Taste aversion learning in horses.

The ability of ponies to learn to avoid a relatively novel food associated with illness was tested in three situations: when illness occurred immediately after consuming a feed; when illness occurred 30 min after consuming a feed; and when illness was contingent upon eating one of three feeds offered simultaneously. Apomorphine was used to produce illness. The feeds associated with illness were corn, alfalfa pellets, sweet feed and a complete pelleted feed. The ponies learned to avoid all the fees except the complete feed when apomorphine injection immediately followed consumption of the feed. However, the ponies did not learn to avoid a feed if apomorphine was delayed 30 min after feed consumption. They could learn to avoid alfalfa pellets, but not corn, when these feeds were presented with the familiar "safe foods," oats and soybean meal. Ponies apparently are able to learn a taste aversion, but there were constraints on this learning ability. Under the conditions of this study, they did not learn to avoid a food that made them sick long after consumption of the food, and they had more difficulty learning to avoid highly palatable feeds.

Alterations of male sexual behavior by learned aversions to hamster vaginal secretion.

Male hamsters poisoned after their first adult exposure to the vaginal secretion of female hamsters became hesitant to approach and ingest the secretion. The same aversion-training procedure also altered the responses of males to estrous females, changing the latency, frequency, and duration of a variety of behaviors that are commonly taken as indexes of sexual attraction or arousal and of copulatory performance. The effects suggest that the aversions to vaginal secretion alter the perceived meaning of the secretion for male hamsters, and analysis of the correlations between various measures of sexual arousal and performance support the hypothesis that separate mechanisms underlie the effects of the secretion on appetitive and consummatory sexual behavior.

Taste aversions to food flavors and vaginal secretion in golden hamsters.

Although rodents readily associate virtually any distinctive flavor with gastrointestinal illness when the flavor and illness have been paired, experience with a flavor can provide information that interferes with later attempts to produce aversions to the familiar taste. The vaginal secretion of female hamsters carries sexual information for males, which does not depend on previous experience, and that built-in information might also be expected to interfere with associations between the flavor of the secretion and illness. Surprisingly, male hamsters show dramatic changes in behavior toward the vaginal secretion when its presentation has been followed by lithium chloride poisoning, suggesting that mammalian responses to sex pheromones are far more easily modified by experience than has been supposed.

Taste aversions to sexual attractants.

The vaginal secretion of female hamsters serves as a sexual excitant or attractant for the male even in the absence of previous sexual experience, but attraction to the secretion can be altered with surprising ease by pairing ingestion of the secretion with gastrointestinal illness.