




The ability to comprehend that some
objects are further away than others
Binocular cues (pen test)
Relative size
Texture gradient
Motion Parallax

How could we apply this to vision?

Nature, nurture, both

Nativists, empiricists, interactionists

What is the nervous system?

The brain and spinal cord make up the central
nervous system. The peripheral nervous system
are the nerves that lead from the spinal cord to
the rest of the body. Both the CNS and PNS make
up the nervous system.


We are born with a complete nervous system,
but it is not mature.
Use the following words to complete the gaps in
the paragraph

Nativists, empiricists, interactionists

Evolution
Adaptation to environment. Traits are adaptive
if they lead to increased survival and
reproduction
 Human infants have limited mobility
 Many animals are precocial: relatively mature
and mobile from birth.


If depth perception is innate, it would be
apparent by the time a young animal is
mobile.

Adaptive: A young animal which does not have
this ability at this critical time is less likely to
survive, and therefore an innate ability to
perceive depth would be adaptive.


Lashley and Russell (1934) reared rats in
darkness and found they could still jump the
correct distance onto a platform. They
suggested this shows depth perception is
innate.
How else could you explain this finding?


RIGHT!
Gibson and Walk thought the rats could
have learned about depth in the course
of the training and dismissed Lashley’s
conclusion.

To investigate if depth perception
is learned through experience or
whether it is present from birth


If depth perception is innate, then it
should be apparent by the time
infants are able to move
independently.
Humans are not mobile until about
6 months old: inconclusive results.

A child who could perceive depth at
6 months may have always been
able to do so (nativist), or may have
learned to do so in the 6 months
since birth (empiricist)

Therefore they decided to also test the depth
perception of a range of non-human animals.


Kids (baby goats), lambs, rats, turtles, chicks, and
kittens.
As some of these animals can walk from birth.
This would then provide more evidence about
whether depth perception is innate.


How many infants were used?
What were the other variations? (pg 111)

How many infants moved? (pg 112)

How many chicks, kids and lambs move?

Rats, kittens, turtles...?

Humans:
Most human infants can discriminate depth as
soon as they can crawl. However, some of them
backed of onto the deep side of the cliff,
meaning that they should still not be left close
to a cliff edge
 Nature or Nurture?


Generally, the findings from non-human
animals fits with the life history and natural
environment of the animal.

How does this apply to each species?


It supports a nativist position as all of the
evidence suggests that depth perception is
adaptive. The animals have depth perception
which is suitable for their environment and
motor ability.
All animals were able to perceive depth by
the time they could walk, implying that it is
innate. If it was learned, the animals may not
have been able to properly judge depth.




Dark reared kittens: visual input needed for
maturation
Depth perception isadaptive
__________
Motion parallax is innate, relative size may
need to be learned.
Main conclusion: Quote from Gibson

Usual Headings
Methodology
 Validity
 Sampling
 Ethics


Bullet point as many evaluation points as
you can think of.


Gibson and Walk’s study could only use
infants that could move
Schwartz et al (1973)
Infants placed directly onto deep side. Heart rate
measured
 5 months: no change in heart rate
 9 months: heart rate increased.



What does this imply?
Alternative explanation?

Bower (1970)
Infants shown two discs of different sizes. The
baby was approached by both, but feared the
one which was closer.
 Therefore, Infants as young as 6 days have
depth perception


Sorce (1985)
Performed a variation on the visual cliff.
 Watch the video, and record what he did and
found.


Witherington et al (2005)
Infants who were experienced at crawling but
not walking showed less fear of the visual cliff
than those who had started walking
 New learning has to take place when the world
is viewed from a new perspective



Find one more piece of research that you
find interesting on pg 115. Summarise
findings and conclusions
Use three colours to highlight research that
supports, contradicts, or develops Gibson
and Walk’s research.