The acquisition of an appetite

Unlike older animals, weanling-age rats do not seek water to drink when the y are dehydrated despite the fact that a physiological sensitivity to dehyd ration is present very soon after birth. We demonstrate here that the appet itive behaviors needed to approach and obtain water become linked to dehydr ation only as a result of specific postnatal learning experience. Preventin g early experience with dehydration retards the developmental emergence of dehydration-induced, water-oriented behavior in young rats. But a single pa iring of water with dehydration can establish an appetitive response. These findings reveal a critical role of early learning in the development of go al-oriented behavior. Such a learning process is potentially characteristic of other behavioral systems, from the most basic appetites to complex moti ves.