ATTACK PRIMING AND AGGRESSIVE AROUSAL IN FEMALE SYRIAN GOLDEN-HAMSTERS, MESOCRICETUS-AURATUS

Earlier studies have found that priming a resident female hamster by a llowing it to attack a conspecific intruder transiently reduced the la tency of its attack on a second (probe) intruder. The present series o f experiments showed that the time the subject spent in contact with e ach intruder prior to attack revealed this priming effect more clearly than did the conventional total elapsed time measure. The inference t hat stimuli encountered during the first few minutes of intruder explo ration would heighten the subject's aggressive arousal was confirmed i n experiments showing that increasing exposure to an anaesthetized int ruder from 0 to 90 s systematically reduced subsequent attack latency. Ninety seconds of contact with an anaesthetized intruder just prior t o testing on a pair of priming and probe trials significantly reduced the priming effect. However, such exposure may not reproduce the full reduction in latency that follows an overt attack. Consecutive priming and probe attack latencies were uncorrelated even though the latter i s routinely shorter than the former. Attacks were therefore modelled a s stochastic events. Standard log survivor analysis suggested that att ack probabilities increase to an asymptote during both priming and pro be trials. A novel theta(t) transformation of the data showed more cle arly that the priming effect results from a probability of attack whic h starts at a higher level on probe trials and rises to asymptote fast er.