Transcript Gibson And Walk (1960)

GIBSON AND WALK (1960)
The Visual Cliff
CONTEXT
Nativist view- innate ability to perceive the
world. Opposed to learning through experience.
 Lashley and Russell (1934)- rats reared in dark
could still jump correct distance to platform.


Criticism: Invalid- rats could have learnt to judge
distance through training.
AIM
Investigate whether depth perception is innate or
learned.
 Will mobile infants avoid a visual drop?

PROCEDURE: SAMPLE

36 human infants aged 6-14 months and their
mothers.

Must be mobile- able to crawl.
Followed by trials with animal young, e.g chicks,
kids, lambs, rats, puppies and kittens.
 Another trial used only kids (goats) and lambs
because they could be tested within 24 hrs of
birth.


No opportunity to learn to perceive depth.
PROCEDURE: EQUIPMENT

The Visual Cliff

Surface usually in a check pattern (to show clear
depth cues) and a drop covered by a glass floor.

The glass floor controls for other non-visual cues.
PROCEDURE- METHOD
Child is placed in centre of visual cliff.
 Mother beckons child towards her from both
sides (shallow and visual cliff) to test if the infant
is less inclined to cross a visual cliff.
 Animal trials were used to reduce the chance of
pre-crawl learning.

Animals were placed in the centre and the direction
in which they moved was tested (towards or away
from the visual cliff)
 Kids and lambs were then placed on a surface, which
could be lowered to create a visual cliff, to test their
response to visual cues suggesting the floor was
moving further away.

PROCEDURE- METHOD CONT.

In another condition the check
surface was replaced by a
uniformly grey one to ensure
the validity of the measure.

Was it the depth cues, which
are eliminated by the grey
surface, causing the
participant’s reactions?
RESULTS

27/32 infants moved off the centreboard.
All 27 crawled onto the shallow surface.
 Only 3 ventured on to the visual cliff.
 Many infants moved away from their mother if she
was beckoning them towards the visual cliff.

RESULTS CONT.

No lambs, kids or chicks ventured onto the visual
cliff.


In the adjustable cliff condition all animals froze
when the visual cliff dropped more that 12
inches.


When placed on the visual cliff they froze.
They did not adapt after multiple trials.
In the uniform grey condition animals showed no
preference for either side of the surface.
CONCLUSIONS
All animals, including humans, had intact depth
perception by the time they could move.
 In animals this occured within 24hrs of birth,
suggesting depth perception is innate.
 Thus, the nativist position is supported.
 The grey condition showed the innate mechanism
for depth perception involves interpreting
changes in patterns.

EVALUATION- STRENGTHS
The visual cliff is a safe and easily identifiable
measure.
 Visual cliff procedure controlled for extraneous
variables, such as touch perception. Improved
validity.
 Tested on a range of species.
 Straightforward procedure.

Easily replicable- good external reliability.
 Participants all had a very similar experience- good
internal validity.

EVALUATION- WEAKNESSES
Small sample.
 Large age range of infants. Infants have time to
learn depth perception.


Conclusions are justified by trials with other species.
Behavioural measure- could not test infant’s or
animal’s reasons for moving away from the visual
cliff. Issue of validity.
 Ethics- causing distress to infants and animals.
Cannot be asked for consent directly. Unable to
withdraw.

ALTERNATIVE EVIDENCE- SUPPORTING

Tondel and Candy (2007)
Method: Presented infants aged 5-7mnths with image
of fast-moving clown.
 Conclusion: Infants were able to track clown even at
speeds of 50cm/sec. Visual tracking is innate.


Sinai, Ooi, and Hi (1998)
Method: Adults ability to judge distance up to 7m.
 Conclusion: When the ground was even, texture was
used as a cue, and judgements of distance were more
accurate. When the pattern was obscured, e.g. By a
ditch, accuracy declined. Supports that pattern is an
important depth cue, as in Gibson and Walk’s grey
condition.

ALTERNATE EVIDENCE- OPPOSING

Pei, Pettet, and Norcia (2007)
Whilst some basic perceptual processes are innate,
they develop through experience.
 Carried out experiments using a range of patterns
and shapes, demonstrating that infants could not
recognise the more subtle differences in texture that
adults can.

PAST EXAM QUESTIONS
Section A
1. Summarise the aims and context of Gibson and
Walk’s (1960) research ‘The Visual Cliff’. [12]
2011
2.
Describe the findings and conclusions of Gibson
& Walk’s (1960) research ‘The visual cliff’. [12]
2009
Section B
1. With reference to alternative evidence, critically
assess Gibson & Walk’s (1960) research ‘The
Visual Cliff’. [12] 2009