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LIZ SPELKE: I want
to talk about--

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00:00:23,465 --> 00:00:27,506
you asked about development
of knowledge within infancy--

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00:00:27,506 --> 00:00:28,880
and I want to talk
about one case

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where we've seen an interesting
developmental change.

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00:00:31,088 --> 00:00:33,687
One that I don't think we
really fully understand.

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I'm sure we don't
fully understand it.

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I'm not sure we
understand it at all.

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But it seems to be there.

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00:00:39,620 --> 00:00:43,520
And it has to do with
effects of both, maybe,

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00:00:43,520 --> 00:00:45,140
inertial properties
of object motion

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00:00:45,140 --> 00:00:48,200
and also effects of
gravity on object motion.

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Let me just tell you
the result first.

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00:00:50,090 --> 00:00:52,850
These are studies that
were done by In-Kyeong Kim

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00:00:52,850 --> 00:00:54,770
a long time ago.

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00:00:54,770 --> 00:00:57,020
But recently enough,
that video was

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00:00:57,020 --> 00:01:00,650
part of our toolkit, which
wasn't always the case,

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00:01:00,650 --> 00:01:04,670
and involved showing
babies videotapes of events

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00:01:04,670 --> 00:01:06,980
in which an object
held by a hand

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00:01:06,980 --> 00:01:12,130
was placed on an inclined plane,
released, and started to move.

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00:01:12,130 --> 00:01:14,870
And in one study,
babies either saw

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00:01:14,870 --> 00:01:18,110
a plane that was inclined
downward, the hand released it,

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00:01:18,110 --> 00:01:22,250
and it rolled downward with
the natural acceleration,

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00:01:22,250 --> 00:01:26,660
or the plane was inclined
upward, the hand released it,

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00:01:26,660 --> 00:01:29,660
and it rolled
upward, decelerating.

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00:01:29,660 --> 00:01:30,470
OK?

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00:01:30,470 --> 00:01:32,090
We studied this
in adults as well,

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00:01:32,090 --> 00:01:34,490
and for adults, adults
reported that it

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00:01:34,490 --> 00:01:37,107
looked like this hand
set the ball in motion.

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00:01:37,107 --> 00:01:38,690
In fact, to control
the motion better,

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00:01:38,690 --> 00:01:42,980
there was a sling shot apparatus
that actually set it in motion.

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00:01:42,980 --> 00:01:46,250
But it underwent what looked
like a natural deceleration

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00:01:46,250 --> 00:01:51,959
from the point at which the hand
released it and as it rose up.

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00:01:51,959 --> 00:01:53,750
Half the babies were
bored with this event,

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00:01:53,750 --> 00:01:55,490
and half were bored with that.

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00:01:55,490 --> 00:01:59,270
And then, at test, we
switched the direction

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00:01:59,270 --> 00:02:03,140
of the orientation
of the ramp so

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00:02:03,140 --> 00:02:06,140
that if babies had been seeing
something move downward, now

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00:02:06,140 --> 00:02:09,110
they were seeing events
in which it moved upward.

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00:02:09,110 --> 00:02:10,889
And in one of those
two events, it

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00:02:10,889 --> 00:02:13,010
underwent the
natural acceleration

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00:02:13,010 --> 00:02:16,620
that adults would
expect, which is to say,

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00:02:16,620 --> 00:02:19,670
a change in the motion that the
infants had previously seen.

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00:02:19,670 --> 00:02:22,100
So these guys saw this
thing rolling downward

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00:02:22,100 --> 00:02:23,360
and accelerating.

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00:02:23,360 --> 00:02:25,100
And here in the
natural event, they're

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00:02:25,100 --> 00:02:27,200
seeing something that's
being propelled upward,

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00:02:27,200 --> 00:02:28,610
and it's decelerating.

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00:02:28,610 --> 00:02:29,840
OK?

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00:02:29,840 --> 00:02:33,080
In this event, they saw
the same motion pattern

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00:02:33,080 --> 00:02:37,160
that they saw before, so if
they saw speeding up here,

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00:02:37,160 --> 00:02:41,720
they saw speeding up here,
contrary to effects of gravity

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00:02:41,720 --> 00:02:42,620
on object motion.

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00:02:42,620 --> 00:02:43,160
OK.

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00:02:43,160 --> 00:02:44,720
So the question
was, if the babies

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00:02:44,720 --> 00:02:46,550
were sensitive to
effects of gravity,

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they should look longer
when the thing accelerates,

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you know, speeds up
as it's moving upward

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00:02:51,610 --> 00:02:54,369
than they do when it slows
down as it's moving upward.

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00:02:54,369 --> 00:02:56,660
On the other hand, if they're
not sensitive to gravity,

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00:02:56,660 --> 00:02:59,060
and they're just
representing these events

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as speeding up or
slowing down, they

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might show the opposite pattern.

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OK?

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00:03:03,080 --> 00:03:05,960
And that's actually what
we found in both conditions

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00:03:05,960 --> 00:03:06,710
of that study.

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00:03:06,710 --> 00:03:11,690
At five months of age, babies
showed the pattern opposite

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00:03:11,690 --> 00:03:15,440
to what adults would
expect, as if they thought

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00:03:15,440 --> 00:03:17,480
an object that speeds
up in the beginning

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00:03:17,480 --> 00:03:20,810
is going to continue speeding up
irrespective of the orientation

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00:03:20,810 --> 00:03:23,180
of that plane, with
respect to gravity, OK?

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00:03:23,180 --> 00:03:28,090
So failure at five months,
success at seven months.

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00:03:28,090 --> 00:03:29,870
At seven months,
we get a reversal,

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and they flip in their
looking times here.

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00:03:33,930 --> 00:03:36,470
Well, we thought,
maybe the 5-month-olds

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will succeed at a simpler task.

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Suppose we start
out just showing

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00:03:40,550 --> 00:03:42,500
them a flat surface
and constant speed,

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00:03:42,500 --> 00:03:46,850
so we're not engendering
any expectation

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that this object is going
to speed up over time

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or slow down over time.

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00:03:50,090 --> 00:03:51,680
They're just seeing
a constant motion,

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00:03:51,680 --> 00:03:55,040
and then they get
tested with events

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00:03:55,040 --> 00:03:57,260
in which the object is
placed either at the top

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00:03:57,260 --> 00:03:58,970
or at the bottom of this ramp.

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00:03:58,970 --> 00:04:01,490
It's released, and it
speeds up in both cases.

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00:04:01,490 --> 00:04:06,080
In that case, will they view
this motion as more natural

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00:04:06,080 --> 00:04:08,330
and look longer at that one?

95
00:04:08,330 --> 00:04:11,060
Or, you might ask, would they
show the opposite pattern

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00:04:11,060 --> 00:04:14,060
[AUDIO OUT] if these events
are difficult for them,

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00:04:14,060 --> 00:04:15,320
show the opposite pattern?

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00:04:15,320 --> 00:04:17,089
What they actually
showed was absolutely

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00:04:17,089 --> 00:04:20,180
no expectation, the
5-month-olds, in that case.

100
00:04:20,180 --> 00:04:21,170
OK?

101
00:04:21,170 --> 00:04:24,770
They seemed utterly
uncommitted as to whether it

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00:04:24,770 --> 00:04:27,020
was more natural for the
thing to be moving downward

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00:04:27,020 --> 00:04:29,270
than to be moving
upward after seeing

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00:04:29,270 --> 00:04:32,270
it move on this flat surface.

105
00:04:32,270 --> 00:04:37,850
Then, at seven months, kids
responded as adults would.

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00:04:37,850 --> 00:04:40,280
Then we thought, maybe there's
just a problem with video.

107
00:04:40,280 --> 00:04:43,700
Maybe kids don't understand
that vertical in a video

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00:04:43,700 --> 00:04:46,082
corresponds to vertical
in the real world.

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00:04:46,082 --> 00:04:47,540
So we just ran a
control experiment

110
00:04:47,540 --> 00:04:50,000
to see if that was true,
by familiarizing kids

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00:04:50,000 --> 00:04:51,770
with downward motion
in the real world

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00:04:51,770 --> 00:04:54,070
and then presenting those
same two test events.

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00:04:54,070 --> 00:04:57,237
And now they showed the
pattern that adults would show.

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00:04:57,237 --> 00:04:59,570
That's not showing any knowledge
here, it's just saying,

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00:04:59,570 --> 00:05:01,570
yeah, they can distinguish
downward from upward,

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00:05:01,570 --> 00:05:03,650
and they can relate
real events to video.

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00:05:03,650 --> 00:05:07,280
But they don't seem to have any
prior expectation that objects

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00:05:07,280 --> 00:05:11,090
will move downward when they're
rolling on an inclined plane.

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00:05:11,090 --> 00:05:13,790
And all these things seem to
develop between five and seven

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00:05:13,790 --> 00:05:15,200
months, which I
think provides us

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00:05:15,200 --> 00:05:18,625
with an interesting window for
asking what's developing here.

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00:05:18,625 --> 00:05:20,330
One possibility is
what's developing

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00:05:20,330 --> 00:05:21,800
is something very local.

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00:05:21,800 --> 00:05:24,020
But I don't think
so, because there's

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00:05:24,020 --> 00:05:28,160
another change also occurring
between five and seven

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00:05:28,160 --> 00:05:30,967
months in what looks like
a very similar situation.

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00:05:30,967 --> 00:05:33,050
These are experiments that
were conducted in Renée

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00:05:33,050 --> 00:05:36,620
Baillargeon's lab, where she did
these very simple studies where

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00:05:36,620 --> 00:05:38,600
you'd have a single
object in an array,

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00:05:38,600 --> 00:05:41,060
and then a hand would come
in holding another object

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00:05:41,060 --> 00:05:42,740
and place it on that array.

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And in that top study, she
compares infants' reactions

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when the hand places the object
on top of the box, releases it,

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00:05:49,820 --> 00:05:51,890
and it stays there,
versus places

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00:05:51,890 --> 00:05:54,710
the object on the side
of the box, releases it,

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00:05:54,710 --> 00:05:55,970
and it stays there.

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00:05:55,970 --> 00:05:57,290
OK?

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00:05:57,290 --> 00:05:58,880
Now, if you're a
3-month-old infant,

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00:05:58,880 --> 00:06:00,800
you are equally happy
with those two events.

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00:06:00,800 --> 00:06:02,690
You do not look
differentially at them.

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00:06:02,690 --> 00:06:05,180
But by five months, infants do.

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00:06:05,180 --> 00:06:09,710
They look longer when the object
seems to be stably supported

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00:06:09,710 --> 00:06:12,500
by the side of the box, than
when it's stably supported

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00:06:12,500 --> 00:06:14,160
by the top of the box.

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00:06:14,160 --> 00:06:18,620
But then she goes on
and asks, do infants

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00:06:18,620 --> 00:06:20,950
make distinctions among
objects that are stably

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00:06:20,950 --> 00:06:22,100
supported from below?

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00:06:22,100 --> 00:06:24,725
As, by the way, they were in all
those studies with the rolling

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00:06:24,725 --> 00:06:26,319
on the ramps, right?

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00:06:26,319 --> 00:06:27,860
Do they make the
kind of distinctions

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that we would make
based on the mass

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of the object, the physical
force on the object,

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00:06:31,610 --> 00:06:32,180
and so forth?

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00:06:32,180 --> 00:06:34,382
And to get at that,
she did a second study

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00:06:34,382 --> 00:06:35,840
where she has a
box, and she either

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00:06:35,840 --> 00:06:38,540
places it in the middle
of the top box or way

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00:06:38,540 --> 00:06:41,270
off to the side where we
would expect it to fall, OK,

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00:06:41,270 --> 00:06:42,920
not to be stably supported.

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00:06:42,920 --> 00:06:45,650
7-month-olds get that
right, 5-month-olds do not.

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So across these
different situations,

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it looks like we have
this developmental change

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00:06:49,580 --> 00:06:52,230
in what infants know.

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00:06:52,230 --> 00:06:55,320
I mean, I think these studies
raise a lot of questions

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00:06:55,320 --> 00:06:57,690
that they don't answer
about what infants are

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00:06:57,690 --> 00:06:59,887
learning over this time period.

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I'm excited about
that because I think

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they also give us a method for
addressing those questions.

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00:07:06,080 --> 00:07:06,990
OK.

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00:07:06,990 --> 00:07:11,475
And Tomer has been working
on chasing that [AUDIO OUT],,

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which would be great.

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00:07:12,560 --> 00:07:13,170
OK.

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00:07:13,170 --> 00:07:15,697
So I've been asked
already by a bunch of you,

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00:07:15,697 --> 00:07:18,030
what happens at the very
beginning of visual experience?

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00:07:18,030 --> 00:07:19,304
I do have some slides on that.

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I do want us to take
a break, but let me

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00:07:20,970 --> 00:07:24,460
go through them very quickly.

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00:07:24,460 --> 00:07:27,420
There's been a little bit
done with newborn infants,

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00:07:27,420 --> 00:07:30,870
and where they've been
studied under conditions where

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00:07:30,870 --> 00:07:34,620
we are confident that they're
able to see what they're

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00:07:34,620 --> 00:07:36,000
being presented with.

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00:07:36,000 --> 00:07:37,840
It looks as if some of these--

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00:07:37,840 --> 00:07:40,476
there's evidence for these
abilities in newborns,

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00:07:40,476 --> 00:07:41,850
but most of the
things I told you

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00:07:41,850 --> 00:07:44,220
about have not been
tested in newborn infants

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00:07:44,220 --> 00:07:46,350
and would be really
hard to test in them.

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00:07:46,350 --> 00:07:49,410
But fortunately, humans
aren't the only animals

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00:07:49,410 --> 00:07:53,190
that have to be able to
find the objects in a scene

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00:07:53,190 --> 00:07:54,690
and track them through time.

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00:07:54,690 --> 00:07:57,030
Other animals do that as well.

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00:07:57,030 --> 00:08:01,260
And many animals seem to
succeed at representing objects

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00:08:01,260 --> 00:08:03,840
under the conditions
where infants succeed.

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00:08:03,840 --> 00:08:05,970
The big problem we
have with animal models

193
00:08:05,970 --> 00:08:07,590
is that in many
cases, the animals

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00:08:07,590 --> 00:08:09,510
are way more competent
than the infants.

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00:08:09,510 --> 00:08:11,940
And they succeed in cases
where infants would fail.

196
00:08:11,940 --> 00:08:12,540
OK?

197
00:08:12,540 --> 00:08:14,081
But at least where
they succeed where

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00:08:14,081 --> 00:08:15,750
infants succeed, we
can ask, what would

199
00:08:15,750 --> 00:08:17,400
happen with controlled rearing?

200
00:08:17,400 --> 00:08:20,110
And can we at least
get an existence proof

201
00:08:20,110 --> 00:08:22,680
that in a mechanism of the
sort, that the abilities

202
00:08:22,680 --> 00:08:24,930
that we see in infants
can be performed

203
00:08:24,930 --> 00:08:29,040
by some nervous system
on first encounters

204
00:08:29,040 --> 00:08:32,100
with visible objects
and types of events

205
00:08:32,100 --> 00:08:34,620
that it's now being
asked to reason about?

206
00:08:34,620 --> 00:08:38,510
So this has been done with
controlled reared experiments.

207
00:08:38,510 --> 00:08:40,590
I'm going to talk
about just a few,

208
00:08:40,590 --> 00:08:42,659
show you the results of
just a few experiments

209
00:08:42,659 --> 00:08:44,250
that were done on chicks.

210
00:08:44,250 --> 00:08:46,140
Chicks are being
used a lot lately

211
00:08:46,140 --> 00:08:50,580
because they grow up pretty
quickly, they're easy to raise,

212
00:08:50,580 --> 00:08:54,930
and they show this innate
behavior toward objects.

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00:08:54,930 --> 00:08:56,610
That gives us a nice
indicator, which

214
00:08:56,610 --> 00:08:59,010
is in some ways a little bit
like preferential looking,

215
00:08:59,010 --> 00:09:01,470
though opposite in sign.

216
00:09:01,470 --> 00:09:04,532
They imprint if you show
them an object repeatedly,

217
00:09:04,532 --> 00:09:06,240
and a chick has been
isolated, so there's

218
00:09:06,240 --> 00:09:09,930
no other chicks or hens
around in its environment.

219
00:09:09,930 --> 00:09:13,170
The object is the only
moving object they see.

220
00:09:13,170 --> 00:09:18,720
They will imprint to it,
treat it like another--

221
00:09:18,720 --> 00:09:22,680
behave as they would with
their mom, were she there.

222
00:09:22,680 --> 00:09:25,080
And in particular, if
you then take the chick

223
00:09:25,080 --> 00:09:27,180
and put them in a
novel environment

224
00:09:27,180 --> 00:09:28,890
where they're a
little bit stressed,

225
00:09:28,890 --> 00:09:31,100
they will tend to
approach that object.

226
00:09:31,100 --> 00:09:35,130
So this has the same
logic as looking longer

227
00:09:35,130 --> 00:09:35,910
at a novel thing.

228
00:09:35,910 --> 00:09:38,130
You have a selective
approach to a familiar thing,

229
00:09:38,130 --> 00:09:41,580
and you can now run, on chicks,
the kinds of experiments that

230
00:09:41,580 --> 00:09:44,190
have been run on human infants.

231
00:09:44,190 --> 00:09:46,724
So here is one
imprinted chick to a--

232
00:09:46,724 --> 00:09:48,390
these are experiments
that have actually

233
00:09:48,390 --> 00:09:52,020
been done a while ago, in
some case they're much more

234
00:09:52,020 --> 00:09:55,230
recent, imprint a
chick to a triangle,

235
00:09:55,230 --> 00:09:58,230
and then present them with
a triangle whose center is

236
00:09:58,230 --> 00:10:00,210
missing, either
because it's occluded

237
00:10:00,210 --> 00:10:02,430
or because there's a gap there.

238
00:10:02,430 --> 00:10:03,946
Who's mom in this case?

239
00:10:03,946 --> 00:10:05,820
The one with the occluded
center, not the one

240
00:10:05,820 --> 00:10:07,320
with the gap at the center.

241
00:10:07,320 --> 00:10:07,980
OK?

242
00:10:07,980 --> 00:10:09,990
Consistent with
findings with infants

243
00:10:09,990 --> 00:10:14,250
in one way, these chicks
are perceiving occlusion,

244
00:10:14,250 --> 00:10:16,350
but they're doing
better than the infants.

245
00:10:16,350 --> 00:10:18,944
This works when the objects
move behind the occluder.

246
00:10:18,944 --> 00:10:20,610
If you move objects
behind the occluder,

247
00:10:20,610 --> 00:10:22,260
you get all the same
kind of motion effects

248
00:10:22,260 --> 00:10:23,880
that I was talking
about with infants.

249
00:10:23,880 --> 00:10:25,990
But it also works if the
object is stationary.

250
00:10:25,990 --> 00:10:30,160
So the chicks are better than
the infants in that case.

251
00:10:30,160 --> 00:10:31,800
What about object permanence?

252
00:10:31,800 --> 00:10:33,810
Here's a task that
babies can't solve

253
00:10:33,810 --> 00:10:36,390
until they're 12 months old--

254
00:10:36,390 --> 00:10:40,950
well, eight months in this
case, 12 months in this case--

255
00:10:40,950 --> 00:10:43,420
that chicks solved
the first time

256
00:10:43,420 --> 00:10:47,560
they're presented with an
imprinted object that moves out

257
00:10:47,560 --> 00:10:48,060
of you.

258
00:10:48,060 --> 00:10:49,976
I should have said that
on the previous slide.

259
00:10:49,976 --> 00:10:53,730
The chicks never saw occlusion
until the imprinting test.

260
00:10:53,730 --> 00:10:57,750
Here, they're imprinted to mom
on the first two days of life,

261
00:10:57,750 --> 00:10:59,970
but there's no other
surfaces in the environment,

262
00:10:59,970 --> 00:11:02,610
so they never see her
occluded by another surface.

263
00:11:02,610 --> 00:11:05,410
Maybe they see her occluded by
their own wing or something,

264
00:11:05,410 --> 00:11:08,070
but not by other objects
in the environment.

265
00:11:08,070 --> 00:11:08,940
OK.

266
00:11:08,940 --> 00:11:10,050
There's two screens there.

267
00:11:10,050 --> 00:11:12,210
A chick is restrained
in a Plexiglas box

268
00:11:12,210 --> 00:11:15,060
and sees mom disappear
behind one of the screens.

269
00:11:15,060 --> 00:11:19,350
They will go and search
behind that screen for her.

270
00:11:19,350 --> 00:11:21,570
Only at 12 months
do human infants

271
00:11:21,570 --> 00:11:23,130
solve the following problem.

272
00:11:23,130 --> 00:11:25,380
Mom has disappeared
behind and been

273
00:11:25,380 --> 00:11:28,440
found behind this screen
five times in a row.

274
00:11:28,440 --> 00:11:31,590
Now she goes there,
where will chicks search?

275
00:11:31,590 --> 00:11:34,260
A baby, until 12 months, will
search behind the first place

276
00:11:34,260 --> 00:11:37,254
where she was hidden, where
they found her in the past.

277
00:11:37,254 --> 00:11:40,770
A chick is more like
a 12-month-old baby,

278
00:11:40,770 --> 00:11:42,101
shows the more mature pattern.

279
00:11:42,101 --> 00:11:43,350
He goes where mom actually is.

280
00:11:43,350 --> 00:11:44,970
AUDIENCE: Are these
images or actual moms?

281
00:11:44,970 --> 00:11:46,386
LIZ SPELKE: These
are actual moms.

282
00:11:46,386 --> 00:11:48,480
This is imprinting
to either a ping pong

283
00:11:48,480 --> 00:11:51,620
ball in some of these studies
or a cylinder in other studies,

284
00:11:51,620 --> 00:11:53,600
dangles on a wire during
the imprinting period

285
00:11:53,600 --> 00:11:55,190
so you can see that it moves.

286
00:11:55,190 --> 00:11:57,740
It moves here, and
it kind of dangles

287
00:11:57,740 --> 00:12:00,061
and moves behind one
screen or another screen.

288
00:12:00,061 --> 00:12:02,060
And then the chick is
released, and the question

289
00:12:02,060 --> 00:12:03,325
is where will the chick go?

290
00:12:03,325 --> 00:12:03,825
Yeah.

291
00:12:03,825 --> 00:12:06,249
AUDIENCE: Are
these other chicks?

292
00:12:06,249 --> 00:12:07,790
LIZ SPELKE: I think
they imprint them

293
00:12:07,790 --> 00:12:09,470
for two days post hatching.

294
00:12:09,470 --> 00:12:11,970
So they're hatched
in an incubator.

295
00:12:11,970 --> 00:12:14,600
In the killer study I'm
going to tell you about,

296
00:12:14,600 --> 00:12:16,280
the incubator's in the dark.

297
00:12:16,280 --> 00:12:18,647
They spend two days in--

298
00:12:18,647 --> 00:12:20,480
I think they spend a
day in the dark getting

299
00:12:20,480 --> 00:12:22,040
used to just walking around.

300
00:12:22,040 --> 00:12:24,080
And then starts the
visual experience,

301
00:12:24,080 --> 00:12:26,150
and it's controlled,
so no occlusion.

302
00:12:26,150 --> 00:12:30,080
But you do see this one object
that they get to imprint you,

303
00:12:30,080 --> 00:12:32,080
and then they later
go toward the object.

304
00:12:32,080 --> 00:12:32,630
OK?

305
00:12:32,630 --> 00:12:39,080
So an existence proof that
such a capacity could exist

306
00:12:39,080 --> 00:12:41,900
doesn't tell us that it does
exist in a young infant,

307
00:12:41,900 --> 00:12:43,310
but it could.

308
00:12:43,310 --> 00:12:45,830
Here's the one that
was done recently,

309
00:12:45,830 --> 00:12:49,850
that's my favorite study
in this series on solidity.

310
00:12:49,850 --> 00:12:55,130
OK, here's a study where the
chick is hatched in the dark

311
00:12:55,130 --> 00:12:57,740
and spends most of the day
for the first three days

312
00:12:57,740 --> 00:12:59,240
of its life in the dark.

313
00:12:59,240 --> 00:13:01,370
But during a certain
period each day,

314
00:13:01,370 --> 00:13:04,415
it's put in a Plexiglas
box with black walls,

315
00:13:04,415 --> 00:13:07,610
a black floor, black ceiling.

316
00:13:07,610 --> 00:13:10,430
And through the Plexiglas,
there is a single object that

317
00:13:10,430 --> 00:13:12,550
dangles that they imprint to.

318
00:13:12,550 --> 00:13:13,160
OK?

319
00:13:13,160 --> 00:13:15,740
Now, they can't
touch the object,

320
00:13:15,740 --> 00:13:18,230
so they never get evidence
whether this object is solid

321
00:13:18,230 --> 00:13:18,730
or not.

322
00:13:18,730 --> 00:13:20,450
They can't peck at it, right?

323
00:13:20,450 --> 00:13:23,270
They can peck, but
they can only peck

324
00:13:23,270 --> 00:13:25,670
at this black surface
that they can't see

325
00:13:25,670 --> 00:13:29,070
or at this transparent surface
that they also can't see.

326
00:13:29,070 --> 00:13:31,857
So they might learn there are
objects in the environment,

327
00:13:31,857 --> 00:13:34,190
but they're not going to have
any visual characteristics

328
00:13:34,190 --> 00:13:36,200
like this guy does.

329
00:13:36,200 --> 00:13:37,670
OK?

330
00:13:37,670 --> 00:13:38,210
All right.

331
00:13:38,210 --> 00:13:44,330
So then after this experience,
the chick stays in this box,

332
00:13:44,330 --> 00:13:47,090
and in that box, sees
a series of events

333
00:13:47,090 --> 00:13:49,820
involving this object.

334
00:13:49,820 --> 00:13:52,530
In the first set of
experiments, the object

335
00:13:52,530 --> 00:13:56,490
moves behind one screen
and then is revealed there,

336
00:13:56,490 --> 00:14:00,600
or moves behind the other screen
and then is revealed there.

337
00:14:00,600 --> 00:14:02,940
In this particular
study, the chick

338
00:14:02,940 --> 00:14:05,130
does not get to go out
to get to that object.

339
00:14:05,130 --> 00:14:07,280
They did a series of studies
before this one where they did,

340
00:14:07,280 --> 00:14:08,738
but in this case
study, they don't.

341
00:14:13,170 --> 00:14:16,620
Then they see a second set
of events where all they see

342
00:14:16,620 --> 00:14:20,940
is mom starts moving toward the
space between the two screens.

343
00:14:20,940 --> 00:14:24,120
Then there, a screen
comes down, so they

344
00:14:24,120 --> 00:14:25,770
can't see what happens next.

345
00:14:25,770 --> 00:14:27,550
And then when the
screen comes up,

346
00:14:27,550 --> 00:14:29,850
she is no longer
visible, but she then

347
00:14:29,850 --> 00:14:32,310
emerges behind either
one screen or the other,

348
00:14:32,310 --> 00:14:34,290
basically teaching
the chicks, in effect,

349
00:14:34,290 --> 00:14:37,290
mom can go behind each
of these two screens,

350
00:14:37,290 --> 00:14:38,970
OK, either of these two screens.

351
00:14:38,970 --> 00:14:40,590
And then comes
the critical test.

352
00:14:40,590 --> 00:14:43,530
In the critical test, mom starts
moving toward the midpoint

353
00:14:43,530 --> 00:14:44,550
of the two screens.

354
00:14:44,550 --> 00:14:47,980
The screen comes down, and
when the screen-- sorry,

355
00:14:47,980 --> 00:14:51,630
the big occluder--
vision is blocked,

356
00:14:51,630 --> 00:14:55,537
and then when that
curtain raises again

357
00:14:55,537 --> 00:14:57,120
and the two screens
are again visible,

358
00:14:57,120 --> 00:14:58,860
they've been rotated backward.

359
00:14:58,860 --> 00:15:02,550
And across a series of studies,
they vary the size of mom

360
00:15:02,550 --> 00:15:05,250
and the degree of
rotation of the screen.

361
00:15:05,250 --> 00:15:07,860
And the question is, will
the chick go to the side

362
00:15:07,860 --> 00:15:12,000
where the screen's rotation is
consistent with a solid object?

363
00:15:12,000 --> 00:15:13,470
And they do.

364
00:15:13,470 --> 00:15:17,430
I want to argue from that that
knowledge of solidity-- well,

365
00:15:17,430 --> 00:15:19,620
knowledge in some
sense-- representations

366
00:15:19,620 --> 00:15:22,620
that accord with solidity
is innate in chicks.

367
00:15:22,620 --> 00:15:24,780
And what I mean by
innate is simply

368
00:15:24,780 --> 00:15:27,330
that it's present and
functional on first encounters

369
00:15:27,330 --> 00:15:29,497
with objects that
exhibit that property.

370
00:15:29,497 --> 00:15:31,080
This chick has not
had the opportunity

371
00:15:31,080 --> 00:15:32,610
to peck at these
objects, or observe

372
00:15:32,610 --> 00:15:35,350
them bumping into each
other, or anything like that.

373
00:15:35,350 --> 00:15:37,890
And the first time they see
this degree of rotation,

374
00:15:37,890 --> 00:15:40,870
they make inferences that are
consistent with that principle.

375
00:15:40,870 --> 00:15:44,490
This doesn't tell us
that human infants do it.

376
00:15:44,490 --> 00:15:46,180
To be convinced
of that, I'd want

377
00:15:46,180 --> 00:15:49,200
to see evidence for this
ability in an animal that's

378
00:15:49,200 --> 00:15:55,210
a much better model for
human object cognition.

379
00:15:55,210 --> 00:15:57,519
Or I'd want to see more
evidence from the chicks

380
00:15:57,519 --> 00:15:59,310
to convince me that,
actually, the chick is

381
00:15:59,310 --> 00:16:01,374
a really good model of
human object cognition.

382
00:16:01,374 --> 00:16:02,790
But I do think it
should encourage

383
00:16:02,790 --> 00:16:06,990
us to start thinking about how
nervous systems could be wired

384
00:16:06,990 --> 00:16:10,610
to exhibit this property in the
absence of specific learning

385
00:16:10,610 --> 00:16:12,830
and experiences with it.

386
00:16:12,830 --> 00:16:18,440
Here are some questions that
we could talk about in the Q&A

387
00:16:18,440 --> 00:16:20,365
later.

388
00:16:20,365 --> 00:16:23,640
I can give you the
one-liner on it.

389
00:16:23,640 --> 00:16:25,290
On the issue of
compositionality,

390
00:16:25,290 --> 00:16:29,640
the question is, do babies
have a laundry list of rules

391
00:16:29,640 --> 00:16:32,040
about how objects
are going to behave,

392
00:16:32,040 --> 00:16:34,830
or are they building some
kind of unitary model

393
00:16:34,830 --> 00:16:38,790
of the world that accords with
certain general properties?

394
00:16:38,790 --> 00:16:41,100
I think the evidence,
starting at least

395
00:16:41,100 --> 00:16:42,330
at eight months of age--

396
00:16:42,330 --> 00:16:43,860
lower than that, we don't know--

397
00:16:43,860 --> 00:16:45,810
but starting at that
age, I think the evidence

398
00:16:45,810 --> 00:16:47,820
favors the second possibility.

399
00:16:47,820 --> 00:16:49,830
It comes primarily from
these beautiful studies

400
00:16:49,830 --> 00:16:53,580
that were conducted by
Susan Carey and her students

401
00:16:53,580 --> 00:16:58,470
and collaborators where
they presented infants

402
00:16:58,470 --> 00:17:01,740
with an event that
violated cohesion.

403
00:17:01,740 --> 00:17:05,400
So this could be a sand pile
that's poured onto a stage,

404
00:17:05,400 --> 00:17:08,790
or a cookie that's
broken into two pieces

405
00:17:08,790 --> 00:17:13,440
before those pieces
are put in boxes,

406
00:17:13,440 --> 00:17:21,089
or a block that falls apart
when it's hit by another block.

407
00:17:21,089 --> 00:17:25,740
And then, she asks, having
seen that this object violated

408
00:17:25,740 --> 00:17:28,410
this property, do they
expect it to accord

409
00:17:28,410 --> 00:17:30,660
with the other properties?

410
00:17:30,660 --> 00:17:33,120
And the answer is
no, they don't.

411
00:17:33,120 --> 00:17:33,690
OK?

412
00:17:33,690 --> 00:17:37,620
So for example, if
you've seen, there's--

413
00:17:37,620 --> 00:17:40,500
in that causality study where
an object moves behind a screen,

414
00:17:40,500 --> 00:17:42,330
and then another
thing starts to move--

415
00:17:42,330 --> 00:17:45,270
if instead of starting
to move, it falls apart--

416
00:17:45,270 --> 00:17:48,660
it violates cohesion,
falls apart--

417
00:17:48,660 --> 00:17:51,890
infants no longer expect
the first object to hit it.

418
00:17:51,890 --> 00:17:53,250
OK?

419
00:17:53,250 --> 00:17:55,086
Maybe it fell apart
on its own, OK?

420
00:17:55,086 --> 00:17:56,460
They don't assume
that it's going

421
00:17:56,460 --> 00:17:58,650
to behave like an object
in other respects.

422
00:17:58,650 --> 00:18:01,680
They also don't assume that sand
piles will move continuously,

423
00:18:01,680 --> 00:18:04,650
that they won't pass
through surfaces,

424
00:18:04,650 --> 00:18:08,280
that a cookie that is
broken in two-- if you have

425
00:18:08,280 --> 00:18:10,980
two cookies in one box and one
cookie in the other, the babies

426
00:18:10,980 --> 00:18:11,965
crawl to the two.

427
00:18:11,965 --> 00:18:14,340
But if you have one large
cookie, and you break it in two

428
00:18:14,340 --> 00:18:16,840
and put it in one box, they're
neutral between those two

429
00:18:16,840 --> 00:18:17,340
options.

430
00:18:17,340 --> 00:18:17,871
OK?

431
00:18:17,871 --> 00:18:20,370
So it looks like the system is
acting like an interconnected

432
00:18:20,370 --> 00:18:22,310
whole.

433
00:18:22,310 --> 00:18:25,320
What the babies learn about one
aspect of an object's behavior

434
00:18:25,320 --> 00:18:28,410
bears on the inferences they
make about other aspects

435
00:18:28,410 --> 00:18:30,330
of its behavior.

436
00:18:30,330 --> 00:18:33,060
The final thing I want
to end with that I think

437
00:18:33,060 --> 00:18:35,730
makes this point
is very recent work

438
00:18:35,730 --> 00:18:38,370
that was conducted
by Lisa Feigenson--

439
00:18:38,370 --> 00:18:41,070
that I think Laura Schulz
may talk about as well.

440
00:18:41,070 --> 00:18:45,510
Josh mentioned it last Friday,
but didn't really describe it--

441
00:18:45,510 --> 00:18:48,660
that I think suggests that at
least at the end of infancy--

442
00:18:48,660 --> 00:18:52,666
and again, we don't know
what's happening earlier--

443
00:18:52,666 --> 00:18:54,040
infants' understanding
of objects

444
00:18:54,040 --> 00:18:57,850
isn't only forming an
interconnected whole,

445
00:18:57,850 --> 00:19:01,060
but it centers on abstract
notions about the causes

446
00:19:01,060 --> 00:19:04,060
of object motions.

447
00:19:04,060 --> 00:19:08,560
So these are studies that
picked up on some old findings

448
00:19:08,560 --> 00:19:10,390
from a variety of labs.

449
00:19:10,390 --> 00:19:12,680
Here's one that
Baillargeon had worked on,

450
00:19:12,680 --> 00:19:14,920
and I did studies on it
as well, where infants

451
00:19:14,920 --> 00:19:21,080
see an object that's moving in
an array that has two barriers,

452
00:19:21,080 --> 00:19:24,486
but the barriers are
mostly hidden by a screen,

453
00:19:24,486 --> 00:19:26,110
and the object moves
so that it's fully

454
00:19:26,110 --> 00:19:27,160
hidden by the screen.

455
00:19:27,160 --> 00:19:29,590
The question is, where
will it come to rest?

456
00:19:29,590 --> 00:19:31,365
Looking time studies
say babies expect

457
00:19:31,365 --> 00:19:34,240
it to come to rest at the
first barrier in its path.

458
00:19:34,240 --> 00:19:37,120
They look longer if they find
it when the screen is raised

459
00:19:37,120 --> 00:19:40,440
behind the second barrier, as if
it passed through that surface

460
00:19:40,440 --> 00:19:42,770
in its path, a
solidity violation.

461
00:19:42,770 --> 00:19:44,770
Here's another study that
Baillargeon and others

462
00:19:44,770 --> 00:19:47,650
have studied showing that
by three months of age,

463
00:19:47,650 --> 00:19:50,890
infants expect objects to fall
in the absence of support.

464
00:19:50,890 --> 00:19:54,340
If you push a
truck along a block

465
00:19:54,340 --> 00:19:57,730
so that it stops, but under
conditions where it stops, when

466
00:19:57,730 --> 00:20:01,000
it gets to the end of the block
or continues off the block

467
00:20:01,000 --> 00:20:04,750
and doesn't fall, infants look
longer in the latter case.

468
00:20:04,750 --> 00:20:07,324
And what Feigenson
asked is, suppose

469
00:20:07,324 --> 00:20:09,490
we don't let look infants
look as long as they want.

470
00:20:09,490 --> 00:20:11,170
Suppose we limit
their looking time

471
00:20:11,170 --> 00:20:14,020
to just a couple of seconds,
so they've looked equally

472
00:20:14,020 --> 00:20:15,680
at these two outcomes.

473
00:20:15,680 --> 00:20:17,950
What is their internal state?

474
00:20:17,950 --> 00:20:21,430
Are they just bewildered in
the case where the object did

475
00:20:21,430 --> 00:20:23,380
something impossible?

476
00:20:23,380 --> 00:20:27,310
Or are they seeking
to understand

477
00:20:27,310 --> 00:20:28,750
what's happening in the world?

478
00:20:28,750 --> 00:20:30,610
Is this a learning
signal for them?

479
00:20:30,610 --> 00:20:32,719
So she did two experiments--

480
00:20:32,719 --> 00:20:33,760
actually, more than two--

481
00:20:33,760 --> 00:20:36,460
but asked two questions
with experiments.

482
00:20:36,460 --> 00:20:39,820
One question was,
suppose after showing

483
00:20:39,820 --> 00:20:43,390
this event, or this event,
or this, or this one,

484
00:20:43,390 --> 00:20:45,790
after showing an event where
an object behaves naturally

485
00:20:45,790 --> 00:20:48,880
versus apparently
unnaturally, you now

486
00:20:48,880 --> 00:20:51,520
teach infants in effect, try
to teach infants in effect

487
00:20:51,520 --> 00:20:53,210
some new property of the object.

488
00:20:53,210 --> 00:20:54,940
So you pick the object
up and squeak it.

489
00:20:54,940 --> 00:20:56,356
And the question
is, do the babies

490
00:20:56,356 --> 00:20:58,900
learn that the object
makes that sound?

491
00:20:58,900 --> 00:21:04,150
And what she finds is that
the infants learn much more

492
00:21:04,150 --> 00:21:07,750
consistently about the object
whose previous behavior was

493
00:21:07,750 --> 00:21:10,600
unpredicted than about the
object whose previous behavior

494
00:21:10,600 --> 00:21:11,550
was predictable.

495
00:21:11,550 --> 00:21:12,275
OK.

496
00:21:12,275 --> 00:21:14,650
I think this is both good news
and bad news about all the

497
00:21:14,650 --> 00:21:16,811
looking time methods I've
been telling you about.

498
00:21:16,811 --> 00:21:18,310
The good news is
looking time really

499
00:21:18,310 --> 00:21:21,040
does seem, when you let babies
look for as long as they want,

500
00:21:21,040 --> 00:21:23,620
it really does look like
that's tracking what they're

501
00:21:23,620 --> 00:21:27,850
seeking to learn about their
exploration and learning.

502
00:21:27,850 --> 00:21:30,580
The bad news is that when
you restrict looking time

503
00:21:30,580 --> 00:21:32,396
to just a very short
amount of time,

504
00:21:32,396 --> 00:21:34,520
there are many, many things
that could be going on.

505
00:21:34,520 --> 00:21:35,710
They could be attending
a lot, or they

506
00:21:35,710 --> 00:21:36,876
could be attending a little.

507
00:21:36,876 --> 00:21:39,680
It's a very crude measure
that's not telling us that.

508
00:21:39,680 --> 00:21:42,340
But here's a richer measure
suggesting differential

509
00:21:42,340 --> 00:21:44,200
learning in these two cases.

510
00:21:44,200 --> 00:21:46,570
The other study, I
think, is even cooler.

511
00:21:46,570 --> 00:21:49,410
In the other studies, after
showing infants a violation

512
00:21:49,410 --> 00:21:53,110
event, she handed
infants the object,

513
00:21:53,110 --> 00:21:55,220
and allowed them to
explore it, and looked

514
00:21:55,220 --> 00:21:57,730
to see what they would do.

515
00:21:57,730 --> 00:22:00,430
And what she found is that they
do different things depending

516
00:22:00,430 --> 00:22:02,050
on the nature of violation.

517
00:22:02,050 --> 00:22:04,660
So when there was a
solidity violation,

518
00:22:04,660 --> 00:22:07,780
they take the object, and
they bang it on the tray

519
00:22:07,780 --> 00:22:08,500
in front of them.

520
00:22:08,500 --> 00:22:09,220
OK?

521
00:22:09,220 --> 00:22:12,070
In the case of a
support violation,

522
00:22:12,070 --> 00:22:13,990
they take the object,
and they release it.

523
00:22:13,990 --> 00:22:14,550
OK?

524
00:22:14,550 --> 00:22:16,854
So if they're specifically
oriented at 11 months,

525
00:22:16,854 --> 00:22:18,520
and we don't know
what happened earlier,

526
00:22:18,520 --> 00:22:21,590
they're specifically oriented
to expected properties

527
00:22:21,590 --> 00:22:25,030
of the object that could be
relevant to understanding

528
00:22:25,030 --> 00:22:27,940
the apparent violation
that they saw.

529
00:22:27,940 --> 00:22:29,530
To summarize, it
looks like there

530
00:22:29,530 --> 00:22:33,280
is a system that is growing
over the course of infancy,

531
00:22:33,280 --> 00:22:35,380
as it's clear from
all the questions

532
00:22:35,380 --> 00:22:37,630
that we can continue to discuss.

533
00:22:37,630 --> 00:22:40,930
There's a lot we don't
know about this system.

534
00:22:40,930 --> 00:22:43,210
But at no point
in development do

535
00:22:43,210 --> 00:22:45,610
infants seem to
be perceiving just

536
00:22:45,610 --> 00:22:50,920
a two-dimensional, disorganized
world of sensory experiences.

537
00:22:50,920 --> 00:22:54,220
At no point do they seem
oriented to events going on

538
00:22:54,220 --> 00:22:56,830
in the visual field as
opposed to the real world

539
00:22:56,830 --> 00:22:58,414
when you test them
in these situations

540
00:22:58,414 --> 00:22:59,830
where you're asking
them questions

541
00:22:59,830 --> 00:23:01,210
about properties of the world.

542
00:23:01,210 --> 00:23:04,390
They seem to be oriented to
properties of the world itself.

543
00:23:04,390 --> 00:23:05,920
And to start out
already, as early

544
00:23:05,920 --> 00:23:07,960
as we can test them,
in a few cases,

545
00:23:07,960 --> 00:23:10,750
like the center-occluded
objects, that means newborns.

546
00:23:10,750 --> 00:23:13,420
To start out already
with a system which,

547
00:23:13,420 --> 00:23:15,340
although it's radically
different from ours,

548
00:23:15,340 --> 00:23:18,370
we see that most of the
things that we know about,

549
00:23:18,370 --> 00:23:21,580
most of the information we can
get about objects from a scene,

550
00:23:21,580 --> 00:23:23,050
they do not get.

551
00:23:23,050 --> 00:23:27,246
Nevertheless, we're seeing
core skeletal abilities

552
00:23:27,246 --> 00:23:28,870
that we continue to
use throughout life

553
00:23:28,870 --> 00:23:33,250
and that seem to be present to
serve as a basis for learning.

554
00:23:33,250 --> 00:23:35,800
There have been lots of
studies in which infants

555
00:23:35,800 --> 00:23:40,000
have been presented with people
or other self-propelled objects

556
00:23:40,000 --> 00:23:42,610
that have used the same logic
as the studies for looking

557
00:23:42,610 --> 00:23:44,800
at naive physics to get
at something like naive

558
00:23:44,800 --> 00:23:49,150
psychology in infancy, what
they know about object motion.

559
00:23:49,150 --> 00:23:50,920
Most of them are
on babies that are

560
00:23:50,920 --> 00:23:53,505
older than the babies
from the object studies.

561
00:23:53,505 --> 00:23:57,220
Those studies ran mostly up
to about four months of age.

562
00:23:57,220 --> 00:24:00,730
These studies are
starting later than that,

563
00:24:00,730 --> 00:24:02,755
but they give us
a starting point.

564
00:24:02,755 --> 00:24:06,106
And here's one slide that
tries to capture just

565
00:24:06,106 --> 00:24:08,230
about everything that I
think we know about what 6-

566
00:24:08,230 --> 00:24:12,910
to 12-month-old infants,
how they represent agents.

567
00:24:12,910 --> 00:24:15,970
First of all, they represent
people's actions on objects

568
00:24:15,970 --> 00:24:17,840
as directed to goals.

569
00:24:17,840 --> 00:24:20,110
So this is a basic study
that was conducted--

570
00:24:20,110 --> 00:24:22,180
a whole series of
studies, one of many--

571
00:24:22,180 --> 00:24:24,280
conducted by Amanda
Woodward, who

572
00:24:24,280 --> 00:24:26,170
was the advisor for
Jessica Sommerville, who

573
00:24:26,170 --> 00:24:29,717
will be here giving a talk
on Thursday afternoon.

574
00:24:29,717 --> 00:24:32,050
They're very simple studies
in which she presents babies

575
00:24:32,050 --> 00:24:34,600
with two objects side
by side, and then they

576
00:24:34,600 --> 00:24:38,680
see a hand reach out and grasp
one of those two objects.

577
00:24:38,680 --> 00:24:42,070
And the question is, how do
babies represent that action?

578
00:24:42,070 --> 00:24:45,610
Do they represent it as a motion
to a position on the left,

579
00:24:45,610 --> 00:24:48,550
or do they represent
it as an action

580
00:24:48,550 --> 00:24:51,130
with the goal of
obtaining the ball?

581
00:24:51,130 --> 00:24:52,930
And to distinguish
those two possibilities,

582
00:24:52,930 --> 00:24:55,810
she then reverses the
positions of the two objects,

583
00:24:55,810 --> 00:24:57,640
presents the hand
in alternation,

584
00:24:57,640 --> 00:25:00,190
taking a new trajectory
to the old object

585
00:25:00,190 --> 00:25:02,410
versus the old trajectory
to a new object.

586
00:25:02,410 --> 00:25:04,720
And the babies look
longer when the hand goes

587
00:25:04,720 --> 00:25:06,940
to the new object,
suggesting not

588
00:25:06,940 --> 00:25:08,590
that they can't
represent trajectories,

589
00:25:08,590 --> 00:25:11,380
but that they care more about--

590
00:25:11,380 --> 00:25:13,990
bigger news is the agent's goal.

591
00:25:13,990 --> 00:25:16,180
When the goal changes,
that's a bigger change

592
00:25:16,180 --> 00:25:18,460
for the infant than
when the motion simply

593
00:25:18,460 --> 00:25:21,870
changes to a new path
and a new endpoint.

594
00:25:21,870 --> 00:25:25,150
That's at as young as
five months of age.

595
00:25:25,150 --> 00:25:27,880
Then there's been studies
showing that infants' goal

596
00:25:27,880 --> 00:25:32,380
attribution depends on what is
visible from the perspective

597
00:25:32,380 --> 00:25:33,950
of the agent.

598
00:25:33,950 --> 00:25:37,330
So if two objects are present,
and the agent consistently

599
00:25:37,330 --> 00:25:40,990
reaches for one of them,
babies in some sense,

600
00:25:40,990 --> 00:25:44,500
in some poorly-understood
sense, represent that agent

601
00:25:44,500 --> 00:25:46,150
as having a preference
for the object

602
00:25:46,150 --> 00:25:48,920
that they've chosen to go
for over the other object.

603
00:25:48,920 --> 00:25:51,910
But if the object they
didn't go for is occluded,

604
00:25:51,910 --> 00:25:54,430
and there's no evidence
that that agent ever saw it,

605
00:25:54,430 --> 00:25:56,710
they don't make that
preference, inference.

606
00:25:56,710 --> 00:25:58,120
OK?

607
00:25:58,120 --> 00:26:02,030
Third, infants represent
agents as acting efficiently.

608
00:26:02,030 --> 00:26:04,030
And this is true whenever
they're given evidence

609
00:26:04,030 --> 00:26:06,640
for self-propulsion,
whether the object that's

610
00:26:06,640 --> 00:26:08,080
moving in a
self-propelled manner

611
00:26:08,080 --> 00:26:10,160
has the features
of an agent or not.

612
00:26:10,160 --> 00:26:12,460
So with these classic
studies by Gergely

613
00:26:12,460 --> 00:26:15,850
and his collaborators that
continue to the present day,

614
00:26:15,850 --> 00:26:19,180
but started, now, I
guess 20 years ago,

615
00:26:19,180 --> 00:26:21,220
they present infants
with two balls

616
00:26:21,220 --> 00:26:23,650
that engage in self-propelled
motion and even

617
00:26:23,650 --> 00:26:25,420
a little kind of interaction.

618
00:26:25,420 --> 00:26:27,910
And then one of the balls
jumps over a barrier

619
00:26:27,910 --> 00:26:29,200
to get to the other ball.

620
00:26:29,200 --> 00:26:32,230
And across a series of
familiarization trials,

621
00:26:32,230 --> 00:26:33,850
the barrier varies in height.

622
00:26:33,850 --> 00:26:36,100
The jump is appropriately
adapted to it.

623
00:26:36,100 --> 00:26:37,960
And the question
is, what do infants

624
00:26:37,960 --> 00:26:41,980
infer this agent will do when
the barrier is taken away?

625
00:26:41,980 --> 00:26:45,400
Will it engage in one of its
familiar patterns of motion,

626
00:26:45,400 --> 00:26:47,530
or will it engage in a
new pattern of motion

627
00:26:47,530 --> 00:26:49,682
that's more efficient
to get to the object?

628
00:26:49,682 --> 00:26:51,640
And the finding is, they
expect that new motion

629
00:26:51,640 --> 00:26:54,070
and look longer at
the more superficially

630
00:26:54,070 --> 00:26:59,950
familiar but inefficient
indirect action.

631
00:26:59,950 --> 00:27:01,720
Here are my favorite studies.

632
00:27:01,720 --> 00:27:06,640
This is one that Shimon talked
about yesterday afternoon.

633
00:27:06,640 --> 00:27:08,290
He talked about one
version of this.

634
00:27:08,290 --> 00:27:12,130
The original study was
conducted by Sabina Pauen,

635
00:27:12,130 --> 00:27:15,921
and Rebecca Saxe and Susan
Carey did interesting extensions

636
00:27:15,921 --> 00:27:16,420
on it.

637
00:27:16,420 --> 00:27:19,500
It uses the simplest
imaginable method.

638
00:27:19,500 --> 00:27:22,600
They present babies first
with two objects, stationary,

639
00:27:22,600 --> 00:27:25,390
side by side, one
with animate features,

640
00:27:25,390 --> 00:27:28,940
a face and sort of a fuzzy
body, tail-like body,

641
00:27:28,940 --> 00:27:31,880
the other, an inanimate ball.

642
00:27:31,880 --> 00:27:33,997
They're both stationary,
and the objects

643
00:27:33,997 --> 00:27:35,830
were chosen to be about
equally interesting.

644
00:27:35,830 --> 00:27:38,320
The babies look about
half the time at each one.

645
00:27:38,320 --> 00:27:42,070
Then, they see a series of
events in which these two

646
00:27:42,070 --> 00:27:44,620
objects are stuck together
and undergo this very

647
00:27:44,620 --> 00:27:46,460
irregular pattern of motion.

648
00:27:46,460 --> 00:27:48,340
This was actually some
kind of parlor trick

649
00:27:48,340 --> 00:27:49,810
toy that was sold for a while.

650
00:27:49,810 --> 00:27:51,610
They got them started
on this study.

651
00:27:51,610 --> 00:27:54,250
There's a mechanism inside the
ball that's actually propelling

652
00:27:54,250 --> 00:27:55,810
the two objects around.

653
00:27:55,810 --> 00:27:59,170
But the question is,
which of these two objects

654
00:27:59,170 --> 00:28:02,290
does the baby attribute
the motion to?

655
00:28:02,290 --> 00:28:05,290
And to find that out, they
subsequently separated the two

656
00:28:05,290 --> 00:28:08,410
objects again, and ask again,
which one will the infant look

657
00:28:08,410 --> 00:28:09,040
at more?

658
00:28:09,040 --> 00:28:11,020
And after seeing this
motion, the infant

659
00:28:11,020 --> 00:28:13,960
looks more at the one that
has the animate features.

660
00:28:13,960 --> 00:28:16,720
Although both objects
underwent the same motion,

661
00:28:16,720 --> 00:28:20,170
they attribute that motion to
this guy, not the other guy.

662
00:28:20,170 --> 00:28:22,480
It follows then that
they're perceiving

663
00:28:22,480 --> 00:28:25,630
this-- they're representing this
guy as causing the other guy's

664
00:28:25,630 --> 00:28:26,200
motion.

665
00:28:26,200 --> 00:28:26,440
Right?

666
00:28:26,440 --> 00:28:28,780
The other guy is not seen
as causing its own motion.

667
00:28:28,780 --> 00:28:30,610
The motion is being
caused by this guy.

668
00:28:30,610 --> 00:28:33,400
This is at seven months of age.

669
00:28:33,400 --> 00:28:36,766
Now, even stronger evidence
that infants infer causal agents

670
00:28:36,766 --> 00:28:38,140
come from these
beautiful studies

671
00:28:38,140 --> 00:28:40,600
that Rebecca Saxe, and Susan
Carey, and Josh Tenenbaum

672
00:28:40,600 --> 00:28:44,050
conducted 10 years ago
now, that went back

673
00:28:44,050 --> 00:28:45,910
to this efficient
situation where

674
00:28:45,910 --> 00:28:48,370
you see an object
efficiently going over

675
00:28:48,370 --> 00:28:50,650
barriers of variable
heights to get

676
00:28:50,650 --> 00:28:53,590
to a new position on the stage.

677
00:28:53,590 --> 00:28:55,570
The one thing they
added is that the object

678
00:28:55,570 --> 00:28:57,100
is manifestly inanimate.

679
00:28:57,100 --> 00:28:58,064
It's a beanbag.

680
00:28:58,064 --> 00:29:00,730
And the kid had a chance to play
with it before the study began.

681
00:29:00,730 --> 00:29:03,530
They can feel that this
is not an animate object.

682
00:29:03,530 --> 00:29:06,610
So if this isn't
an animate object,

683
00:29:06,610 --> 00:29:09,520
and infants are actively
trying to explain

684
00:29:09,520 --> 00:29:11,560
the motions of
objects that they see,

685
00:29:11,560 --> 00:29:13,750
they're going to need
another kind of explanation.

686
00:29:13,750 --> 00:29:16,210
And what Saxe, Tenenbaum,
and Carey showed

687
00:29:16,210 --> 00:29:18,100
is that infants
infer that there is

688
00:29:18,100 --> 00:29:20,920
an agent, off-screen, on
this side of the screen, that

689
00:29:20,920 --> 00:29:22,690
set that object in motion.

690
00:29:22,690 --> 00:29:26,020
And they show that by
their relative looking time

691
00:29:26,020 --> 00:29:30,460
to an event where a hand comes
in on that side of the screen,

692
00:29:30,460 --> 00:29:33,880
which is consistent with that
causal attribution, versus

693
00:29:33,880 --> 00:29:36,880
it comes in on the other side,
which is inconsistent with it.

694
00:29:36,880 --> 00:29:39,460
And really, a
pretty manipulation.

695
00:29:39,460 --> 00:29:42,790
If in fact babies are making
causal attributions here,

696
00:29:42,790 --> 00:29:44,860
then you ought to be
able to screen them off.

697
00:29:44,860 --> 00:29:47,770
If you make a simple
change to the method,

698
00:29:47,770 --> 00:29:51,880
you show evidence that actually,
this object is animate.

699
00:29:51,880 --> 00:29:54,642
If it is animate, then you don't
need to infer another cause.

700
00:29:54,642 --> 00:29:56,350
So they ran that study
as well and showed

701
00:29:56,350 --> 00:29:58,224
that when you change
from an inanimate object

702
00:29:58,224 --> 00:30:00,740
to an animate one, you no
longer get this effect.

703
00:30:00,740 --> 00:30:01,240
OK?

704
00:30:01,240 --> 00:30:03,865
So it really looks like they're
seeking to explain these events

705
00:30:03,865 --> 00:30:06,010
and doing so in accord
with the principle

706
00:30:06,010 --> 00:30:08,110
that agents can cause not
only their own motion,

707
00:30:08,110 --> 00:30:10,510
but also can make changes
in the world, cause motions

708
00:30:10,510 --> 00:30:12,130
and other changes in objects.

709
00:30:12,130 --> 00:30:13,780
And a final study
that shows this,

710
00:30:13,780 --> 00:30:17,500
I told you that if a truck goes
behind a screen toward a box,

711
00:30:17,500 --> 00:30:20,020
and then the box
subsequently collapses,

712
00:30:20,020 --> 00:30:23,690
babies do not infer that
the truck hit the box.

713
00:30:23,690 --> 00:30:24,190
OK?

714
00:30:24,190 --> 00:30:26,636
Collapsing takes this
outside the domain

715
00:30:26,636 --> 00:30:28,510
of physical reasoning
for those young babies.

716
00:30:28,510 --> 00:30:29,110
OK?

717
00:30:29,110 --> 00:30:31,510
But suppose instead of a
truck going behind that-- this

718
00:30:31,510 --> 00:30:32,950
is work by Susan Carey as well.

719
00:30:32,950 --> 00:30:36,280
Sorry, I should have put it
on here, Muentener and Carey.

720
00:30:36,280 --> 00:30:39,700
If instead of a truck, a
hand goes behind that screen,

721
00:30:39,700 --> 00:30:43,000
now they infer that the
hand did contact the object.

722
00:30:43,000 --> 00:30:43,570
OK?

723
00:30:43,570 --> 00:30:46,192
So hands can make things
move, and they not only

724
00:30:46,192 --> 00:30:47,650
can make things
move, they can make

725
00:30:47,650 --> 00:30:49,816
things do all sorts of
things that objects otherwise

726
00:30:49,816 --> 00:30:52,270
won't do, like fall apart, OK?

727
00:30:52,270 --> 00:30:52,910
All right.

728
00:30:52,910 --> 00:30:56,320
So one problem, as I said,
with all these studies

729
00:30:56,320 --> 00:30:58,810
is that they're all older
infants, many of them

730
00:30:58,810 --> 00:31:03,520
much older infants like 8- and
10-month-olds, just about all

731
00:31:03,520 --> 00:31:06,850
of them 6 months old or older.

732
00:31:06,850 --> 00:31:08,480
And when you test
younger infants,

733
00:31:08,480 --> 00:31:10,550
you get failures on
some of these tasks.

734
00:31:10,550 --> 00:31:13,840
So these goal attribution tasks
work with 5-month-old infants,

735
00:31:13,840 --> 00:31:16,350
but they fail with
3-month-old infants.

736
00:31:16,350 --> 00:31:18,940
3-month-old infants
seem uncommitted as

737
00:31:18,940 --> 00:31:21,460
to where this hand is
going to go once the two

738
00:31:21,460 --> 00:31:26,080
objects exchange locations.

739
00:31:26,080 --> 00:31:28,060
And that raises the question--

740
00:31:28,060 --> 00:31:29,860
to me, the most
interesting question--

741
00:31:29,860 --> 00:31:32,810
what kinds of representations
of agents, if any,

742
00:31:32,810 --> 00:31:36,190
does a younger infant
have before they're

743
00:31:36,190 --> 00:31:39,940
able to act on the
world by manipulating

744
00:31:39,940 --> 00:31:43,360
things, which starts
around five months of age?

745
00:31:43,360 --> 00:31:47,150
And tell you just quickly, two
kinds of studies that I think

746
00:31:47,150 --> 00:31:48,400
get at this--

747
00:31:48,400 --> 00:31:51,250
imperfectly, but
they're getting there.

748
00:31:51,250 --> 00:31:53,620
One is, again, going
back to studies

749
00:31:53,620 --> 00:31:55,540
of controlled reared animals.

750
00:31:55,540 --> 00:31:57,814
Chicks, again, in particular.

751
00:31:57,814 --> 00:31:59,230
There have been
imprinting studies

752
00:31:59,230 --> 00:32:01,510
done where chicks are
raised in the dark,

753
00:32:01,510 --> 00:32:05,140
and all they get to
see are video screens

754
00:32:05,140 --> 00:32:09,250
in which you get two objects
engaging in this simple causal

755
00:32:09,250 --> 00:32:11,410
billiard ball type event.

756
00:32:11,410 --> 00:32:14,570
One object starts to move,
contacts a second object,

757
00:32:14,570 --> 00:32:17,710
and at the point of
contact, it stops moving,

758
00:32:17,710 --> 00:32:19,890
and the other object
starts to move.

759
00:32:19,890 --> 00:32:20,620
OK?

760
00:32:20,620 --> 00:32:22,400
And they see that repeatedly.

761
00:32:22,400 --> 00:32:26,230
And now, OK, I told you that if
chicks are raised in isolation,

762
00:32:26,230 --> 00:32:28,960
but there's a moving object
there, they'll imprint to it.

763
00:32:28,960 --> 00:32:30,790
I was treating the
imprinting object

764
00:32:30,790 --> 00:32:32,650
as just an example of an object.

765
00:32:32,650 --> 00:32:34,800
But of course, the
imprinting object is mom,

766
00:32:34,800 --> 00:32:35,770
and she's an agent.

767
00:32:35,770 --> 00:32:38,500
So it should be a self-propelled
object, really, right?

768
00:32:38,500 --> 00:32:43,030
So given a choice
between these two,

769
00:32:43,030 --> 00:32:45,850
do they selectively imprint
to one over the other?

770
00:32:45,850 --> 00:32:49,550
And the finding is that they do.

771
00:32:49,550 --> 00:32:51,234
The two objects have
different features,

772
00:32:51,234 --> 00:32:53,650
I think, different colors,
maybe different shapes as well.

773
00:32:53,650 --> 00:32:56,140
If you now present one of
them at one end of their cage

774
00:32:56,140 --> 00:32:57,790
and the other at the
other end, they'll

775
00:32:57,790 --> 00:33:01,660
go to object A over object
B as if they saw that

776
00:33:01,660 --> 00:33:04,480
as the object that set the
other object in motion.

777
00:33:04,480 --> 00:33:07,900
But now you could ask, is that
because they see A as causal,

778
00:33:07,900 --> 00:33:09,670
as causing its own motion?

779
00:33:09,670 --> 00:33:12,740
Or is it for other superficial
reasons like A moved first,

780
00:33:12,740 --> 00:33:15,460
or A was moving at the
time of the collision,

781
00:33:15,460 --> 00:33:17,140
and B was stationary?

782
00:33:17,140 --> 00:33:19,600
So they tested for all of
these things one by one,

783
00:33:19,600 --> 00:33:21,520
but this is their killer
experiment, the test

784
00:33:21,520 --> 00:33:23,110
for all of them at once.

785
00:33:23,110 --> 00:33:24,880
They present exactly
the same events.

786
00:33:24,880 --> 00:33:29,440
The only difference is you
don't see A initially at rest

787
00:33:29,440 --> 00:33:31,041
and starting to move.

788
00:33:31,041 --> 00:33:31,540
OK?

789
00:33:31,540 --> 00:33:32,910
You never get to see that.

790
00:33:32,910 --> 00:33:35,000
There are screens on the
two ends of the display,

791
00:33:35,000 --> 00:33:38,860
so all you see is that A enters
the display already in motion

792
00:33:38,860 --> 00:33:42,170
and contacts B. So you have
no evidence as to whether A

793
00:33:42,170 --> 00:33:44,470
is self-propelled
or not, but you

794
00:33:44,470 --> 00:33:47,680
see the two objects interacting
otherwise in the same way.

795
00:33:47,680 --> 00:33:49,760
That makes the effect
completely go away.

796
00:33:49,760 --> 00:33:51,790
I think this is
logically a little

797
00:33:51,790 --> 00:33:53,530
like the studies
with infants where

798
00:33:53,530 --> 00:33:55,630
you show that the thing
is animate or not,

799
00:33:55,630 --> 00:33:57,940
and it effects whether
they expect that there's

800
00:33:57,940 --> 00:33:59,950
an agent there or not.

801
00:33:59,950 --> 00:34:02,680
It suggests that infants
are representing A

802
00:34:02,680 --> 00:34:04,600
as causing its own motion.

803
00:34:04,600 --> 00:34:06,850
They're representing it
as causing B's motions,

804
00:34:06,850 --> 00:34:10,420
so A is a better object
of imprinting than B is.

805
00:34:10,420 --> 00:34:15,824
And all of this can
be abolished if A

806
00:34:15,824 --> 00:34:17,699
isn't seen to have the
first causal property,

807
00:34:17,699 --> 00:34:19,960
they're not
inferring the second.

808
00:34:19,960 --> 00:34:22,780
So it's, again, an existence
proof kind of argument saying,

809
00:34:22,780 --> 00:34:25,540
you can get this kind of system
working in an animal that

810
00:34:25,540 --> 00:34:29,469
hasn't had prior visual
experiences in which they've

811
00:34:29,469 --> 00:34:32,854
seen objects in motion or in
which they themselves have

812
00:34:32,854 --> 00:34:35,270
been-- they haven't had any
other encounters with objects,

813
00:34:35,270 --> 00:34:37,659
so they haven't been able
to move things around.

814
00:34:37,659 --> 00:34:40,360
So that's one way of trying to
get at early representations.

815
00:34:40,360 --> 00:34:43,250
Here's another way
that I hope Sommerville

816
00:34:43,250 --> 00:34:45,850
will talk about
on Thursday night,

817
00:34:45,850 --> 00:34:48,310
because she pioneered this
method with Amanda Woodward

818
00:34:48,310 --> 00:34:51,130
and Amy Needham.

819
00:34:51,130 --> 00:34:54,130
You can give a 3-month-old
infant, who otherwise wouldn't

820
00:34:54,130 --> 00:34:56,770
be reaching for things
for another two months,

821
00:34:56,770 --> 00:35:00,550
you can give them the
ability to pick up objects

822
00:35:00,550 --> 00:35:03,894
by equipping them with mittens
that have Velcro on them

823
00:35:03,894 --> 00:35:05,560
and presenting them
with Velcro objects.

824
00:35:05,560 --> 00:35:09,020
So now they can
make things move.

825
00:35:09,020 --> 00:35:11,650
And when you do that, you
see interesting changes

826
00:35:11,650 --> 00:35:13,940
in their representations
of these events.

827
00:35:13,940 --> 00:35:16,330
So an infant who has
played with an object

828
00:35:16,330 --> 00:35:20,800
while wearing a sticky
mitten, who subsequently looks

829
00:35:20,800 --> 00:35:23,800
at events in which another
person wearing that mitten

830
00:35:23,800 --> 00:35:27,970
reaches for that object
or for another object,

831
00:35:27,970 --> 00:35:30,910
now they look like a
5-month-old and represent

832
00:35:30,910 --> 00:35:33,280
that reaching as goal-directed.

833
00:35:33,280 --> 00:35:35,950
But on the other hand, if
they saw those same events

834
00:35:35,950 --> 00:35:39,080
without the mittens,
they failed.

835
00:35:39,080 --> 00:35:41,500
So that's saying that
the infant's own action

836
00:35:41,500 --> 00:35:46,150
experience can elicit these
action representations.

837
00:35:46,150 --> 00:35:48,820
And it raises, I think, all
sorts of interesting questions

838
00:35:48,820 --> 00:35:52,120
about, do infants have
to learn one by one

839
00:35:52,120 --> 00:35:54,010
what the properties
of agents are?

840
00:35:54,010 --> 00:35:57,100
Or is it possible that
once these representations

841
00:35:57,100 --> 00:35:59,020
of goal-directed
actions are elicited,

842
00:35:59,020 --> 00:36:02,559
we'll see other knowledge
of agents already present?

843
00:36:02,559 --> 00:36:04,600
So let me just give you
one finding that suggests

844
00:36:04,600 --> 00:36:06,100
we might get the second.

845
00:36:06,100 --> 00:36:12,400
This is a study that Amy Skerry
performed rather recently.

846
00:36:12,400 --> 00:36:14,830
She was interested in
this representation

847
00:36:14,830 --> 00:36:17,230
of efficient action
before babies

848
00:36:17,230 --> 00:36:20,390
are able to reach for and
pick up objects themselves.

849
00:36:20,390 --> 00:36:24,800
Do they already represent
the actions of agents

850
00:36:24,800 --> 00:36:27,380
as directed to
goals efficiently?

851
00:36:27,380 --> 00:36:30,100
Did they already expect that
agents will move efficiently

852
00:36:30,100 --> 00:36:32,270
to achieve their goals?

853
00:36:32,270 --> 00:36:36,220
So to get at that, she gave
infants, 3-month-old infants,

854
00:36:36,220 --> 00:36:38,410
sticky mittens experience
with an object where

855
00:36:38,410 --> 00:36:44,830
they got to pick up the
object and then showed them

856
00:36:44,830 --> 00:36:48,460
events in one-- split them
into two different conditions,

857
00:36:48,460 --> 00:36:50,380
and in both conditions,
they see events

858
00:36:50,380 --> 00:36:54,520
in which a person moves on an
indirect path to an object.

859
00:36:54,520 --> 00:36:57,670
In one of the series of events,
there's a barrier in the way,

860
00:36:57,670 --> 00:37:01,270
so that motion is the best way
to get there, probably the only

861
00:37:01,270 --> 00:37:02,709
obvious way to get there.

862
00:37:02,709 --> 00:37:04,750
In the other case, the
barrier is in the display,

863
00:37:04,750 --> 00:37:08,320
but it's out of the way, so
this is not an efficient action.

864
00:37:08,320 --> 00:37:12,240
And then at test, the barrier
is gone in both conditions,

865
00:37:12,240 --> 00:37:15,550
and the person either
moves efficiently or moves

866
00:37:15,550 --> 00:37:16,690
inefficiently.

867
00:37:16,690 --> 00:37:18,820
Now, in this control
condition, the baby

868
00:37:18,820 --> 00:37:20,760
does not expect
efficient action.

869
00:37:20,760 --> 00:37:22,510
But in the condition
where they previously

870
00:37:22,510 --> 00:37:25,060
had the sticky mittens
experience, which presumably

871
00:37:25,060 --> 00:37:28,000
told them that this is
actually the person's goal,

872
00:37:28,000 --> 00:37:30,340
that they're attempting
to get there, once

873
00:37:30,340 --> 00:37:33,190
they have that, what seems
to follow immediately

874
00:37:33,190 --> 00:37:35,856
from that is this
efficiency, this principle

875
00:37:35,856 --> 00:37:37,480
of efficient action,
right, that you'll

876
00:37:37,480 --> 00:37:39,940
move to the goal on the
most direct path possible,

877
00:37:39,940 --> 00:37:42,070
even though you've never
seen that direct path.

878
00:37:42,070 --> 00:37:43,660
And even though
when the infant was

879
00:37:43,660 --> 00:37:46,420
playing with the
object with the mittens

880
00:37:46,420 --> 00:37:49,360
on and picking up objects for
the first time in his life,

881
00:37:49,360 --> 00:37:50,890
there were no barriers present.

882
00:37:50,890 --> 00:37:52,630
They never had to do
anything indirect.

883
00:37:52,630 --> 00:37:55,840
They could always get
that object directly.

884
00:37:55,840 --> 00:37:57,310
Yet they're expecting
direct action

885
00:37:57,310 --> 00:38:02,890
only when they've seen efficient
action in another agent.

886
00:38:02,890 --> 00:38:05,180
OK.

887
00:38:05,180 --> 00:38:08,560
So in summary, it looks like
these abilities are all there

888
00:38:08,560 --> 00:38:11,130
quite early.

889
00:38:11,130 --> 00:38:12,880
They're unlearned,
at least some of them

890
00:38:12,880 --> 00:38:15,160
are unlearned, in chicks.

891
00:38:15,160 --> 00:38:17,500
And they can be
elicited before--

892
00:38:17,500 --> 00:38:20,740
at least some of them can be
elicited before reaching--

893
00:38:20,740 --> 00:38:22,075
develops in young infants.

894
00:38:22,075 --> 00:38:23,950
But infants-- and this
is important, I think,

895
00:38:23,950 --> 00:38:25,900
for what Alia's going
to be talking about--

896
00:38:25,900 --> 00:38:28,180
infants' understanding
of agents is limited.

897
00:38:28,180 --> 00:38:30,550
It's radically limited, just
like their understanding

898
00:38:30,550 --> 00:38:34,120
of inanimate objects is.

899
00:38:34,120 --> 00:38:37,990
And here are a few, I think,
really interesting limits.

900
00:38:37,990 --> 00:38:40,450
Although infants are
sensitive to what's

901
00:38:40,450 --> 00:38:45,190
perceptually
accessible to an agent,

902
00:38:45,190 --> 00:38:49,120
they don't seem to represent
agents as seeing objects.

903
00:38:49,120 --> 00:38:50,570
What do I mean by that?

904
00:38:50,570 --> 00:38:53,470
Well, here's a experiment
with exactly the structure

905
00:38:53,470 --> 00:38:55,410
of the Woodward
reaching experiment.

906
00:38:55,410 --> 00:38:59,020
Two objects present, and
a person acts with respect

907
00:38:59,020 --> 00:39:00,010
to one of them.

908
00:39:00,010 --> 00:39:01,780
But instead of reaching
for one object,

909
00:39:01,780 --> 00:39:03,940
she looks at one
of the two objects.

910
00:39:03,940 --> 00:39:07,060
And now, you ask, after you
exchange the two objects'

911
00:39:07,060 --> 00:39:09,790
positions, do babies
find that she's

912
00:39:09,790 --> 00:39:13,129
doing something newer if she
looks at the other object?

913
00:39:13,129 --> 00:39:14,920
Or do they find she's
doing something newer

914
00:39:14,920 --> 00:39:16,600
if she looks in a
different direction

915
00:39:16,600 --> 00:39:17,850
than she looked in before?

916
00:39:17,850 --> 00:39:18,580
OK?

917
00:39:18,580 --> 00:39:22,630
At 12 months, infants view
looking as object-directed,

918
00:39:22,630 --> 00:39:24,190
by this measure.

919
00:39:24,190 --> 00:39:26,320
Younger than 12
months, they do not.

920
00:39:26,320 --> 00:39:30,400
They don't seem to view the
orientation of the person

921
00:39:30,400 --> 00:39:34,860
as a look that's directed
to one of these two objects,

922
00:39:34,860 --> 00:39:35,950
by that measure.

923
00:39:35,950 --> 00:39:37,550
Now, the age at
which they succeeded,

924
00:39:37,550 --> 00:39:39,070
this is also the
first age at which

925
00:39:39,070 --> 00:39:41,560
infants start to show this
really interesting pattern

926
00:39:41,560 --> 00:39:43,390
in their communication
with other people,

927
00:39:43,390 --> 00:39:45,592
that Mike Tomasello has
written about a lot.

928
00:39:45,592 --> 00:39:47,050
It's the first age
at which they'll

929
00:39:47,050 --> 00:39:51,280
start to alternately
look at objects,

930
00:39:51,280 --> 00:39:53,050
and look at another
person, and attempt

931
00:39:53,050 --> 00:39:56,020
to engage their attention to
the object, by checking back

932
00:39:56,020 --> 00:39:59,170
and forth between looks at the
person and looks at the object,

933
00:39:59,170 --> 00:40:02,080
or by pointing to the object,
or by following another person's

934
00:40:02,080 --> 00:40:02,977
point to an object.

935
00:40:02,977 --> 00:40:05,060
All of that comes in at
the end of the first year.

936
00:40:05,060 --> 00:40:06,820
It's not there earlier.

937
00:40:06,820 --> 00:40:09,640
Younger infants, younger
than about 12 months of age,

938
00:40:09,640 --> 00:40:12,841
don't even seem to expect
that if a person reaches

939
00:40:12,841 --> 00:40:15,340
for one of two objects, they'll
tend to reach for the object

940
00:40:15,340 --> 00:40:16,670
that they were looking at.

941
00:40:16,670 --> 00:40:17,170
OK?

942
00:40:17,170 --> 00:40:19,900
We thought for sure babies would
succeed at that task early.

943
00:40:19,900 --> 00:40:21,400
They don't reliably
succeed at it

944
00:40:21,400 --> 00:40:24,250
until 12 or even
14 months of age.

945
00:40:24,250 --> 00:40:27,070
And finally, babies
attribute first order but not

946
00:40:27,070 --> 00:40:29,170
second order goals to agents.

947
00:40:29,170 --> 00:40:32,050
So if they see an
agent pull on a rake

948
00:40:32,050 --> 00:40:34,030
and then reach for
an object, they

949
00:40:34,030 --> 00:40:36,697
perceive the agent's goal
as the rake, not the object

950
00:40:36,697 --> 00:40:37,780
that they're reaching for.

951
00:40:37,780 --> 00:40:40,570
So very limited representations.

952
00:40:40,570 --> 00:40:44,580
Also, as far as we know, none
of these are unique to humans.

953
00:40:44,580 --> 00:40:46,330
I think this raised
all sorts of questions

954
00:40:46,330 --> 00:40:49,960
that we might want to talk
about in the Q&A later.

955
00:40:49,960 --> 00:40:53,020
What's the relationship between
infants' representations

956
00:40:53,020 --> 00:40:55,330
of agents and their
representations of the things

957
00:40:55,330 --> 00:40:56,770
that agents act on?

958
00:40:56,770 --> 00:41:02,540
Clearly, these should be related
in some interesting ways.

959
00:41:02,540 --> 00:41:05,230
Although, agents can do
things that objects can't do,

960
00:41:05,230 --> 00:41:07,420
like move on their own,
and formulate goals,

961
00:41:07,420 --> 00:41:10,870
and act on things that are
visually accessible to them.

962
00:41:10,870 --> 00:41:13,060
Agents also are objects, right?

963
00:41:13,060 --> 00:41:15,680
And we're subject to all
the constraints on objects.

964
00:41:15,680 --> 00:41:16,911
We can't walk through walls.

965
00:41:16,911 --> 00:41:19,285
If we want to make something
move, we have to contact it.

966
00:41:19,285 --> 00:41:23,320
And babies are sensitive
to those constraints.

967
00:41:23,320 --> 00:41:25,270
And I think this raises
all sorts of questions

968
00:41:25,270 --> 00:41:28,870
that to date, research on
infants hasn't really answered.

969
00:41:28,870 --> 00:41:31,060
Is there some hierarchy
of representations

970
00:41:31,060 --> 00:41:33,340
where you've got all
objects, and then you've

971
00:41:33,340 --> 00:41:36,820
got these especially talented
objects that are agents, right?

972
00:41:36,820 --> 00:41:39,910
Or I think one way Tomer has put
it is maybe we're all agents,

973
00:41:39,910 --> 00:41:41,980
but objects are just
really bad agents, right,

974
00:41:41,980 --> 00:41:44,270
that can't do very much.

975
00:41:44,270 --> 00:41:45,917
That's one possibility.

976
00:41:45,917 --> 00:41:47,500
It's also possible
that these are just

977
00:41:47,500 --> 00:41:48,916
separate systems
at the beginning,

978
00:41:48,916 --> 00:41:52,960
and they have to get
linked together over time.

979
00:41:52,960 --> 00:41:56,630
I think these are all
answerable questions.

980
00:41:56,630 --> 00:41:59,780
I said that babies don't see
looking as directed to objects,

981
00:41:59,780 --> 00:42:06,230
but they do from birth respond
in a pro-social way to looking

982
00:42:06,230 --> 00:42:07,640
that's directed to them.

983
00:42:07,640 --> 00:42:09,680
So an infant will
look longer at someone

984
00:42:09,680 --> 00:42:12,440
whose eyes are directed
to them than someone

985
00:42:12,440 --> 00:42:14,010
whose eyes are looking away.

986
00:42:14,010 --> 00:42:15,260
That's true for human infants.

987
00:42:15,260 --> 00:42:18,020
It's also true for
infant monkeys.

988
00:42:18,020 --> 00:42:20,352
If a monkey is presented
with this display,

989
00:42:20,352 --> 00:42:22,310
and they're over here,
they'll look longer than

990
00:42:22,310 --> 00:42:23,660
if they're over here.

991
00:42:23,660 --> 00:42:25,190
Right?

992
00:42:25,190 --> 00:42:28,130
When they're here, it looks like
that guy is looking at them.

993
00:42:28,130 --> 00:42:30,695
They also, human
and monkey infants

994
00:42:30,695 --> 00:42:39,110
engage in eye-to-eye contact
with adults from birth.

995
00:42:39,110 --> 00:42:41,390
They also, human infants
and monkey infants

996
00:42:41,390 --> 00:42:43,490
tend to imitate the
gestures of other people,

997
00:42:43,490 --> 00:42:46,430
interestingly, only when those
people are looking at them,

998
00:42:46,430 --> 00:42:47,960
not when they close their eyes.

999
00:42:47,960 --> 00:42:52,160
Then they'll imitate them as
you saw in those beautiful films

1000
00:42:52,160 --> 00:42:56,150
that Winrich showed
from the Ferrari group,

1001
00:42:56,150 --> 00:42:59,000
attentive to the person and
then trying to reproduce

1002
00:42:59,000 --> 00:43:00,450
the person's action.

1003
00:43:00,450 --> 00:43:03,020
This has been shown with baby
chimpanzees and baby monkeys

1004
00:43:03,020 --> 00:43:06,590
as well as with human
newborn infants.

1005
00:43:06,590 --> 00:43:10,970
And finally, I said infants
don't follow gaze to objects.

1006
00:43:10,970 --> 00:43:14,330
That's true, but it's also true
that if they see a person who's

1007
00:43:14,330 --> 00:43:16,370
looking directly
at them, and then

1008
00:43:16,370 --> 00:43:18,650
the person's gaze
shifts to the side,

1009
00:43:18,650 --> 00:43:20,870
they'll continue to
look at the person,

1010
00:43:20,870 --> 00:43:23,840
but their attention will
undergo a momentary shift

1011
00:43:23,840 --> 00:43:27,290
in the direction of the shift
of the other person's gaze.

1012
00:43:27,290 --> 00:43:27,860
OK?

1013
00:43:27,860 --> 00:43:30,080
So this has been shown
at two months of age

1014
00:43:30,080 --> 00:43:31,460
and also with newborn infants.

1015
00:43:31,460 --> 00:43:33,560
It's been shown with
photographs of real faces

1016
00:43:33,560 --> 00:43:35,840
and also with schematic faces.

1017
00:43:35,840 --> 00:43:38,204
The way to show that
attention is shifting

1018
00:43:38,204 --> 00:43:40,370
is to present infants with
an event that could never

1019
00:43:40,370 --> 00:43:41,780
happen in the real world.

1020
00:43:41,780 --> 00:43:44,450
You have an image of a face,
the eyes shift to the side,

1021
00:43:44,450 --> 00:43:47,240
either left or right, and
then the face disappears,

1022
00:43:47,240 --> 00:43:49,820
and a probe appears either
on the left or on the right.

1023
00:43:49,820 --> 00:43:51,890
They'll get to the
probe faster if it

1024
00:43:51,890 --> 00:43:54,980
appears on the side to which
the person shifted their gaze.

1025
00:43:54,980 --> 00:43:57,230
And nice control studies
show that it's not

1026
00:43:57,230 --> 00:44:00,770
just any kind of low level
motion in that direction that

1027
00:44:00,770 --> 00:44:02,390
gets them there.

1028
00:44:02,390 --> 00:44:05,210
So this could be a
sign of something

1029
00:44:05,210 --> 00:44:07,160
like infancy direct gaze.

1030
00:44:07,160 --> 00:44:10,100
And it engages something like
a state of engagement with

1031
00:44:10,100 --> 00:44:13,880
another person in which evidence
about the other person's state

1032
00:44:13,880 --> 00:44:18,110
of attention-- possibly also
emotion if the questionable

1033
00:44:18,110 --> 00:44:21,320
literature on empathy
emerging early is right--

1034
00:44:21,320 --> 00:44:24,770
this can be automatically
spread from one person

1035
00:44:24,770 --> 00:44:27,110
to a social partner.

1036
00:44:27,110 --> 00:44:29,510
So the hypothesis
is that infants

1037
00:44:29,510 --> 00:44:35,090
are finding other
potential social partners

1038
00:44:35,090 --> 00:44:38,780
from the beginning
of life, by looking

1039
00:44:38,780 --> 00:44:40,820
at things like gaze
direction, maybe also

1040
00:44:40,820 --> 00:44:43,610
infant-directed speech, as a
signal that someone else is

1041
00:44:43,610 --> 00:44:47,420
engaging with them, by
interpreting patterns

1042
00:44:47,420 --> 00:44:49,790
of imitation as a
communicative signal

1043
00:44:49,790 --> 00:44:51,890
that somebody is
tracking what they do,

1044
00:44:51,890 --> 00:44:56,990
and acting in kind with
them, and interpreting shifts

1045
00:44:56,990 --> 00:44:59,390
of attention as-- you're
responding to shifts

1046
00:44:59,390 --> 00:45:02,240
of attention by shifting
their own mental states

1047
00:45:02,240 --> 00:45:04,510
in the same direction.