Young kittens can learn complex visual pattern discriminations.

Kittens begin to display visually elicited responses shortly after eye opening. The pupillary reflex, optokinetic response, visual placing and avoidance of the deep side of the visual cliff all appear between the second and fifth weeks of life, and evidence of visual learning in homing behaviour has been described at the same early age. However, an attempt to elicit pattern preferences in kittens of this age (usually considered the easiest way to demonstrate discriminatory behaviour in immature organisms) was unsuccessful, evidently because such kittens show little spontaneous visual interest. This is surprising in view of electrophysiological findings which emphasise the importance of the fourth to sixth weeks in the development of cortical feature-analysing mechanisms; perhaps the stimulus-seeking methodology of Dodwell et al. is anappropriate for the visual modality at such an early age. Recently, visual acuity measurements have been reported for kittens as young as 30 d of age using a contour versus no-contour discrimination on a modified Lashley jumping stand. With this technique we have now trained kittens of under 50 d of age to perform more complex pattern discriminations.