Visual cliff
The visual cliff is an apparatus created by psychologists Eleanor J. Gibson and Richard D. Walk at Cornell University to investigate depth perception in human and other animal species.
[1] Using a visual cliff apparatus, Gibson and Walk examined possible perceptual differences at crawling age between human infants born preterm and human infants born at term without documented visual or motor impairments.
[2] The visual cliff consisted of a sheet of Plexiglas that covers a cloth with a high-contrast checkerboard pattern.
To test this, they placed 36 infants, six to fourteen months of age, on the shallow side of the visual cliff apparatus.
Once the infant was placed on the opaque end of the platform, the caregiver (typically a parent) stood on the other side of the transparent plexiglas, calling out for them to come or holding an enticing stimulus such as a toy.
It was assumed if the child was reluctant to crawl to their caregiver, he or she was able to perceive depth, believing that the transparent space was an actual cliff.
[2] Another study measured the cardiac responses of human infants younger than crawling age on the visual cliff.
[7] James F Sorce et al. tested [8] to see how maternal emotional signaling affected the behaviors of one-year-olds on the visual cliff.
In contrast, when the visual cliff effect was absent, most of the babies crossed regardless of the mother's facial expressions.
After six days of being in the light, the kittens would avoid the deep side of the visual cliff (Rodkey, 2015).
When moving about in the dark, they respond to tactual cues from their stiff whiskers (vibrissae) located on the snout.
At four weeks, the earliest age that a kitten can skillfully move about, they preferred the shallow side of the cliff.
On the visual cliff one might expect an aquatic turtle to respond to the reflections from the glass as it might to water and prefer the deep side for this reason.
The large percentage that choose the deep side suggests either that this turtle has worse depth-discrimination than other animals, or that its natural habitat gives it less occasions to "fear" a fall.
Over this five-day experiment the heifers’ heart rates were measured along with the number of times they stopped throughout the milking facility.
