Operant conditioning of the visual smooth pursuit in young infants.

Smooth pursuit is a complex behaviour which is not considered as totally functional at birth. The lack of maturation of the visuo-motor systems is generally invoked to explain this phenomenon. However, if this oculomotor response is an operant behaviour, an alternate explanation may be found in the absence of previous confrontation with the environmental contingencies. A first group of young infants were placed in situations in which their oculomotor responses could produce an auditory stimulus. In such situations, young infants are able to improve their pursuit. Music was randomly delivered to a second group. No music was delivered to a third group. For the last two groups no augmentation of the proportion of slow movements was observed. Our main conclusion is that visual tracking has the properties of an operant behaviour and may be enhanced at birth. These results will be discussed within the frameworks of the behavioural discrepancy and of the maturationist hypotheses of the ocular motor control.