Conditioned social aversion in the male Mongolian gerbil (Meriones unguiculatus).

Adult male Mongolian gerbils formed conditioned social aversions to young male conspecifics. The basic paradigm consisted of pairing a subject with a young animal (test stimulus) for 5 min and then injecting the subject with lithium chloride to produce gastrointestinal distress. When retested 48 hr later, the subject avoided the animal used as a test stimulus, as indicated by significantly decreased investigation time and approach frequency. Through a series of experiments on dose level, delay of toxin injection, and stimulus generalization, it was demonstrated that a dose of .03 ml/g body weight of .15 M LiCl is effective, the injection of the toxin should be given within 15 min of the preliminary social pairing, the social aversion formed is specific to the particular first paired stimulus animal, and isolation between test sessions is necessary for an aversion to develop. This paradigm of conditioned social aversion extends our knowledge of the learned aversion process and demonstrates that this type of learning can be generalized to a social situation by gerbils.