Assessment of depth perception in cats.

A behavioural method is described for the assessment of depth perception of kittens. Measurement is made of the smallest separation in depth that can be discriminated between two adjacent stimuli under both monocular and binocular viewing conditions. Normal animals can discriminate much smaller separations in depth when using two eyes than with monocular viewing, implying the presence of a cue to depth that is uniquely available with binocular viewing. The test provides a quick and reliable way of screening animals for stereopsis.