Have You Ever?

Have you ever walked across glass flooring at a great height? While the sight below might be breath-taking, many people would find it difficult to walk on the flooring. Even though you’re in no direct danger, it feels as heart-pumping as if you’re choosing to walk across the narrow edge of a cliff.

Here’s Why

Such fear of large heights has an obvious evolutionary benefit. This acrophobia has been observed in young children. However, through much of the twentieth century, details about this subject remained obscured.

Visual Cliff Experiment

The visual cliff study done by Eleanor Gibson and Richard Walk set out to fill in this research gap. They wanted to know if young infants were born with depth perception, could recognize the dangers of a large fall, and if they could ever be enticed to face such dangers.

The History

Eleanor Gibson and Richard Walk conducted their study in 1959 at Cornell University. They constructed a visual cliff by modifying a glass table and applying optical illusion techniques. To their thirty-six crawling infant participants (ranging from six to fourteen months old), it looked as if they were placed on the shallow side of the table and asked to cross to the deep side. They were asked to do so by their caregivers (typically parents) who would call out to them or hold an enticing toy to motivate the infants to move towards them. 

Nine infants never crossed the centerboard. Twenty-seven of the subjects crawled to the shallow side when enticed to do so. However, only three of those twenty-seven actually crawled off the visual cliff when they were called by their caregivers from the deep side. The remaining twenty-four children either crawled away from the visual cliff’s edge or cried out because they could not make it to their caregiver.

So What

People may claim this study proved that depth perception was innate, but that’s not true. This study only demonstrated that babies are able to perceive depth once they are able to crawl. This suggests that depth perception is something infants are born with, or something that develops rather quickly after their birth, but it does not definitively prove this. Later studies and experiments found that locomotive experience rather than age more accurately predicts infants’ wariness of heights. These findings suggest that while infants may be able to perceive depth, they don’t realize the consequences of falling until they gain experience moving around on their own.

While Eleanor Gibson and Richard Walk didn’t solve the mystery of depth perception or acrophobia, they certainly laid the groundwork for later scientists and researchers to make significant progress towards doing so. It’s important to remember that a study or experiment does not need to completely answer every query, or even the initial query that inspired it. Studies and experiments can often spawn new, more in-depth, well-researched questions that in turn lead to better defined and constructed studies and experiments. Not everything has to fall into place on your first try. The world is a complex place: some mysteries take hundreds of years to crack. The important thing is that we never give up trying to solve them.

    Learn More

    1. Campos, Joseph J., Bennett I. Bertental, and Rosanne Kermoian. “Early Experience and Emotional Development: The Emergence of Wariness of Heights.” Psychological Science, vol 3, number 1, January 1992, pp. 61-64.
    2. Möller, Eline L., Mirjana Majdandžić, and Susan M. Bögels. “Fathers’ versus mothers’ social referencing signals in relation to infant anxiety and avoidance: a visual cliff experiment. Developmental Science, vol 17, issue 6, Nov 2014, pp. 1012-1028. Doi: 10.1111/desc.12194.
    3. Richards, John E. and Nancy Rader. “Affective, Behavioral, and Avoidance Responses on the Visual Cliff: Effects of Crawling Onset Age, Crawling Experience, and Testing Age.” Psychophysiology, vol 20, issue 6, Nov 1983, pp. 633-642. Doi: 10.1111/j.1469-8986.1983.tb00930.x
    4. Richards, John E. and Nancy Rader. “Crawling-onset age predicts visual cliff avoidance in infants.” Journal of Experimental Psychology: Human Perception and Performance, vol 7, issue 2, 1981, pp. 382-387. Doi: 10.1037/0096-1523.7.2.382.
    5. Sorce, James F., Robert N. Emde, Joseph J Campos, Mary D. Klinnert. “Maternal emotional signaling: Its effect on the visual cliff behavior of 1-year-olds.” Developmental Psychology, vol 21, issue 1, 1985, pp. 195-200. Doi: 10.1037/0012-1649.21.1.195.

    Think Further

    1. What are some of the limitations of the original visual cliff experiment?
    2. What are some of the strong  points of the original visual cliff experiment?
    3. Why do you think depth perception is something even young infants have? What are its benefits? Drawbacks?

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