The aim of the study was to test whether self produced movements related to changes in stimulation are essential for the development of certain perceptions.
Ten pairs of kittens were used, and each pair came from a different litter. In each pair, there was one active, and one passive. Kittens are higher mammals, to which humans also belong.
The method is a Laboratory experiment with a yoked control design, meaning that the rate of responding is compared to that by a control subject.
Each pair of kittens was attached to a 'roundabout' which was propelled by the movements of kitten A. Kitten A could move up, down, toward or away from the center, and rotated clockwise or counterclockwise. Kitten B was also attached to the roundabout, but was carried in a basket so it could not control its own movements. It moved exactly the way kitten A moved. The apparatus was housed in a cylinder with black, white and metal colored vertical strips on the walls inside. The center of the roundabout, which was also striped, prevented the kittens from seeing each other.
None of the kittens received light before the experiment, as they were all reared in darkness from birth. The point of this experiment is that both kittens were made to learn to see the world receiving the same visual stimulation. The difference was that one moved actively, while the other moved passively. The pairs spent three hours per day in the apparatus for six weeks. When not in the apparatus, all kittens were housed in darkness with their mother and littermates.
Visually guided paw placement: the kitten was held by the experimenter with its head and forelegs free and was carried down to the edge of the table. A kitten with normal visual experience extends its paws ready to make contact with the surface. Avoidance of a visual cliff: the kitten is placed on the central 'bridge' from which it can stay still or walk onto either the 'shallow' or 'deep' side. A kitten with normal visual experience experience avoids the 'deep' side. Bump to an approaching object: the kitten was held still on a standing position and the experimenter brought his hand quickly towards the kitten's face (stopping just in front of it). A kitten with normal visual experience blinks in response. Visual pursuit of a moving object: the kitten was show the experimenter's hand moving slowly in front of it. The movement of the kitten's eyes was recorded. A kitten with normal visual experience follows the movement with it's eyes. Pupillary reflex to light: a flashlight beam was moved across the eye and the change in pupil size was noted. The pupil of a kitten with normal visual experience shrinks in response. Tactual placing response: the kitten was held as in the paw placement test, but its front paws were put against the vertical surface of the table. A kitten with normal visual experience response by moving its paws to the horizontal surface.