All of the animals in both A and P conditions were observed daily for the presence of certain visually controlled responses, known to be absent when dark-reared kittens are first brought into light.

One test determined whether an eye blink occurred when the experimenter's hand was brought swiftly toward the kitten's head; a behavior observed in normally reared animals.

A second test consisted of carrying the kitten obliquely downward toward a laboratory table at a slow rate.