馃攳
Babies on the Brink - YouTube
Channel: SciFri
[10]
everyone has had some kind of an
[12]
experience feeling something kind of
[15]
like fear of heights and it makes
[16]
perfect common sense that we shouldn't
[18]
jump over the edge of a drop-off because
[20]
it's dangerous and if it's dangerous
[22]
then we should probably be afraid of it
[25]
probably exactly how and when this
[28]
hypothetical fear develops makes for
[31]
pretty gleeful research inside dr. Karen
[34]
Adolf's lab we're discovering some
[36]
surprising things that are flying in the
[38]
face of you know how people have studied
[40]
locomotion for the last hundred years
[42]
including what babies do and feel when
[45]
they're on a Ledge so the story about
[49]
fear of heights is that there was a very
[52]
very famous classical study in
[54]
developmental psychology by Gibson and
[56]
walk in 1960 that showed that human
[59]
infants an instance of a number of
[61]
different species will avoid crossing
[64]
over an apparent drop-off on what they
[66]
called a visual cliff as soon as the
[68]
baby to move about it can be observed in
[70]
the same way other animals it's a glass
[74]
table and on one side there's a
[77]
checkerboard pattern surface right under
[79]
the glass the other side of the table
[81]
the patterned surface is way down on the
[84]
floor so visually it looks like a big
[87]
three-foot drop-off so when human babies
[90]
first begin crawling most of them will
[92]
crawl over the apparent drop-off but
[94]
after several weeks of curling
[95]
experience then they'll begin to refuse
[98]
to crawl over the drop-off and the
[100]
conventional interpretation of this was
[102]
that infants are avoiding the drop-off
[105]
because they're afraid of heights
[106]
backing away vertically she's not
[109]
interested she wants no part of that
[110]
side the experiment became the shaky
[113]
foundation for the myth that crawling
[115]
and Nate Lee teaches us to fear Heights
[117]
maybe it's avoid going over the drop-off
[119]
because they're afraid of heights how do
[121]
we know they're afraid of heights
[122]
because they avoided curling over the
[124]
drop-off so as you may have noticed the
[126]
argument is circular as it happened the
[129]
visual cliff was a better test of an
[131]
infant's depth perception not their fear
[133]
of heights and if you look closely you
[135]
may have actually noticed that the
[137]
babies don't look particularly scared
[139]
perfectly safe surface of support so
[142]
after one trial human infants cleverly
[144]
figure this out and then they will crawl
[146]
over the drop-off so how do you really
[149]
test if a baby's scared of heights you
[151]
can test babies at the edge of a real
[152]
cliff where there's no safety glass it's
[155]
just an actual drop off and the drop off
[157]
can be adjustable so it can be little or
[159]
really really big and why stop there
[162]
inside dr. Adolf's infant action lab
[164]
babies are tested on a variety of
[166]
apparatuses in tests Maeby's at the edge
[168]
of the slope so it can be super super
[170]
super crossing bridges that are white or
[173]
narrow over a surface of support and so
[175]
on if there's no safety glass you can
[177]
test the same baby dozens on dozens and
[180]
dozens of trials in the same session and
[182]
that means that you can determine for
[184]
each individual infant when they think
[187]
that that surface is safe and when they
[189]
think it's risky within a couple of
[191]
degrees of accuracy like two degrees of
[193]
accuracy for a slope doctor Yadav has
[195]
spent 25 years running tests like these
[197]
and the resulting datasets are both
[200]
convincing and adorable infant spend
[202]
most of each trial right at the edge of
[205]
the precipice they're reaching their arm
[208]
down over the drop-off they are putting
[210]
their little feet or their little hands
[212]
on the bridge and taking little tiny
[214]
steps at the edge and all the way all
[216]
they're doing it with either neutral or
[218]
positive facial expressions what's more
[221]
surprising is how their approach changes
[223]
as they learn different forms of
[225]
locomotion so what happens is that when
[227]
babies first begin crawling they'll
[228]
crawl right over the edge that over
[230]
weeks of crawling their responses get
[232]
more and more accurate until finally
[234]
they're an adult like levels so that
[236]
they can tell precisely whether a slope
[238]
is safe for pulling or whether a
[240]
drop-off is safe for crawling but then
[242]
the next week when these babies stand up
[244]
and face these same drop-off scene slope
[246]
team apparatus now at the new Walker
[249]
they walk right over the edge so in fact
[252]
there seems to be four learning curves
[254]
and development as babies learn to sit
[256]
there to crawl as they learn to cruise
[258]
and then fine
[259]
as they learn to walk so if they were
[261]
afraid of heights you should just be
[263]
afraid of heights in the rain and on a
[265]
train and in a tree you shouldn't see
[267]
four separate learning curves so if
[270]
babies aren't learning to be afraid of
[271]
heights what are they learning I think
[274]
that what babies are learning over weeks
[276]
of sitting crawling cruising walking as
[277]
they're learning to perceive the
[279]
relations between their bodies and the
[281]
environment they're discovering what's
[283]
possible and what's just a little too
[286]
far and you can learn that without
[289]
feeling any sort of fear at all in fact
[291]
owner Gibson the person who first
[293]
invented the visual cliff robe later in
[296]
her life as a goat is peering over the
[298]
edge of a steep crack it knows not to
[300]
walk off the edge and she said I don't
[302]
think of feeling any emotions at all it
[303]
just knows not to go and that's what
[305]
we're seeing a baby who probably know
[307]
not to go probably for science friday
[313]
and Luke grasp
Most Recent Videos:
You can go back to the homepage right here: Homepage