Aversions to unflavored water and cup drinking produced by delayed sickness.

Rats drank from a cup and were then injected with lithium chloride. The result was an apparent association between the appearance of the cup and toxicosis. In Experiment 1, avoidance of drinking unflavored water from the cup was apparent after two trials in which toxicosis was induced either immediately or 1/2 hr. after such drinking. Consumption of sucrose solution from the cup prior to toxicosis, however, did not produce a statistically reliable aversion to drinking unflavored water from the cup. In Experiment 2, rats were repeatedly subjected to toxicosis 0.0, .5, 1.5, 4.5, or 18.0 hr. after drinking unflavored water from a cup. A reduction in drinking from the cup was inversely related to the delay of toxicosis, but only the 0.0- and .5-hr.-delay groups exhibited statistically reliable aversions. A later phase excluded the possibility that sensitization alone could account for the cup aversions. Marked aversions to the unflavored water itself were obtained in Experiment 1, but in Experiment 2 any such aversions were so weak that they could not have been responsible for the cup aversions.