Unformatted text preview: age of 27 days at first crawled or fell off the center board equally often on the deep and shallow sides.
Placed upon the glass over the deep side, they did not back in a circle like normal kittens but showed the
same behavior that they had exhibited on the shallow side. Other investigators have observed equivalent
behavior in dark-reared kittens; they bump into obstacles, lack normal eye movement and appear to "stare"
straight ahead. These difficulties pass after a few days in the light. We accordingly tested the kittens every
day. By the end of a week they were performing in every respect like normal kittens. They showed the same
unanimous preference for the shallow side. Placed upon the glass over the deep side, they balked and circled
backward to a visually secure surface. Repeated descents to the deep side, and placement upon the glass
during their "blind" period, had not taught them that the deep side was "safe." Instead they avoided it more
and more consistently. The initial blindness of dark-reared kittens makes them ideal subjects for studying the
maturation of depth perception. With further study it should be possible to determine which cues they
respond to first and what kinds of visual experience accelerate or retard the process of maturation.
From our first few years of work with the visual cliff we are ready to venture the rather broad conclusion that
a seeing animal will be able to discriminate depth when its locomotion is adequate, even when locomotion
begins at birth. But many experiments remain to be done, especially on the role of different cues and on the
effects of different kinds of early visual experience. References
1. Gibson, E. J., & Walk, R. D. (1960). The "visual cliff." Scientific American, 202, 67–
2. Fantz, R. L. (1961). The origin of form perception. Scientific American, 204(5), 66–72.
3. Turnbull, C. M. (1961). Some observations regarding the experiences and behavior of
the BaMbuti Pygmies. American Journal of Psychology, 74, 304–308.
4. Dement, W. (1960). The effect of dream deprivation.Sci ence, 131, 1705–1707.
5. Hobson, J. A., & McCarley, R. W. (1977). The brain as a dream state generator: An
activation-synthesis hypothesis of the dream process. American Journal of Psychiatry,
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This document was uploaded on 01/30/2014.
- Winter '14
- Developmental Psychology