.

450
00:27:13,960 --> 00:27:18,170
In fact, you can probably
do this --

451
00:27:18,170 --> 00:27:20,630
I should collect data
on this some year.

452
00:27:20,630 --> 00:27:23,030
I'll have to make up a
little questionnaire.

453
00:27:23,030 --> 00:27:26,000
The clock is about ninety
minutes, this lecture's about

454
00:27:26,000 --> 00:27:27,990
ninety minutes.

455
00:27:27,990 --> 00:27:34,610
So sometime during this lecture,
you'll hit the nadir

456
00:27:34,610 --> 00:27:37,080
of that ninety minute cycle.

457
00:27:37,080 --> 00:27:41,320
Actually, I can at least
ask a general question.

458
00:27:41,320 --> 00:27:45,140
How many people think they could
identify within plus or

459
00:27:45,140 --> 00:27:49,040
minus fifteen minutes the point
during an average intro

460
00:27:49,040 --> 00:27:52,790
psych lecture where they're
going, if they're going to

461
00:27:52,790 --> 00:27:54,270
lose is, where are they
going to lose it?

462
00:27:57,530 --> 00:28:01,320
Many of us know that there
are just chunks of

463
00:28:01,320 --> 00:28:03,770
time that are bad.

464
00:28:03,770 --> 00:28:06,160
You might notice, if you check
out, if you were to

465
00:28:06,160 --> 00:28:08,750
systematically survey those
during the course of the day,

466
00:28:08,750 --> 00:28:10,710
of course, it interacts with
things like when you eat your

467
00:28:10,710 --> 00:28:12,920
meals, when you get up, whether
you ever got to sleep

468
00:28:12,920 --> 00:28:15,550
last night and things like that,
but you may be able to

469
00:28:15,550 --> 00:28:19,530
peg a series of these spaced out
at ninety minutes or maybe

470
00:28:19,530 --> 00:28:24,000
180 minutes during the
course of the day.

471
00:28:24,000 --> 00:28:26,360
You see these at night, too.

472
00:28:36,420 --> 00:28:39,690
To talk about that let's fill
out this cute little chart on

473
00:28:39,690 --> 00:28:41,000
the handout.

474
00:28:44,740 --> 00:28:47,930
If I just stick a bunch of
electrodes on your head and

475
00:28:47,930 --> 00:28:50,970
record the electroencephalogram
the mass

476
00:28:50,970 --> 00:28:58,770
potentials off of billions of
neurons in your brain, what I

477
00:28:58,770 --> 00:29:05,810
will see grossly is high
frequency, low amplitude stuff

478
00:29:05,810 --> 00:29:07,770
while you are awake.

479
00:29:07,770 --> 00:29:12,160
So this is EEG.

480
00:29:12,160 --> 00:29:16,240
Depending on where I put my
electrode in the brain -- on

481
00:29:16,240 --> 00:29:18,320
the scalp, rather, I can get
a lot of other interesting

482
00:29:18,320 --> 00:29:19,480
information out of it.

483
00:29:19,480 --> 00:29:21,640
But for present purposes the
important thing is that the

484
00:29:21,640 --> 00:29:25,320
mass activity of the brain is
relatively high frequency, low

485
00:29:25,320 --> 00:29:28,650
amplitude stuff.

486
00:29:28,650 --> 00:29:35,870
If I now take a look at you when
you are deeply asleep,

487
00:29:35,870 --> 00:29:42,460
what I will find is low
frequency, high amplitude

488
00:29:42,460 --> 00:29:50,220
waves, roughly corresponding
to --

489
00:29:50,220 --> 00:29:54,490
what's going on is in deep
sleep, large bodies of neurons

490
00:29:54,490 --> 00:29:56,860
are firing together --

491
00:29:56,860 --> 00:29:59,515
everybody's on then
everybody's off.

492
00:29:59,515 --> 00:30:04,760
If you're woken up out of that
state, that's the I don't know

493
00:30:04,760 --> 00:30:08,110
where I am kind of state.

494
00:30:08,110 --> 00:30:12,210
You're deeply asleep here.

495
00:30:12,210 --> 00:30:15,110
The interesting thing,
discovered now about fifty

496
00:30:15,110 --> 00:30:24,000
years ago, is that every ninety
minutes or so you'll go

497
00:30:24,000 --> 00:30:27,200
into what we will call Rapid Eye
Movement sleep for reasons

498
00:30:27,200 --> 00:30:31,610
that will be apparently in the
next line of this table, where

499
00:30:31,610 --> 00:30:37,430
all of a sudden the brain goes
back to this high frequency,

500
00:30:37,430 --> 00:30:41,270
low amplitude kind of signal.

501
00:30:41,270 --> 00:30:44,811
Now, research over the course
of the fifty years makes it

502
00:30:44,811 --> 00:30:47,600
clear this is not exactly the
same as this, but it certainly

503
00:30:47,600 --> 00:30:50,770
looks awake-like.

504
00:30:50,770 --> 00:30:52,810
So the person is still
clearly asleep.

505
00:30:52,810 --> 00:30:55,370
The interesting thing is if you
wake somebody up out of

506
00:30:55,370 --> 00:30:58,820
this state, they will reliably
report that they are dreaming.

507
00:30:58,820 --> 00:31:00,710
Not all the time.

508
00:31:00,710 --> 00:31:03,630
If you wake people up out of
this state, they will reliably

509
00:31:03,630 --> 00:31:05,310
report that they are
not dreaming.

510
00:31:05,310 --> 00:31:07,990
Again, not all the time.

511
00:31:07,990 --> 00:31:09,780
It's not a perfect divide.

512
00:31:09,780 --> 00:31:12,560
But lots of narrative
dreaming here.

513
00:31:12,560 --> 00:31:15,220
Here you tend to get if you wake
people up and say what

514
00:31:15,220 --> 00:31:19,140
was going on, you might get an
isolated thought or some idea

515
00:31:19,140 --> 00:31:22,470
that was rattling around, but
you won't get that I was

516
00:31:22,470 --> 00:31:24,940
flying naked through the
infinite corridor with a panda

517
00:31:24,940 --> 00:31:27,680
on my back or something.

518
00:31:27,680 --> 00:31:29,160
We'll talk about that later.

519
00:31:34,360 --> 00:31:42,730
This is the nighttime
manifestation of that ninety

520
00:31:42,730 --> 00:31:46,410
minute cycle that you also
see running during the

521
00:31:46,410 --> 00:31:47,400
course of the day.

522
00:31:47,400 --> 00:31:50,160
You can pick that up in the
movements of the eyes, too.

523
00:31:50,160 --> 00:31:52,960
That's the electro-oculogram.

524
00:31:52,960 --> 00:32:04,480
While you are awake, your eyes
move ballistically to the left

525
00:32:04,480 --> 00:32:05,220
and to the right.

526
00:32:05,220 --> 00:32:09,120
Your eyes are sitting in one
place then jumping someplace

527
00:32:09,120 --> 00:32:11,690
else and moving around
like so.

528
00:32:11,690 --> 00:32:15,270
The two eyes are moving
together, so-called consensual

529
00:32:15,270 --> 00:32:17,680
eye movement.

530
00:32:17,680 --> 00:32:23,090
In deep sleep, those ballistic
movements, called saccades,

531
00:32:23,090 --> 00:32:27,980
disappear and the consensual
movements are damped down to

532
00:32:27,980 --> 00:32:32,060
so the eyes are kind of rolling
around in your head

533
00:32:32,060 --> 00:32:35,630
and they're not necessarily
rolling in that same place.

534
00:32:38,700 --> 00:32:42,340
When you go into Rapid Eye
Movement sleep, the reason it

535
00:32:42,340 --> 00:32:44,870
was called Rapid Eye Movement
sleep, it's the eyes look like

536
00:32:44,870 --> 00:32:46,190
they're awake again.

537
00:32:46,190 --> 00:32:49,950
So again, ballistically jumping

538
00:32:49,950 --> 00:32:54,330
around and jumping together.

539
00:32:54,330 --> 00:32:57,850
Is the pattern of eye movements
related to what's

540
00:32:57,850 --> 00:33:00,450
going on in your dream?

541
00:33:00,450 --> 00:33:02,680
Well, there's anecdotal evidence
for it, but if you

542
00:33:02,680 --> 00:33:05,440
think about it it's very
difficult to do the experiment

543
00:33:05,440 --> 00:33:08,340
in any terribly meaningful --

544
00:33:08,340 --> 00:33:11,810
actually there's some
interesting data in animals at

545
00:33:11,810 --> 00:33:13,780
this point.

546
00:33:13,780 --> 00:33:17,190
In any case, the eyes look
like they're awake here.

547
00:33:17,190 --> 00:33:20,500
The eyes, they're doing the
same thing that they were

548
00:33:20,500 --> 00:33:22,560
doing when they were awake.

549
00:33:22,560 --> 00:33:28,320
You can see this in your
roommate, particularly if your

550
00:33:28,320 --> 00:33:32,840
roommate has relatively
thin lids.

551
00:33:32,840 --> 00:33:36,210
You can often see the eyes
moving around under the lids,

552
00:33:36,210 --> 00:33:40,280
and if you watch your sleeping
roommate, your sleeping

553
00:33:40,280 --> 00:33:42,820
roommate may think you're
a weirdo when he

554
00:33:42,820 --> 00:33:43,600
or she wakes up.

555
00:33:43,600 --> 00:33:46,200
But you can actually see
the eyes jerking

556
00:33:46,200 --> 00:33:50,760
around under the lids.

557
00:33:54,280 --> 00:33:57,780
If you have an unusual roommate
who sleeps with the

558
00:33:57,780 --> 00:33:59,590
eyes open --

559
00:33:59,590 --> 00:34:01,280
this actually happens.

560
00:34:01,280 --> 00:34:05,040
The reason for sleeping with
your eyes closed has

561
00:34:05,040 --> 00:34:06,970
less to do with --

562
00:34:06,970 --> 00:34:09,480
it presumably has something to
do with cutting the light out,

563
00:34:09,480 --> 00:34:12,910
but it had mostly to do with
keeping the cornea hydrated,

564
00:34:12,910 --> 00:34:15,700
keeping it moist while
you're asleep.

565
00:34:15,700 --> 00:34:19,180
If you sleep with your eyes
open, you wake up with nasty,

566
00:34:19,180 --> 00:34:21,160
scratchy, itchy eyeballs.

567
00:34:21,160 --> 00:34:23,230
Because if you think about
it, you don't sleep

568
00:34:23,230 --> 00:34:25,090
with your ears closed.

569
00:34:25,090 --> 00:34:29,900
It's perfectly possible to use
your brain in some fashion to

570
00:34:29,900 --> 00:34:33,530
shut off enough of the ambient
outside stimulus to go to

571
00:34:33,530 --> 00:34:36,190
sleep to get rid of the
auditory stimulus.

572
00:34:36,190 --> 00:34:39,390
So, in principle, you can do
that with your eyes too.

573
00:34:39,390 --> 00:34:42,190
But you close your eyes to
keep them nice and moist.

574
00:34:42,190 --> 00:34:44,040
So some people that doesn't
work terribly --

575
00:34:44,040 --> 00:34:49,620
I traveled across France in a
train with a guy who fell

576
00:34:49,620 --> 00:34:54,990
asleep but his eyes were open,
and it's like traveling across

577
00:34:54,990 --> 00:34:58,760
France with the undead.

578
00:34:58,760 --> 00:35:02,330
Because at some point he went
into REM sleep and his eyes

579
00:35:02,330 --> 00:35:06,340
were going all over the place,
but he ain't looking at

580
00:35:06,340 --> 00:35:09,570
nothing that's there.

581
00:35:09,570 --> 00:35:12,110
It was a little strange.

582
00:35:12,110 --> 00:35:17,360
So, so far, awake and dreaming
sleep look the same.

583
00:35:21,710 --> 00:35:24,020
If you think you're having
trouble telling whether your

584
00:35:24,020 --> 00:35:27,460
roommate's actually asleep,
here's how you can tell.

585
00:35:27,460 --> 00:35:32,220
You measure muscle tone,
electromyogram.

586
00:35:32,220 --> 00:35:36,010
When you are awake, your
muscles are on, right.

587
00:35:36,010 --> 00:35:36,990
You have good muscle tone.

588
00:35:36,990 --> 00:35:40,300
That's why your head doesn't
fall off of your shoulders and

589
00:35:40,300 --> 00:35:43,390
I can stand upright and
stuff like that.

590
00:35:43,390 --> 00:35:49,500
When you are in deep sleep,
actually your

591
00:35:49,500 --> 00:35:51,740
muscles remain on.

592
00:35:51,740 --> 00:35:52,980
The muscle tone remains high.

593
00:35:52,980 --> 00:35:56,020
It's when you go into
REM sleep that

594
00:35:56,020 --> 00:35:58,270
you lose muscle tone.

595
00:35:58,270 --> 00:36:04,520
You can see this in your
friendly neighborhood cat,

596
00:36:04,520 --> 00:36:06,910
because all this stuff
shows up widely

597
00:36:06,910 --> 00:36:08,320
in mammalian species.

598
00:36:08,320 --> 00:36:12,390
So, your cat who's sleeping
like this, that's a deeply

599
00:36:12,390 --> 00:36:16,270
sleeping cat whose muscle tone
is doing just fine, thank you.

600
00:36:16,270 --> 00:36:20,740
Your cat who's sleeping like
that is a cat who is in REM

601
00:36:20,740 --> 00:36:26,090
sleep and has lost
muscle tone.

602
00:36:26,090 --> 00:36:32,260
Now, why would you turn the
muscles off in REM sleep?

603
00:36:35,670 --> 00:36:36,920
AUDIENCE: [INAUDIBLE PHRASE].

604
00:36:44,100 --> 00:36:44,610
PROFESSOR: Yeah.

605
00:36:44,610 --> 00:36:48,280
If you're busy being Superman
and leaping tall buildings in

606
00:36:48,280 --> 00:36:51,900
a single bound in your dreams,
it's a really good idea if you

607
00:36:51,900 --> 00:36:56,520
don't actually try that out.

608
00:36:56,520 --> 00:37:00,350
Not only are you protecting
yourself, you're protecting

609
00:37:00,350 --> 00:37:03,430
anybody else you happen
to be sleeping with.

610
00:37:03,430 --> 00:37:08,770
A known sleep disorder in
older men is that this

611
00:37:08,770 --> 00:37:15,600
blockade of voluntary muscles
fades off, and the result --

612
00:37:15,600 --> 00:37:19,120
and this is a known disorder
because older women bring the

613
00:37:19,120 --> 00:37:23,710
older men to the doctor, because
their husband is

614
00:37:23,710 --> 00:37:28,750
thrashing around in the middle
of the night and whacking her.

615
00:37:28,750 --> 00:37:31,690
This is a real problem,
people get hurt.

616
00:37:31,690 --> 00:37:35,440
So, you want the muscles
to go off.

617
00:37:35,440 --> 00:37:36,670
There are a number of
corollaries here.

618
00:37:36,670 --> 00:37:41,780
It turns out that
sleep walking --

619
00:37:41,780 --> 00:37:43,370
Shakespeare has it wrong.

620
00:37:43,370 --> 00:37:47,480
Lady Macbeth is clearly dreaming
about having murdered

621
00:37:47,480 --> 00:37:50,380
Duncan and all that when
she's sleep walking.

622
00:37:50,380 --> 00:37:54,180
Typically, sleep walking is not
acting out your dreams.

623
00:37:54,180 --> 00:38:01,520
It is a version of non-REM
sleep, and it's much more

624
00:38:01,520 --> 00:38:04,890
typical in children
than in adults.

625
00:38:04,890 --> 00:38:07,510
How many of you know that used
to walk around at night when

626
00:38:07,510 --> 00:38:09,860
you were--?

627
00:38:09,860 --> 00:38:13,930
Little kids wandering around,
their eyes are open, but

628
00:38:13,930 --> 00:38:15,800
nobody's home here.

629
00:38:20,780 --> 00:38:22,720
I don't actually know
that much about it.

630
00:38:22,720 --> 00:38:27,660
My theory is that part of what's
doing this is it's your

631
00:38:27,660 --> 00:38:32,570
bladder telling you to get up
and the rest of your brain's

632
00:38:32,570 --> 00:38:34,340
saying we want to stay
asleep here.

633
00:38:34,340 --> 00:38:37,050
My theory is based on one
of the great moments of

634
00:38:37,050 --> 00:38:44,580
child-rearing in my household,
which was one of my children.

635
00:38:44,580 --> 00:38:47,840
We were awakened in the middle
of the night, my wife and I,

636
00:38:47,840 --> 00:38:55,390
by one of my son's yelling "No,
not here!" to the other

637
00:38:55,390 --> 00:38:59,310
son who was about to
use a trash can

638
00:38:59,310 --> 00:39:00,680
for the wrong purpose.

639
00:39:07,080 --> 00:39:09,200
Anyway, it all worked
out in the end.

640
00:39:11,890 --> 00:39:14,560
But this is a deep
sleep phenomenon.

641
00:39:14,560 --> 00:39:18,230
Talking in your sleep is
often, apparently,

642
00:39:18,230 --> 00:39:19,480
talking out of --

643
00:39:24,120 --> 00:39:30,830
you're not going to hurt
yourself too much if you don't

644
00:39:30,830 --> 00:39:35,470
blockade your jaw, right?

645
00:39:35,470 --> 00:39:39,190
It's the main body muscles
that are the real threat.

646
00:39:39,190 --> 00:39:43,490
So sometimes people will end
up talking in their sleep,

647
00:39:43,490 --> 00:39:49,860
often to the amusement of other
people in the room, or

648
00:39:49,860 --> 00:39:53,670
to the inconvenience of other
people, or of your own

649
00:39:53,670 --> 00:39:56,990
relationships, if what you're
talking about is somebody else

650
00:39:56,990 --> 00:40:01,270
other than the person who's
currently present with you.

651
00:40:01,270 --> 00:40:04,460
Anyway, it's not clear --

652
00:40:04,460 --> 00:40:06,630
when we get to meaning of dreams
we can talk about this.

653
00:40:06,630 --> 00:40:14,020
Anyway, so this is the sort of
within the circadian cycle,

654
00:40:14,020 --> 00:40:19,820
this is the sort of structure
you get in sleep.

655
00:40:22,900 --> 00:40:25,570
Oh, now there's much
more to this than

656
00:40:25,570 --> 00:40:26,310
what I'm telling you.

657
00:40:26,310 --> 00:40:31,070
Deep sleep can be subdivided
into multiple stages that

658
00:40:31,070 --> 00:40:33,680
differ in the activity of
different parts of your

659
00:40:33,680 --> 00:40:37,330
brain and so on.

660
00:40:41,600 --> 00:40:45,755
So now between that twenty-four
hour cycle and

661
00:40:45,755 --> 00:40:50,175
this ninety minute cycle, there
is yet another level of

662
00:40:50,175 --> 00:40:55,040
structure to a night's sleep
where there's more non-REM,

663
00:40:55,040 --> 00:40:58,220
slow wave, deep sleep
early in the night.

664
00:40:58,220 --> 00:41:02,650
If you have a consolidated bout
of eight hours of sleep,

665
00:41:02,650 --> 00:41:06,300
a normal night's sleep, what you
will see is more of this

666
00:41:06,300 --> 00:41:10,010
stuff early in the night
and more of this stuff

667
00:41:10,010 --> 00:41:11,420
later in the night.

668
00:41:11,420 --> 00:41:14,960
This is accompanied by
systematic changes in the

669
00:41:14,960 --> 00:41:19,070
neurochemistry of the sleeping
brain and so on.

670
00:41:19,070 --> 00:41:23,920
There's an intermediate level
of structure to sleep also.

671
00:41:23,920 --> 00:41:29,030
The impression one gets is of
a beautifully structured

672
00:41:29,030 --> 00:41:35,160
system that is designed
to do something.

673
00:41:35,160 --> 00:41:40,780
So, I mean apart from the
obvious, it's designed to keep

674
00:41:40,780 --> 00:41:44,160
you from feeling sleepy.

675
00:41:44,160 --> 00:41:52,630
One wants to know, well,
what is sleep for?

676
00:41:52,630 --> 00:41:56,150
You'd be surprised if a third of
your life is spent in this

677
00:41:56,150 --> 00:41:58,570
state for no good reason.

678
00:41:58,570 --> 00:42:04,510
Oh, look at that, it says Part
Two: Why do we sleep?

679
00:42:04,510 --> 00:42:08,450
It suggests that there are
several possible reasons here.

680
00:42:08,450 --> 00:42:11,260
Anybody care to offer
any possible

681
00:42:11,260 --> 00:42:13,670
series of why we sleep?

682
00:42:17,410 --> 00:42:18,760
Nobody's got a clue.

683
00:42:18,760 --> 00:42:20,090
Yes?

684
00:42:20,090 --> 00:42:21,340
AUDIENCE: [INAUDIBLE]

685
00:42:28,420 --> 00:42:31,340
PROFESSOR: So there's a sort
of a basic rest and

686
00:42:31,340 --> 00:42:33,840
regeneration notion.

687
00:42:33,840 --> 00:42:37,490
That you use your muscles all
day, it builds up all those

688
00:42:37,490 --> 00:42:41,280
metabolic byproducts in muscles
that you learned about

689
00:42:41,280 --> 00:42:42,790
once upon a time.

690
00:42:42,790 --> 00:42:47,340
Sleep/rest will give you a
chance to clear that out.

691
00:42:47,340 --> 00:42:49,860
So certainly, one possibility
is it's an

692
00:42:49,860 --> 00:42:50,920
enforced rest period.

693
00:42:50,920 --> 00:42:54,990
You could enforce rest some
other way, presumably.

694
00:42:54,990 --> 00:42:58,690
Well, it could be good for you
to rest, period -- just lie

695
00:42:58,690 --> 00:42:59,830
around and do nothing.

696
00:42:59,830 --> 00:43:02,030
But sleep kind of
enforces that.

697
00:43:02,030 --> 00:43:03,750
Yes, there was a hand over
there somewhere.

698
00:43:03,750 --> 00:43:07,130
AUDIENCE: [INAUDIBLE]

699
00:43:07,130 --> 00:43:10,560
PROFESSOR: So, there's a whole
class of theories, and these

700
00:43:10,560 --> 00:43:15,520
are actually the ones where
there's, I suppose, the most

701
00:43:15,520 --> 00:43:18,550
current interest that has to do
with learning and memory.

702
00:43:18,550 --> 00:43:25,090
That somehow what sleep is
about is tuning up your

703
00:43:25,090 --> 00:43:29,040
memories and you're
consolidating memories,

704
00:43:29,040 --> 00:43:32,110
improving learning or
something like that.

705
00:43:32,110 --> 00:43:33,670
Let's talk more about
that in a minute.

706
00:43:33,670 --> 00:43:36,100
But if you're sitting there
saying, I'm a real MIT

707
00:43:36,100 --> 00:43:37,850
student, I don't
need to sleep.

708
00:43:37,850 --> 00:43:41,120
You might worry about theories
that say sleep is vital to the

709
00:43:41,120 --> 00:43:44,460
consolidation of memory.

710
00:43:44,460 --> 00:43:44,840
Yeah?

711
00:43:44,840 --> 00:43:48,366
AUDIENCE: It's a lot easier to
rest during the day so we

712
00:43:48,366 --> 00:43:50,130
don't need to waste all the
energy [UNINTELLIGIBLE].

713
00:43:50,130 --> 00:43:52,460
PROFESSOR: So another
possibility is energy

714
00:43:52,460 --> 00:43:55,560
conservation.

715
00:43:55,560 --> 00:44:02,910
You could be awake all of the
time, but if you can't hunt

716
00:44:02,910 --> 00:44:11,270
when it's dark, you might as
well go and power down the

717
00:44:11,270 --> 00:44:15,720
disk drive or something
like that and

718
00:44:15,720 --> 00:44:16,210
not use as much energy.

719
00:44:16,210 --> 00:44:19,030
Your brain's pretty active while
you're asleep, as you

720
00:44:19,030 --> 00:44:21,110
may gather from this, but the
rest of you, of course, is

721
00:44:21,110 --> 00:44:23,560
getting some rest.

722
00:44:23,560 --> 00:44:25,440
Anything else?

723
00:44:25,440 --> 00:44:28,140
Any other good possibilities?

724
00:44:28,140 --> 00:44:36,590
Along with that energy
saving one --

725
00:44:36,590 --> 00:44:39,250
we can motivate this one related
to energy saving by

726
00:44:39,250 --> 00:44:43,100
asking where do you sleep
when it gets dark?

727
00:44:43,100 --> 00:44:46,330
AUDIENCE: [INAUDIBLE]

728
00:44:46,330 --> 00:44:47,080
PROFESSOR: In bed.

729
00:44:47,080 --> 00:44:47,910
That's seems like
a good place.

730
00:44:47,910 --> 00:44:49,040
Where did you put your bed?

731
00:44:49,040 --> 00:44:50,290
AUDIENCE: [INAUDIBLE]

732
00:44:55,480 --> 00:45:00,150
PROFESSOR: Anybody big on
sleeping on, like putting

733
00:45:00,150 --> 00:45:02,310
their bed out on the sidewalk?

734
00:45:02,310 --> 00:45:06,890
Those of you who are
hunter/gatherers, when you're

735
00:45:06,890 --> 00:45:10,770
tired you just lie down in
the middle of the field?

736
00:45:10,770 --> 00:45:11,650
No.

737
00:45:11,650 --> 00:45:14,750
Because it's not really
very safe.

738
00:45:14,750 --> 00:45:21,220
So another possibility is that
you want to sleep for purposes

739
00:45:21,220 --> 00:45:26,490
of protecting yourself
at times that are--

740
00:45:26,490 --> 00:45:29,880
as a corollary of this you
can't hunt all day thing.

741
00:45:29,880 --> 00:45:33,470
There are other things out
there that have adapted

742
00:45:33,470 --> 00:45:36,700
themselves to the niche
that you are not in.

743
00:45:36,700 --> 00:45:39,970
Like take hunt at night, so if
you're not going to hunt at

744
00:45:39,970 --> 00:45:43,620
night, not only do you want to
be calm and quiet, you want to

745
00:45:43,620 --> 00:45:47,390
be out of the way, because
otherwise oh, look, he's

746
00:45:47,390 --> 00:45:50,430
asleep, let's eat him.

747
00:45:50,430 --> 00:45:52,780
So there's a sort of a
safety aspect to it.

748
00:45:52,780 --> 00:45:54,920
The other part of the safety
aspect is that not only don't

749
00:45:54,920 --> 00:45:57,020
you want to hunt at night, if
you just go down wandering

750
00:45:57,020 --> 00:45:58,330
around aimlessly at night,
you're going to falli in a

751
00:45:58,330 --> 00:45:59,690
hole and hurt yourself.

752
00:45:59,690 --> 00:46:04,400
So, you've got to get in the
hole first and go to sleep.

753
00:46:04,400 --> 00:46:06,250
Do I have any other brilliant
theories here

754
00:46:06,250 --> 00:46:07,680
that I wanted to mention?

755
00:46:07,680 --> 00:46:08,350
That's pretty good.

756
00:46:08,350 --> 00:46:10,510
You guys managed to
do a quick survey

757
00:46:10,510 --> 00:46:14,170
of the leading theories.

758
00:46:14,170 --> 00:46:21,120
As I say, a lot of the cool,
current data centers around

759
00:46:21,120 --> 00:46:25,400
this idea of sleep having
a role in learning.

760
00:46:28,660 --> 00:46:30,920
Let me tell you a little
bit about that.

761
00:46:30,920 --> 00:46:35,890
The picture that's on the
handout is an illustration of

762
00:46:35,890 --> 00:46:40,010
what looks like a really
trivial task.

763
00:46:40,010 --> 00:46:45,480
The question is, is there a
little vertical region in that

764
00:46:45,480 --> 00:46:47,110
display somewhere?

765
00:46:47,110 --> 00:46:51,350
The answer is well, yeah.

766
00:46:51,350 --> 00:46:59,120
Now I can make that task
arbitrarily difficult by

767
00:46:59,120 --> 00:47:02,500
flashing the stimulus very
briefly and following it with

768
00:47:02,500 --> 00:47:04,510
a mask of some sort.

769
00:47:04,510 --> 00:47:08,580
So I can make it hard.

770
00:47:08,580 --> 00:47:11,330
I can make it as
hard as I like.

771
00:47:11,330 --> 00:47:22,670
If I do that, what I can do is
measure, let's call it a

772
00:47:22,670 --> 00:47:29,270
threshold time.

773
00:47:29,270 --> 00:47:34,590
So maybe in order for you to get
this task correct 70% of

774
00:47:34,590 --> 00:47:38,340
the time, I initially need to
have the stimulus on for 200

775
00:47:38,340 --> 00:47:39,590
milliseconds.

776
00:47:41,950 --> 00:47:50,350
If you practice it for a while,
you'll get better and

777
00:47:50,350 --> 00:47:53,030
that'll level off
at some point.

778
00:47:53,030 --> 00:47:55,920
What a number of
people have --

779
00:47:55,920 --> 00:47:58,370
well, is it Carney
and Sagi I think?

780
00:47:58,370 --> 00:48:02,000
Doug Sagi is the guy I know.

781
00:48:02,000 --> 00:48:04,565
What a number of people found,
starting I think with Carney

782
00:48:04,565 --> 00:48:12,150
and Sagi, is that if you let
people sleep, in particular if

783
00:48:12,150 --> 00:48:15,890
they are allowed to have
REM sleep, that

784
00:48:15,890 --> 00:48:17,900
performance gets --

785
00:48:17,900 --> 00:48:19,830
well, here's let's have him
sleep for eight hours here.

786
00:48:22,615 --> 00:48:28,780
That performance gets better, as
if something happened while

787
00:48:28,780 --> 00:48:29,660
they were asleep.

788
00:48:29,660 --> 00:48:31,300
If they don't sleep
during this period

789
00:48:31,300 --> 00:48:33,100
they don't get better.

790
00:48:33,100 --> 00:48:37,260
So it's a sleep dependent
improvement in behavior.

791
00:48:37,260 --> 00:48:41,450
This is a very specific little
bit of learning.

792
00:48:41,450 --> 00:48:43,460
This isn't just a
general overall

793
00:48:43,460 --> 00:48:45,060
improvement in behavior.

794
00:48:45,060 --> 00:48:49,400
If you trained people with that
little vertical task,

795
00:48:49,400 --> 00:48:52,170
that you're doing a task, is
that region vertical or

796
00:48:52,170 --> 00:48:53,060
horizontal, right.

797
00:48:53,060 --> 00:48:54,770
That the three thing is vertical
or the three thing is

798
00:48:54,770 --> 00:48:58,160
horizontal right It's always
I'm looking here and it's

799
00:48:58,160 --> 00:49:00,880
always down and to my left.

800
00:49:00,880 --> 00:49:04,550
I learn to be faster here.

801
00:49:04,550 --> 00:49:07,650
I don't learn to
be faster here.

802
00:49:07,650 --> 00:49:11,340
The improvement in learning is
specific to the little piece

803
00:49:11,340 --> 00:49:14,400
of retina that I have trained.

804
00:49:14,400 --> 00:49:20,590
So it's very specific sort of
learning that seems to be

805
00:49:20,590 --> 00:49:25,730
dependent on getting a
decent night's sleep.

806
00:49:25,730 --> 00:49:31,880
Now, interestingly, there is
evidence -- how many people

807
00:49:31,880 --> 00:49:33,130
here are nappers?

808
00:49:35,420 --> 00:49:38,730
How many people are nappers
just because it happens?

809
00:49:42,500 --> 00:49:43,810
We can do it this way.

810
00:49:43,810 --> 00:49:47,030
How many people here think that
if they take a nap in the

811
00:49:47,030 --> 00:49:50,540
middle of the day, they wake
up feeling better for the

812
00:49:50,540 --> 00:49:52,910
experience?

813
00:49:52,910 --> 00:49:56,900
How many people think if they
have a nap they wake up

814
00:49:56,900 --> 00:49:59,180
feeling cruddy for the
rest of the day?

815
00:50:02,480 --> 00:50:06,790
There are people who find naps
to be refreshing and useful,

816
00:50:06,790 --> 00:50:09,890
and there are people who find
it being disruptive.

817
00:50:09,890 --> 00:50:13,000
It was certainly a big
improvement in my professional

818
00:50:13,000 --> 00:50:15,170
life when I reached the
level where I had an

819
00:50:15,170 --> 00:50:18,530
office of my own.

820
00:50:18,530 --> 00:50:22,810
The biggest part of that was it
made napping a great deal

821
00:50:22,810 --> 00:50:24,580
more graceful.

822
00:50:24,580 --> 00:50:27,950
After lunch I could take the
latest issue of Vision

823
00:50:27,950 --> 00:50:33,990
Research and prop it up and
stare at the same two

824
00:50:33,990 --> 00:50:37,320
sentences for like fifteen
minutes and I feel much better

825
00:50:37,320 --> 00:50:38,570
thereafter.

826
00:50:41,790 --> 00:50:47,270
There is evidence that a
properly timed nap is just

827
00:50:47,270 --> 00:50:51,110
about as good as a night's
sleep for this sort of

828
00:50:51,110 --> 00:50:52,070
perceptual learning.

829
00:50:52,070 --> 00:50:54,180
This is work done
by Sara Mednick

830
00:50:54,180 --> 00:50:58,020
originally, up at Harvard.

831
00:50:58,020 --> 00:50:59,365
This is new stuff.

832
00:50:59,365 --> 00:51:04,600
We don't really quite understand
fully how far we

833
00:51:04,600 --> 00:51:05,610
can take this.

834
00:51:05,610 --> 00:51:10,470
It's the sort of thing that your
average MIT student is

835
00:51:10,470 --> 00:51:13,010
tempted to take and
run with, right.

836
00:51:13,010 --> 00:51:16,730
Oh man, I can get the whole
benefit of eight hours of

837
00:51:16,730 --> 00:51:19,330
sleep if I just go for --

838
00:51:19,330 --> 00:51:23,000
I think it's ninety minutes
between like 2:00 or 3:00 in

839
00:51:23,000 --> 00:51:24,530
the afternoon.

840
00:51:24,530 --> 00:51:25,840
That works.

841
00:51:25,840 --> 00:51:26,740
Great.

842
00:51:26,740 --> 00:51:28,750
Now I can stay up all night.

843
00:51:28,750 --> 00:51:30,270
Anyway, we don't
know that yet.

844
00:51:30,270 --> 00:51:34,580
But Mednick's study is an
interesting suggestion that

845
00:51:34,580 --> 00:51:36,650
sleep during--

846
00:51:36,650 --> 00:51:40,490
napping sleep can serve as
a same sort of perceptual

847
00:51:40,490 --> 00:51:42,940
learning kind of role.

848
00:51:42,940 --> 00:51:50,280
But look, one might actually
wonder whether anybody other

849
00:51:50,280 --> 00:51:55,030
than vision researchers cares
about whether or not you can

850
00:51:55,030 --> 00:51:59,510
find little briefly flashed
lines in one corner of your

851
00:51:59,510 --> 00:52:00,800
visual field.

852
00:52:00,800 --> 00:52:02,390
That's not what you
want to know about

853
00:52:02,390 --> 00:52:03,600
learning and memory.

854
00:52:03,600 --> 00:52:06,270
What you want to know is is
anything really useful

855
00:52:06,270 --> 00:52:08,220
happening while you're asleep.

856
00:52:08,220 --> 00:52:12,350
In particular, one of the things
that people want to

857
00:52:12,350 --> 00:52:18,610
know is, can you do serious
thinking in your sleep?

858
00:52:18,610 --> 00:52:25,890
One thing you can't do is
study in your sleep.

859
00:52:25,890 --> 00:52:28,710
There have been endless efforts
because people smelled

860
00:52:28,710 --> 00:52:33,880
money at the far end of this to
produce like tapes that you

861
00:52:33,880 --> 00:52:36,130
could stick under the pillow.

862
00:52:36,130 --> 00:52:41,080
Record Gleitman and why
waste precious waking

863
00:52:41,080 --> 00:52:43,570
hours reading Gleitman?

864
00:52:43,570 --> 00:52:45,860
I'll just have somebody
else read it to

865
00:52:45,860 --> 00:52:47,550
me while I'm asleep.

866
00:52:47,550 --> 00:52:51,510
Sorry, the overwhelming
evidence is

867
00:52:51,510 --> 00:52:53,530
that nothing happens.

868
00:52:53,530 --> 00:52:59,650
The mild effects that are
sporadically shown here come

869
00:52:59,650 --> 00:53:02,940
from periodic awakenings
during the night.

870
00:53:02,940 --> 00:53:06,240
That also goes for sleeping
through the lecture.

871
00:53:06,240 --> 00:53:08,840
If you're sound asleep during
the lecture it's lovely that

872
00:53:08,840 --> 00:53:12,210
you were here, but you'll have
to ask somebody else what

873
00:53:12,210 --> 00:53:15,350
actually happened.

874
00:53:15,350 --> 00:53:16,620
So that doesn't work.

875
00:53:16,620 --> 00:53:22,480
But can you have insights, or
can you do your problem sets

876
00:53:22,480 --> 00:53:26,320
during your sleep
in some sense?

877
00:53:26,320 --> 00:53:29,740
How many people have had the
experience of being sort of

878
00:53:29,740 --> 00:53:34,780
dead-ended on a problem, it's
time to just give it up, you

879
00:53:34,780 --> 00:53:38,100
go to sleep and you wake up and
somehow the answer kind of

880
00:53:38,100 --> 00:53:40,300
seems to be there?

881
00:53:40,300 --> 00:53:43,210
It's a not uncommon experienc
and there are lots of

882
00:53:43,210 --> 00:53:46,870
anecdotes in the literature
about this.

883
00:53:46,870 --> 00:53:52,300
One of the famous ones is the
guy who first described the

884
00:53:52,300 --> 00:53:56,340
ring structure of benzene,
claims that he had a dream of

885
00:53:56,340 --> 00:53:59,270
a snake biting his tail and he
woke up knowing that benzene

886
00:53:59,270 --> 00:54:01,150
was a ring or something.

887
00:54:01,150 --> 00:54:02,990
It doesn't always work,
by the way.

888
00:54:02,990 --> 00:54:11,070
My father spent his career as
a physicist and had the same

889
00:54:11,070 --> 00:54:11,675
experience.

890
00:54:11,675 --> 00:54:14,240
He's working on a problem,
not getting anywhere.

891
00:54:14,240 --> 00:54:17,830
Goes to sleep, wakes up in the
middle of the night, he knows

892
00:54:17,830 --> 00:54:22,150
the answer, and he knows you
don't remember stuff from the

893
00:54:22,150 --> 00:54:24,660
middle of the night, so he
writes it down fast and goes

894
00:54:24,660 --> 00:54:26,200
back to sleep.

895
00:54:26,200 --> 00:54:29,840
Gets up the next morning as
predicted, has no recollection

896
00:54:29,840 --> 00:54:32,140
of what the great answer was,
but he doesn't remember

897
00:54:32,140 --> 00:54:34,040
writing it down,
which is good.

898
00:54:34,040 --> 00:54:37,360
So he looks at it and he sees
that the answer is, "All the

899
00:54:37,360 --> 00:54:46,600
world is fused with the smell
of cinnamon," which I'm sure

900
00:54:46,600 --> 00:54:52,160
was an answer, but was it
necessarily the answer he was

901
00:54:52,160 --> 00:54:54,250
looking for.

902
00:54:54,250 --> 00:55:00,590
So this notion that you could
actually be doing something

903
00:55:00,590 --> 00:55:07,510
productive in that sense during
sleep was really in the

904
00:55:07,510 --> 00:55:12,000
realm of anecdote
until this year.

905
00:55:12,000 --> 00:55:15,840
I put the reference on the
paper by this group in

906
00:55:15,840 --> 00:55:18,070
Germany led by --

907
00:55:18,070 --> 00:55:19,780
I suppose since he's
in Germany, he must

908
00:55:19,780 --> 00:55:22,520
be Wagner et al.

909
00:55:22,520 --> 00:55:23,940
Beautiful experiment.

910
00:55:23,940 --> 00:55:29,460
You know these number games
where you get a string of

911
00:55:29,460 --> 00:55:31,210
numbers and you have
to predict the next

912
00:55:31,210 --> 00:55:33,920
number in the series?

913
00:55:33,920 --> 00:55:37,240
Well, I can't remember the
particular one here, which is

914
00:55:37,240 --> 00:55:40,240
just as well because at MIT all
that would happen is if I

915
00:55:40,240 --> 00:55:42,160
presented it, you'd be sitting
there for the rest of the

916
00:55:42,160 --> 00:55:44,790
lecture trying to work out
what's the rule here.

917
00:55:44,790 --> 00:55:47,650
Anyway, it's a clever --
go look at the paper.

918
00:55:47,650 --> 00:55:50,440
It's a beautiful paper.

919
00:55:50,440 --> 00:55:53,750
But they picked one of these
things where there were two

920
00:55:53,750 --> 00:55:55,240
ways to solve it.

921
00:55:55,240 --> 00:55:59,150
There is a sort of a laborious
multi-step thing.

922
00:55:59,150 --> 00:56:03,160
You add the last two numbers and
then divide by the third

923
00:56:03,160 --> 00:56:04,150
fac number.

924
00:56:04,150 --> 00:56:05,050
It's some weird thing.

925
00:56:05,050 --> 00:56:08,570
You can do it, but it
takes a long time.

926
00:56:08,570 --> 00:56:13,990
So, if you measure the
amount of time for --

927
00:56:13,990 --> 00:56:17,000
so this is going to
be time again.

928
00:56:17,000 --> 00:56:21,250
Measure the amount of time
to get the answer.

929
00:56:21,250 --> 00:56:25,520
People are initially very long
and then they get better and

930
00:56:25,520 --> 00:56:27,540
to get to some sort of stable.

931
00:56:27,540 --> 00:56:30,340
But there's a trick.

932
00:56:30,340 --> 00:56:34,630
If you have this flash of
insight, you realize I don't

933
00:56:34,630 --> 00:56:37,190
remember what, but there's some
trivial way of knowing

934
00:56:37,190 --> 00:56:42,080
what the number is, and if you
get it, it's trivial to see in

935
00:56:42,080 --> 00:56:45,720
the data because your time
drops like a rock

936
00:56:45,720 --> 00:56:48,710
and it stays there.

937
00:56:48,710 --> 00:56:51,740
So now what you do is
you take people, you

938
00:56:51,740 --> 00:56:53,870
train them on this.

939
00:56:53,870 --> 00:57:01,000
They're at this the high
asymptote here, and

940
00:57:01,000 --> 00:57:02,690
you send them away.

941
00:57:02,690 --> 00:57:07,850
You either send them away for
eight hours of daytime stuff

942
00:57:07,850 --> 00:57:10,670
-- come back tonight we'll
test you again.

943
00:57:10,670 --> 00:57:12,570
You send them away --

944
00:57:12,570 --> 00:57:14,170
I don't remember, do they
actually keep them in the lab?

945
00:57:14,170 --> 00:57:16,480
You can keep them in the lab
and keep them awake.

946
00:57:16,480 --> 00:57:18,610
Anyway, you send them away at
night because you want to make

947
00:57:18,610 --> 00:57:20,690
sure that it's not a day/night
thing, but

948
00:57:20,690 --> 00:57:21,860
don't let them sleep.

949
00:57:21,860 --> 00:57:26,780
Or you have people who go to
sleep and have eight hours

950
00:57:26,780 --> 00:57:28,500
worth of sleep.

951
00:57:28,500 --> 00:57:33,200
The finding is that
the next day --

952
00:57:33,200 --> 00:57:36,900
eight hours later rather --

953
00:57:36,900 --> 00:57:42,940
some people are here, some
people are here or rapidly get

954
00:57:42,940 --> 00:57:48,280
here, and 50% more of
the people who had a

955
00:57:48,280 --> 00:57:51,000
night's sleep got here.

956
00:57:51,000 --> 00:57:53,620
It's not that everybody went to
sleep and had this kaboom

957
00:57:53,620 --> 00:57:54,900
of insight.

958
00:57:54,900 --> 00:58:02,570
But seemingly something about
that night sleep produced this

959
00:58:02,570 --> 00:58:10,165
rapid burst of insight in many
more people in the sleep group

960
00:58:10,165 --> 00:58:13,240
than in the two other groups.

961
00:58:13,240 --> 00:58:17,250
It's I think the first really
good evidence, experimental

962
00:58:17,250 --> 00:58:28,590
evidence, for an ability to get
something more like higher

963
00:58:28,590 --> 00:58:32,680
level cognitive thought
happening while you're asleep,

964
00:58:32,680 --> 00:58:35,990
Not just these relatively low
level perceptual learning

965
00:58:35,990 --> 00:58:37,200
kinds of things.

966
00:58:37,200 --> 00:58:44,240
So, the general evidence
suggests that sleep has an

967
00:58:44,240 --> 00:58:50,980
important role to play in
managing your cognitive light

968
00:58:50,980 --> 00:58:52,420
in some fashion.

969
00:58:52,420 --> 00:58:56,080
It probably serves a role
in consolidating memory.

970
00:58:56,080 --> 00:59:02,950
It probably serves a role
in problem solving.

971
00:59:02,950 --> 00:59:06,610
It certainly is the sort of
thing that one might think

972
00:59:06,610 --> 00:59:10,740
about as one is saying I'm going
to stay up all night

973
00:59:10,740 --> 00:59:15,420
reading Gleitman because
tomorrow's the final exam.

974
00:59:15,420 --> 00:59:17,960
Well, if you haven't read
Gleitman before the final exam

975
00:59:17,960 --> 00:59:21,190
it's probably true that reading
Gleitman all night is

976
00:59:21,190 --> 00:59:24,100
better than hoping that eight
hours of sleep will produce a

977
00:59:24,100 --> 00:59:27,170
flash of insight about the
imagined contents of Gleitman.

978
00:59:31,100 --> 00:59:35,320
All right, let us discuss --

979
00:59:35,320 --> 00:59:37,170
I'm supposed to tell you what's
going to happen when

980
00:59:37,170 --> 00:59:41,060
you're sleep deprived I see, but
let's do that in a minute

981
00:59:41,060 --> 00:59:46,190
after you wake up the person
next to you who's dozed off.

982
00:59:46,190 --> 00:59:47,430
Because they want to
hear this piece.

983
00:59:47,430 --> 01:03:05,620
[INTERMISSION IN LECTURE]

984
01:03:05,620 --> 01:03:05,970
All right.

985
01:03:05,970 --> 01:03:10,730
So what happens to you, you were
clearly built to sleep.

986
01:03:10,730 --> 01:03:16,015
What happens if you abuse the
privilege and you're running a

987
01:03:16,015 --> 01:03:17,450
sleep debt?

988
01:03:17,450 --> 01:03:22,640
And the answer is most people
here, in fact, most people in

989
01:03:22,640 --> 01:03:25,990
America are running some
sort of a sleep debt.

990
01:03:25,990 --> 01:03:30,610
What is the cost?

991
01:03:30,610 --> 01:03:35,870
Well, you can measure cost in
a variety of different ways.

992
01:03:35,870 --> 01:03:45,260
You can certainly measure cost
in terms of things like

993
01:03:45,260 --> 01:03:48,090
industrial accidents, car
crashes and stuff like that.

994
01:03:48,090 --> 01:03:55,840
The classic sleep deprivation
car crash is a crash on a

995
01:03:55,840 --> 01:04:00,860
clear straight road on
a moonlit night --

996
01:04:00,860 --> 01:04:03,290
you're a nice long distance
trucker who's abusing the

997
01:04:03,290 --> 01:04:04,670
rules about how long you're
supposed to be

998
01:04:04,670 --> 01:04:06,810
able to drive at once.

999
01:04:06,810 --> 01:04:09,720
You're out, there's no car in
the vicinity, the road is

1000
01:04:09,720 --> 01:04:13,550
straight, it's not bright
light, but you can see

1001
01:04:13,550 --> 01:04:14,040
everything.

1002
01:04:14,040 --> 01:04:17,500
The road turns a few degrees and
you go straight out into

1003
01:04:17,500 --> 01:04:19,470
the cactus or something
like that.

1004
01:04:19,470 --> 01:04:23,990
Because when you get really
sleepy, if you take a look at

1005
01:04:23,990 --> 01:04:26,260
people's brain waves, you can
watch them flipping into these

1006
01:04:26,260 --> 01:04:31,080
little micro sleeps that don't
necessarily last very long,

1007
01:04:31,080 --> 01:04:34,217
but at sixty miles an hour,
eighty miles an hour, ninety

1008
01:04:34,217 --> 01:04:36,600
miles an hour, they don't need
to last very long for you to

1009
01:04:36,600 --> 01:04:41,060
end up in sage brush.

1010
01:04:41,060 --> 01:04:44,480
There are plenty of ways to
measure it in the lab too.

1011
01:04:44,480 --> 01:04:51,630
If you sit somebody in the lab
and tell them all I want you

1012
01:04:51,630 --> 01:04:58,290
to do is push a button when I
turn on this little light.

1013
01:04:58,290 --> 01:05:00,700
The only thing you need to do.

1014
01:05:00,700 --> 01:05:05,380
What you discover is that
people are about 200

1015
01:05:05,380 --> 01:05:11,020
milliseconds slower at adverse
circadian phase, at the bottom

1016
01:05:11,020 --> 01:05:17,490
of that circadian trough than
they are at the top of it.

1017
01:05:17,490 --> 01:05:19,700
And on top that just
general slowing.

1018
01:05:19,700 --> 01:05:21,620
There are also a whole bunch
of times when they'll just

1019
01:05:21,620 --> 01:05:23,610
miss the light altogether.

1020
01:05:23,610 --> 01:05:31,460
The light will come on and the
subject will be just ah and

1021
01:05:31,460 --> 01:05:32,540
not do anything about it.

1022
01:05:32,540 --> 01:05:37,620
Now, 200 milliseconds, what's
the big deal there?

1023
01:05:37,620 --> 01:05:39,160
It's only a fifth of a second.

1024
01:05:39,160 --> 01:05:42,860
Well, again, at ninety miles an
hour it makes a difference

1025
01:05:42,860 --> 01:05:47,240
and if you're flying your
supersonic jet around the

1026
01:05:47,240 --> 01:05:49,410
skies of Iraq or something
it makes even more of a

1027
01:05:49,410 --> 01:05:50,280
difference.

1028
01:05:50,280 --> 01:05:54,350
So there's a generalized
slowing.

1029
01:05:54,350 --> 01:06:02,590
There is a tendency to trade-off
speed and accuracy

1030
01:06:02,590 --> 01:06:06,020
more than usual in
favor of speed.

1031
01:06:06,020 --> 01:06:10,480
So people tend, when
they're sleepy --

1032
01:06:10,480 --> 01:06:12,780
we've actually done
this in our lab.

1033
01:06:12,780 --> 01:06:15,020
So if you're doing one of these
visual search kinds of

1034
01:06:15,020 --> 01:06:17,160
things where you're looking for
something exciting like

1035
01:06:17,160 --> 01:06:22,600
where's the red vertical line,
people, if you go too fast you

1036
01:06:22,600 --> 01:06:23,700
make mistakes.

1037
01:06:23,700 --> 01:06:27,000
People when they're sleepy tend
to be willing to tolerate

1038
01:06:27,000 --> 01:06:28,930
higher error rates.

1039
01:06:28,930 --> 01:06:32,100
Again, that's the sort of thing
that is brought out into

1040
01:06:32,100 --> 01:06:37,130
the real world if your error
rate goes up by two or three

1041
01:06:37,130 --> 01:06:39,960
times, that could be
a real problem in

1042
01:06:39,960 --> 01:06:42,300
doing real world tasks.

1043
01:06:42,300 --> 01:06:46,110
It is harder to prove but
pretty clear, perhaps

1044
01:06:46,110 --> 01:06:51,500
introspectively, that being
sleepy makes you stupid.

1045
01:06:51,500 --> 01:06:54,960
You just don't think as well.

1046
01:06:54,960 --> 01:06:57,960
For a long time it was kind of
hard to show any effects of

1047
01:06:57,960 --> 01:07:00,580
sleep deprivation because people
tended to do things

1048
01:07:00,580 --> 01:07:05,110
like ask you to add up columns
of numbers, and as long as I

1049
01:07:05,110 --> 01:07:07,840
smack you around enough to
keep you awake during the

1050
01:07:07,840 --> 01:07:10,600
task, you can do that.

1051
01:07:10,600 --> 01:07:14,280
But if I ask you to do, I don't
know, your problem set

1052
01:07:14,280 --> 01:07:17,540
when you're really sleepy, it
turns out that the throughput

1053
01:07:17,540 --> 01:07:23,790
on more complicated cognitive
tasks goes downhill.

1054
01:07:23,790 --> 01:07:25,160
You're just not as good at it.

1055
01:07:25,160 --> 01:07:28,070
Will it kill you?

1056
01:07:28,070 --> 01:07:29,530
How bad can it be?

1057
01:07:29,530 --> 01:07:32,810
The answer is probably yes.

1058
01:07:32,810 --> 01:07:38,460
Not obviously at the level
that people inflict on

1059
01:07:38,460 --> 01:07:42,090
themselves, but prolonged sleep
deprivation will kill

1060
01:07:42,090 --> 01:07:45,760
you if you are a
rat, at least.

1061
01:07:45,760 --> 01:07:49,430
What kills you is not that you
just get so sleepy that you

1062
01:07:49,430 --> 01:07:55,870
fall over dead, but that staying
awake, or more to the

1063
01:07:55,870 --> 01:08:00,320
point being kept awake, which
is what's required if you're

1064
01:08:00,320 --> 01:08:02,720
going to go any extended period
of sleep deprivation,

1065
01:08:02,720 --> 01:08:08,400
is highly stressful, and
stress will kill you.

1066
01:08:08,400 --> 01:08:12,090
The rats who die in sleep
deprivation studies die of

1067
01:08:12,090 --> 01:08:16,050
things like bleeding ulcers
and stuff like that.

1068
01:08:16,050 --> 01:08:21,850
Symptoms that look for all the
world like the effects of

1069
01:08:21,850 --> 01:08:24,880
severe stress.

1070
01:08:24,880 --> 01:08:29,740
You can also ask whether or not
deprivation of particular

1071
01:08:29,740 --> 01:08:34,980
kinds of sleep is particularly
damaging.

1072
01:08:34,980 --> 01:08:39,570
So, for example, it's relatively
easy to deprive

1073
01:08:39,570 --> 01:08:41,610
somebody of REM sleep.

1074
01:08:41,610 --> 01:08:47,040
You can just monitor their eye
movements or their brain waves

1075
01:08:47,040 --> 01:08:51,200
and wake them up every time
they go into REM sleep.

1076
01:08:51,200 --> 01:08:56,290
They will sleep for most of
the night that way, but

1077
01:08:56,290 --> 01:08:58,200
they'll have little or no REM.

1078
01:08:58,200 --> 01:09:01,160
You do get effects of that
on these perceptual

1079
01:09:01,160 --> 01:09:02,020
learning tasks --

1080
01:09:02,020 --> 01:09:05,600
REM seems to be important
in that.

1081
01:09:05,600 --> 01:09:08,960
But you can be REM deprived for
an extended period of time

1082
01:09:08,960 --> 01:09:14,280
without collapsing in a heap.

1083
01:09:14,280 --> 01:09:15,700
There are two reasons
we know that.

1084
01:09:15,700 --> 01:09:17,320
One of them is that
people have done

1085
01:09:17,320 --> 01:09:18,000
experimental studies of this.

1086
01:09:18,000 --> 01:09:21,010
The other is that one class of
antidepressants known as

1087
01:09:21,010 --> 01:09:29,330
Monoamine Oxidase Inhibitors,
MAOIs, systematically suppress

1088
01:09:29,330 --> 01:09:34,770
REM sleep, and these patients
report that they don't dream.

1089
01:09:34,770 --> 01:09:37,545
But they don't have obvious
evil side effects.

1090
01:09:37,545 --> 01:09:39,470
We don't quite understand
how that

1091
01:09:39,470 --> 01:09:41,200
relates to these theories.

1092
01:09:41,200 --> 01:09:43,890
People on these things don't
say oh my goodness, I can't

1093
01:09:43,890 --> 01:09:44,476
learn anymore.

1094
01:09:44,476 --> 01:09:47,036
So there's something we don't
understand about the

1095
01:09:47,036 --> 01:09:50,660
relationship between REM and
learning there, because

1096
01:09:50,660 --> 01:09:52,820
otherwise these antidepressants
would have a

1097
01:09:52,820 --> 01:09:54,930
powerful side effect, cognitive
side effect

1098
01:09:54,930 --> 01:09:56,260
that we don't see.

1099
01:09:56,260 --> 01:10:00,920
The other way to do this in
animal studies is to keep an

1100
01:10:00,920 --> 01:10:04,240
animal REM deprived for a month
at a time and see if the

1101
01:10:04,240 --> 01:10:10,270
animal show these sort of
stress symptoms, and the

1102
01:10:10,270 --> 01:10:13,010
answer seems to be, well,
no, not really.

1103
01:10:13,010 --> 01:10:17,490
If you get sleep, even without
REM sleep, the stress part can

1104
01:10:17,490 --> 01:10:18,480
not be there.

1105
01:10:18,480 --> 01:10:23,840
Oh, my favorite technique for
REM depriving a cat in this

1106
01:10:23,840 --> 01:10:26,280
case, this is a low REM -- if
you want to REM deprive your

1107
01:10:26,280 --> 01:10:29,650
cat, here's how you do it.

1108
01:10:29,650 --> 01:10:33,980
You put the cat -- take a flower
pot, turn the flower

1109
01:10:33,980 --> 01:10:37,000
pot upside-down, put the cat
on the flower pot in the

1110
01:10:37,000 --> 01:10:40,870
middle of a little
artificial lake.

1111
01:10:40,870 --> 01:10:45,540
Eventually the cat goes
to sleep, right.

1112
01:10:45,540 --> 01:10:49,760
Then the cat falls
into REM sleep.

1113
01:10:49,760 --> 01:10:52,920
Falls off into the water.

1114
01:10:52,920 --> 01:10:54,850
Cat doesn't like to fall
into the water.

1115
01:10:54,850 --> 01:10:57,660
Cat wakes up.

1116
01:10:57,660 --> 01:11:05,250
And the cats learns the
not go into REM sleep.

1117
01:11:05,250 --> 01:11:09,200
In some sense, trains itself
not to fall into REM sleep,

1118
01:11:09,200 --> 01:11:12,290
with the result that you can
REM deprive the cat for an

1119
01:11:12,290 --> 01:11:14,020
extended period of time.

1120
01:11:14,020 --> 01:11:15,730
This is a very weird study.

1121
01:11:15,730 --> 01:11:18,130
I don't where they got
their measures.

1122
01:11:18,130 --> 01:11:20,810
The only thing I can remember
that the only thing they found

1123
01:11:20,810 --> 01:11:25,290
that was unusual about this cat
is that a normal cat, you

1124
01:11:25,290 --> 01:11:29,720
got the cat food, if you put a
July the 4th kind of sparkler

1125
01:11:29,720 --> 01:11:34,420
in the cat food, a normal cat
will not eat the the cat food,

1126
01:11:34,420 --> 01:11:36,240
but a REM deprived cat will.

1127
01:11:36,240 --> 01:11:39,300
Why?

1128
01:11:39,300 --> 01:11:39,940
I don't know.

1129
01:11:39,940 --> 01:11:41,910
I don't know nothing
about this.

1130
01:11:41,910 --> 01:11:46,650
I only know what I read
in the literature.

1131
01:11:46,650 --> 01:11:49,600
Which reminds me, however --
actually, this should have

1132
01:11:49,600 --> 01:11:51,820
reminded me.

1133
01:11:51,820 --> 01:11:54,065
That the most practical piece of
advice, apart from the fact

1134
01:11:54,065 --> 01:11:57,650
you should get eight hours
of sleep at night.

1135
01:11:57,650 --> 01:12:00,630
Since you won't get eight hours
of sleep a night, I

1136
01:12:00,630 --> 01:12:03,460
notice, I've been lecturing to
this course for twenty plus

1137
01:12:03,460 --> 01:12:10,020
years, and in spite of my
exortations that your physical

1138
01:12:10,020 --> 01:12:13,210
and cognitive well-being really
relies on you going to

1139
01:12:13,210 --> 01:12:15,010
sleep at night, none of you are
going to pay the slightest

1140
01:12:15,010 --> 01:12:16,260
bit of attention to that.

1141
01:12:16,260 --> 01:12:19,190
So the more practical piece of
advice I can give you is how

1142
01:12:19,190 --> 01:12:20,440
to sleep in class.

1143
01:12:22,730 --> 01:12:23,970
The trick is --

1144
01:12:23,970 --> 01:12:28,450
I mean obviously what you want
to do is you want to sleep in

1145
01:12:28,450 --> 01:12:33,790
a way that kind of
masks that fact.

1146
01:12:33,790 --> 01:12:36,430
The difficulty is this
REM sleep business.

1147
01:12:39,040 --> 01:12:47,600
The problem is the muscle tone
thing and it's the head bob

1148
01:12:47,600 --> 01:12:48,850
portion of the--

1149
01:12:53,310 --> 01:13:01,370
So I can look out there and
watch the whiplash and that's

1150
01:13:01,370 --> 01:13:03,640
not going to work.

1151
01:13:03,640 --> 01:13:09,730
So, what people figure out on
their own is that what you

1152
01:13:09,730 --> 01:13:14,190
want to do is you want to give
the illusion that what I or

1153
01:13:14,190 --> 01:13:19,628
somebody else is saying is so
deep that you had to close

1154
01:13:19,628 --> 01:13:21,820
your eyes to think about it.

1155
01:13:21,820 --> 01:13:25,800
Now, there are a couple of
important principles here.

1156
01:13:25,800 --> 01:13:32,050
One of them is that it's less
convincing that you're

1157
01:13:32,050 --> 01:13:37,290
thinking deeply about this
if your mouth falls open.

1158
01:13:37,290 --> 01:13:41,170
If you're drooling
it's really bad.

1159
01:13:41,170 --> 01:13:45,830
This is good.

1160
01:13:45,830 --> 01:13:47,960
Support for the chin is good.

1161
01:13:47,960 --> 01:13:53,010
The other thing that you learned
in like 801 was that

1162
01:13:53,010 --> 01:13:54,920
three-legged stools
stand better than

1163
01:13:54,920 --> 01:13:56,920
two-legged ones, right?

1164
01:13:56,920 --> 01:13:58,170
So, I favor these.

1165
01:14:01,600 --> 01:14:06,180
I'm really thinking very hard
about what you're saying.

1166
01:14:06,180 --> 01:14:07,560
That can actually be
quite -- in fact,

1167
01:14:07,560 --> 01:14:08,950
you're not fooling anybody.

1168
01:14:08,950 --> 01:14:11,640
You know perfectly well
you're sound asleep.

1169
01:14:11,640 --> 01:14:12,020
What?

1170
01:14:12,020 --> 01:14:14,250
AUDIENCE: [INAUDIBLE]

1171
01:14:14,250 --> 01:14:16,000
PROFESSOR: Oh, keeping the
airway open is good.

1172
01:14:16,000 --> 01:14:22,830
That was the winner of the most
embarrassing moment in

1173
01:14:22,830 --> 01:14:27,470
Intro Psych Student
Experience.

1174
01:14:27,470 --> 01:14:29,900
This was actually the
first year I was

1175
01:14:29,900 --> 01:14:30,240
teaching the course.

1176
01:14:30,240 --> 01:14:35,923
I was co-teaching it with
another guy in course nine at

1177
01:14:35,923 --> 01:14:39,050
the time and he was lecturing.

1178
01:14:39,050 --> 01:14:41,400
I've long ago stopped figuring
that this was an editorial

1179
01:14:41,400 --> 01:14:42,640
comment when people
fall asleep.

1180
01:14:42,640 --> 01:14:46,170
But anyway, somebody sitting
right about over there fell

1181
01:14:46,170 --> 01:14:48,200
sound asleep.

1182
01:14:48,200 --> 01:14:52,370
But nobody was sitting
next to them.

1183
01:14:52,370 --> 01:14:56,400
They fell sound asleep and
they started to snore.

1184
01:14:56,400 --> 01:15:02,880
Eventually this got like loud
enough that my colleague had

1185
01:15:02,880 --> 01:15:04,560
to say somebody's going.

1186
01:15:04,560 --> 01:15:07,620
If you want the definition of
embarrassed -- the definition

1187
01:15:07,620 --> 01:15:09,540
of embarrassed is you're
sitting in lecture,

1188
01:15:09,540 --> 01:15:18,680
everybody's looking at you
and you have no idea why.

1189
01:15:18,680 --> 01:15:21,105
So, sitting next to somebody's
another good strategy if

1190
01:15:21,105 --> 01:15:22,980
you're actually trying to
stay more or less alert.

1191
01:15:22,980 --> 01:15:28,860
My old doctoral advisor and I
had this as a pact when I was

1192
01:15:28,860 --> 01:15:32,270
in graduate school during the
Friday afternoon, terrible

1193
01:15:32,270 --> 01:15:34,440
time, departmental colloquia.

1194
01:15:34,440 --> 01:15:37,730
We would sit next to each other
and if it was actually

1195
01:15:37,730 --> 01:15:41,650
talk that we cared about, we had
an agreement, if I go out,

1196
01:15:41,650 --> 01:15:43,550
poke me, because I kind of want
to know what this guy is

1197
01:15:43,550 --> 01:15:44,800
talking about.

1198
01:15:44,800 --> 01:15:47,100
He was department chair.

1199
01:15:47,100 --> 01:15:48,960
Turns out to be very important,
because one of the

1200
01:15:48,960 --> 01:15:51,920
rules of you're department chair
is you have to be able

1201
01:15:51,920 --> 01:15:55,650
to ask an intelligent question
at the end of the talk.

1202
01:15:55,650 --> 01:15:57,900
Really good department chairs
can do that after sleeping

1203
01:15:57,900 --> 01:15:59,670
through the talk.

1204
01:15:59,670 --> 01:16:03,430
My advisor, who was otherwise an
exemplary department chair,

1205
01:16:03,430 --> 01:16:08,980
was caught up short on this at
one talk where he asked a very

1206
01:16:08,980 --> 01:16:11,910
good question, but one that he
wouldn't have asked had he

1207
01:16:11,910 --> 01:16:14,950
been awake for those twenty
minutes of the talk.

1208
01:16:14,950 --> 01:16:17,620
Because the guy had discussed
this matter extensively.

1209
01:16:17,620 --> 01:16:21,260
So if we would poke each
other to stay awake.

1210
01:16:21,260 --> 01:16:25,770
The guy joined our lab and he
sat two seats away from me.

1211
01:16:25,770 --> 01:16:27,430
He went out cold.

1212
01:16:27,430 --> 01:16:29,350
That's OK.

1213
01:16:29,350 --> 01:16:30,450
But he started shouting.

1214
01:16:30,450 --> 01:16:35,620
In Japanese.

1215
01:16:35,620 --> 01:16:37,430
Actually, it was probably a
bonus that it was in Japanese

1216
01:16:37,430 --> 01:16:39,560
because whatever he was shouting
was incomprehensible

1217
01:16:39,560 --> 01:16:42,180
to anybody else.

1218
01:16:42,180 --> 01:16:46,280
I made this sort of dramatic
lunge to get to him before he

1219
01:16:46,280 --> 01:16:48,830
could manage to get
out too much.

1220
01:16:53,100 --> 01:16:56,140
So now if you're worried about
that, you kind of want to be

1221
01:16:56,140 --> 01:16:59,860
sitting with your friends here
so that when you start talking

1222
01:16:59,860 --> 01:17:03,300
in your sleep, somebody can get
to you before it becomes

1223
01:17:03,300 --> 01:17:05,840
really desperately obvious.

1224
01:17:05,840 --> 01:17:06,820
All right.

1225
01:17:06,820 --> 01:17:13,020
I suppose the bottom line is
that sleep deprivation will

1226
01:17:13,020 --> 01:17:18,870
not kill you, but it won't do
anything good for you, except

1227
01:17:18,870 --> 01:17:21,060
perhaps getting you through
the your work.

1228
01:17:21,060 --> 01:17:28,080
Now, let's see do I want to --
you know this looks like a

1229
01:17:28,080 --> 01:17:33,950
pretty good place to entertain
questions and we'll go on to

1230
01:17:33,950 --> 01:17:36,360
dreaming after Thanksgiving.

1231
01:17:36,360 --> 01:17:39,360
Any sleep questions
while we're here?

1232
01:17:42,900 --> 01:17:44,790
We got a question, then
you can run for it.

1233
01:17:44,790 --> 01:17:46,040
AUDIENCE: [INAUDIBLE]

1234
01:17:52,580 --> 01:17:56,480
PROFESSOR: Well, the piece of
that is right -- so the

1235
01:17:56,480 --> 01:17:58,840
question is do you
want to sleeps in

1236
01:17:58,840 --> 01:18:00,310
cycles of ninety minutes?

1237
01:18:00,310 --> 01:18:02,890
Ideally, you want to wake
up on your own.

1238
01:18:02,890 --> 01:18:06,640
Typically out of the end of
a REM stage is what would

1239
01:18:06,640 --> 01:18:09,150
normally happen.

1240
01:18:09,150 --> 01:18:11,460
Yes, you will tend to feel more
refreshed there than if

1241
01:18:11,460 --> 01:18:13,680
you wake up out of this.

1242
01:18:13,680 --> 01:18:18,580
But most of us wake up
when the alarm clock

1243
01:18:18,580 --> 01:18:20,110
goes off and sorry.

1244
01:18:20,110 --> 01:18:23,450
But if you can manage to adjust
that to wake you up --

1245
01:18:23,450 --> 01:18:25,390
even if you have to move it a
little earlier, you may feel

1246
01:18:25,390 --> 01:18:26,660
better if you're waking
yourself up

1247
01:18:26,660 --> 01:18:29,380
out of a REM state.

1248
01:18:29,380 --> 01:18:30,630
Yup?

1249
01:18:32,550 --> 01:18:35,760
AUDIENCE: [INAUDIBLE]

1250
01:18:35,760 --> 01:18:39,130
PROFESSOR: Oh, that's the
neck floppy thing.

1251
01:18:39,130 --> 01:18:43,150
When your muscles are going,
when you're losing muscle tone

1252
01:18:43,150 --> 01:18:48,270
and drifting off into a REM
state, bits of you are kind of

1253
01:18:48,270 --> 01:18:52,030
going where gravity wants to
go and that can feel like a

1254
01:18:52,030 --> 01:18:55,000
falling sensation, which
inconveniently can sometimes

1255
01:18:55,000 --> 01:18:57,744
lurch you back awake, or
conveniently if you happen to

1256
01:18:57,744 --> 01:19:00,520
be going out during class.

1257
01:19:00,520 --> 01:19:03,960
But I think that's typically
an effect of the

1258
01:19:03,960 --> 01:19:05,400
losing muscle tone part.

1259
01:19:08,840 --> 01:19:09,910
Last chance, here we go.

1260
01:19:09,910 --> 01:19:11,160
AUDIENCE: [INAUDIBLE]

1261
01:19:16,010 --> 01:19:17,750
PROFESSOR: Oh, if you really
live in really, really

1262
01:19:17,750 --> 01:19:21,070
northern -- sleep disorders
go up as latitude

1263
01:19:21,070 --> 01:19:23,330
goes up or way down.

1264
01:19:23,330 --> 01:19:27,370
But as long as you're living
someplace where the sun comes

1265
01:19:27,370 --> 01:19:29,690
up every day, that's
not an issue.

1266
01:19:29,690 --> 01:19:32,600
But yes, absolutely, if you go
and live someplace where it's

1267
01:19:32,600 --> 01:19:37,160
dark for six months of the year,
people have disruptions

1268
01:19:37,160 --> 01:19:41,570
of their circadian clock and
they start free-running.

1269
01:19:41,570 --> 01:19:42,780
All right.

1270
01:19:42,780 --> 01:19:43,940
Drive carefully.

1271
01:19:43,940 --> 01:19:45,630
Have a good vacation.