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Gibson, E. J., & Walk, R. D. (1960). The” visual cliff”.Scientific American, 202(4), 64-71.
Aim
Eleanor J. Gibson and Richard D. Walk (1960) investigated the ability of newborn animals and human infants to detect depth.
Gibson and Walk tested whether youngsters would crawl over an apparent cliff – if the neonates did it could be assumed that the ability to see depth was not inborn.
If they did not, this would support a nativist view – thatperceptual abilitiesare innate.
Procedure
Their apparatus consisted of a “bridge” on either side which was a sturdy glass platform. One side of this had a chequered pattern immediately under the glass (the “shallow side”). On the other side of the bridge was a “cliff” – the chequered pattern was beneath a vertical drop.
Experiment 1
Sample: 36 infants ranging in age from six months to 14 months. Their mother also participated in the experiment.
The dependent variable (DV) was whether or not the child would crawl to its mother.
This was arepeated measures designbecause the infant was called from both the cliff side and the shallow side of the apparatus.
Experiment 2
Using the same apparatus, Gibson and Walk tested chicks, lambs, and kids (young goats), all less than 24 hours old.
The studies using other species are quasi (laboratory) experiments. The naturally occurring independent variable (IV) was the animal species, e.g., rat/chick/lamb/kitten.
The dependent variable (DV) was whether the animal preferred the shallow side or the deep side of the visual cliff apparatus.
They also used an adjustable floor on the deep side of the cliff so that the test could start with it in the high (and therefore safe) position but could be suddenly lowered once the animal was on it. This gave them the opportunity to observe the animal’s response and to see whether it learned from the experience of not “falling downwards.”
Other species were also tested, including rats (which were additionally tested with a raised bridge) and kittens, which were several weeks old before they could be tested. Some kittens were tested after being reared in the dark.
Findings
Conclusion
As the infants were able to detect the danger from the “cliff” side, Gibson and Walk concluded that their depth perception might be innate – it was at least present as soon as they could crawl.
However, as human infants take several months to crawl, it is possible that they had learned their ability to perceive depth during this time. The second experiment aimed to explore this possibility using animals.
Animals are able to judge depth as soon as they are mobile, whether that is immediately after birth/hatching or somewhat later. Although this is dependent on visual experience (i.e., being kept in the light), the time taken to recover from this deprivation is very short compared to the length of deprivation.
Together, the findings suggest that depth perception is an innate process.
Critical Evaluation
The procedure was a rigorously controlled laboratory test, so it offered a reliable – but also safe – measure of depth perception. As it was possible to eliminate or control the influences of other senses (such as touch from the rats” whiskers), they ensured it was a valid test of visual perception.
The consistency of the results over a range of species, including humans, adds credibility to the findings. However, the sample of human infants was quite small, and the age range rather large – some were likely to have been crawling for some time before they were tested.
The investigation of thenature-nurture issuein perception didn’t end with Gibson and Walk’s research. This only explored theplasticityof infant perception, so the question of whether adult perception could adapt was not considered.
In these situations, the world at first seems upside down or muddled, but over time the brain adapts to the change, and normal perception returns.
In such situations, people adapt readily – within about an hour – but only if they are able to actively interact with their environment. Participants who are pushed around in wheelchairs fail to learn to cope with the visual distortion (held 7 Bossom, 1961). Findings such as these tell us that, at least in some respects, depth perception is learned.
References
Gibson, E. J., & Walk, R. D. (1960).The “visual cliff.”Scientific American, 202(4), 64-71.
Kohler, I. (1962).Experiments with goggles.Scientific American, 206(5), 62-73.
Stratton, G. M. (1897).Vision without inversion of the retinal image.Psychological Review, 4(4), 341.
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
Julia RusselHead of PsychologyBSc (Hons), PsychologyJulia Russell has over 25 years experience as a Psychology teacher. She is currently Head of Psychology at The Queen’s School, Chester. She is Principal Examiner for two major awarding bodies, visiting tutor at Wrexham Glyndŵr University and an established author.
Julia RusselHead of PsychologyBSc (Hons), Psychology
Julia Russel
Head of Psychology
BSc (Hons), Psychology
Julia Russell has over 25 years experience as a Psychology teacher. She is currently Head of Psychology at The Queen’s School, Chester. She is Principal Examiner for two major awarding bodies, visiting tutor at Wrexham Glyndŵr University and an established author.
