A comparison of learned aversions to gustatory and exteroceptive cues in rats

Abstract

The experiment provides a direet eomparison of the ability of subjeets (rats) to assoeiate gustatory and exteroeeptive stimuli with illness. Previous experiments whieh have made similar eomparisons between gustatory and exteroeeptive eues have suffered from eertain methodological problems involving stimulus eontrol and eompounding. The present experiment utilized a between-subjeets design wherein half of the subjects had an auditory eue assoeiated with poisoning and half had a taste eue. In both eases, the other eue was present, but was not predictive of poisoning. The auditory cue, like the taste eue, oeeurred only du ring drinking. This eomparison was made in both an immediate and a delayed poisoning situation. The experiment found that while subjeets were able to quiekly assoeiate a taste eue with illness, they were unable to form a similar association between poisoning and the exteroeeptive stimulus. Results also showed that subjects will fail to aequire a taste aversion to a novel and salient gustatory eue when that eue is followed by illness only 50% of the time. This latter effeet was more pronouneed in the delayed poisoning situation.There has been recent discussion of biologically determined differences in the ability of an organism to learn associations between different classes of events. Seligman (1970), for example, has argued for a dimension of "preparedness" in the acquisition of associative connections. Seligman, as a major case in point, refers to a body of literature often called "taste aversion learning," wherein a nurnber of experiments have shown that subjects quickly learn an aversion to gustatory stimuli which are followed by illness, but do not learn a similar aversion to exteroceptive stimuli which accompany ingestion.These conclusions are based on two types of studies. In the first type, typified by Garcia and Koelling (1967), subjects were poisoned after drinking water with a distinctive taste or after drinking water in the presence of constant environmental cues. Subjects readily learned to avoid the taste, but not to avoid drinking in the presence of the exteroceptive stimuli. In a second type of study, typified by Garcia and Koelling (1966), subjects were made ill after drinking water in the presence of a compound stimulus composed of gustatory, auditory, and visual components. In testing the elements of the compound, subjects typically avoided the taste, but not the ingestion of water in the presence of the exteroceptive stimuli. These types of results have been found in experimental situations where the poisoning occurred immediately after ingestion, and also in situations where the poisoning was delayed as long as 45 min. Seligman (1970) and Requests for reprints should be sent to Thomas S. Hyde,

Taste aversion and the generality of the laws of learning.

“…The tendency of the taste of the food, rather than any other aspect, to become associated with illness is one of the best known characteristics of illness-induced learning. However, it should be remembered that despite occasional failures (Larsen & Hyde, 1977), it is possible for cues other than tastes to be associated with illness in rats, although often more trials and more careful training procedures are required (Riccio & Haroutunian, 1977;Rozin, 1969). P. J.…”

Role of exteroceptive background context in taste-aversion conditioning and extinction

“…Thus, in studies of exteroceptive control of aversions, attempts have been made to produce aversions to exteroceptive cues in the absence of a taste stimulus (e.g., Larsen & Hyde, 1977). It could be argued that the question of the role of exteroceptive stimuli in taste-aversion learning has not been addressed by the above studies.…”

Possible role of confounded taste stimuli in conditioned taste aversions

“…For example, it has long been known that exteroceptive cues, suchas brightness of wallsand floortexture, can be associatedwith illness (e.g., Garcia, Kimeldorf, & Hunt, 1957). However, exteroceptive cues are not alwayseasily associatedwith illnessand are not typicallyas effective as tastes (Best, Best,& Henggeler, 1977;Best, Best,& Mickley, 1973;Garcia, Kimeldorf, & Hunt, 1961;Garcia & Koelling, 1966;Garcia, Kovner, & Green, 1970;Green, Holmstrom, & Wollman, 1974;Hargrave & Bolles, 1971;Larsen & Hyde, 1977;Slotnik, Brown, & Gelhard, 1977). Oral stimuli suchas dry versus wet (Garcia, Hankins, Robinson, & Vogt, 1972) and warm versus cool (Nachman, 1970) have also been effectively associated with illness.…”