Enhancement of food aversion by exposure to a poisoned conspecific in Norway rats (Rattus norvegicus)

Abstract

Two experiments were conducted to determine whether exposure to a poisoned conspecific enhances prior food aversion in rats. In Experiment 1, subjects were serially exposed to two foods, cocoa-flavored and cinnamon-flavored ones, and were then poisoned 1 h later. On the next day, they were exposed to a poisoned conspecific that had eaten a cocoa-flavored food. On the subsequent choice test, subjects had an enhanced aversion to cocoa-flavored food. The result was replicated in Experiment 2, in which a cinnamon-flavored food was assigned as a target. The results are discussed in relation to previous findings.

Insights from social transmission of information in rodents

“…Effectively, Galef and Whiskin found, across a number of experiments, that rats fail to show increased reliance on socially acquired information while foraging in risky situations (common sense would suggest those to be circumstances under which social reliance should be favored); yet, multiple studies have shown that rats readily prefer food that healthy demonstrator conspecifics have eaten. Still, and perhaps counter‐intuitively, multiple studies have also shown that rats do not seem to avoid ingesting food that sick or even unconscious rats have eaten (although see also References ). In fact, their preference for the food eaten by an ill demonstrator appears to be just as strong as their preference for food demonstrated by a healthy rat .…”

The effect of prior acquisition of food aversion on the poisoned‐partner effect

“…In the present study, the conditioning was weakened by delayed presentation of the US (LiCl) in order to decrease any potential floor effects. The rats in this study, which were injected with LiCl 1 h after the consumption of cocoa-flavored pellets, consumed it significantly more than ones immediately injected with LiCl (Nachman, 1970;Hishimura, 1998Hishimura, , 2000. Thus the food aversion should have been rapidly extinguished in group CN.…”

“…Recently, we found that rats that had been taught aversion to an unfamiliar food had increased aversion when they were subsequently exposed to a poisoned conspecific that had eaten the same food (Hishimura, 1998; see also Hishimura, 2000). Thus, if rats' responses to a poisoned conspecific were enhanced by their previous aversive experience, the subjects that had experienced food aversion should show a stronger aversion to the food that they had eaten immediately before exposure to a poisoned conspecific that had not eaten any food.…”