Expression of a taste aversion conditioned with an odor-taste compound: Overshadowing is relatively weak in weanlings and decreases over a retention interval in adults

Abstract

Adult rats were injected with lithium chloride (LiCl) after consumption of a novel flavor (chocolate milk) that either was or was not presented together with a novel ambient odor (banana) as a compound conditioned stimulus (CS). In Experiment 1, the adults' consumption of the flavor 24 h after conditioning was compared with that of weanling rats given the same conditioning treatment on Postnatal Day 21. The results confirmed previous indications that the reduction in aversion observed for adults conditioned with the compound CS (overshadowing) was weak or nonexistent in weanlings. After a longer retention interval (21 days), there was no evidence of overshadowing in adults despite maintained retention of the basic conditioned aversion. In Experiment 2 this decrease in overshadowing after a long retention interval was replicated with adult animals and extended to a different method of testing. The form of the effect was the same as in Experiment 1: The decrease in overshadowing occurred over the retention interval without loss in retention of the basic taste aversion; the decrease in overshadowing was a consequence of an increase in the flavor aversion displayed by animals conditioned with the compound CS.The impaired flavor aversion (i.e., the overshadowing) observed shortly after conditioning apparently was due to factors associated with memory retrieval, rather than to reduced attentional or associative strength.Recent studies have shown that the learning of multipleevent episodes is more complex than was once thought.

A response rule for positive and negative stimulus interaction in associative learning and performance

“…The SOCR model (as the extended comparator hypothesis, which serves as its basis) has trouble to explain changes in responding to a CS as function of passage of time. Specifically, the SOCR model fails to explain relevant findings in the stimulus competition literature, such as spontaneous recovery of responding after overshadowing (Kraemer, Lariviere, & Spear, 1988) or blocking (Pineño, Urushihara, & Miller, 2005). The problem of the SOCR model is, not only that there is no mechanism by which passage of time could affect responding to a CS, but also that there is no obvious reason why the mechanisms already existing in the model should be affected by passage of time.…”

Spontaneous Recovery From Forward and Backward Blocking.

“…This phenomenon, like the recovery achieved by reminder treatments, supports a performance-deficit view of cue competition while posing a problem to acquisition-deficit models because the blocked CS is assumed to not increase its associative strength without further training trials. Although spontaneous recovery of responding has been demonstrated after overshadowing (Kraemer, Lariviere, & Spear, 1988) and the relative stimulus validity effect (Cole, Gunther, & Miller, 1997), the study of spontaneous recovery following blocking has received little attention in the literature. Spontaneous recovery from the US-preexposure effect, which is often viewed as forward blocking by the context, was demonstrated by Batsell (1997) and J. S. Miller, Jagielo, and Spear (1993) using conditioned taste aversion preparations.…”

One bottle too many? Method of testing determines the detection of overshadowing and retention of taste aversions

“…Furthermore, recent work in the study of compound conditioning has focused on differences in aversion strength at various retention intervals (Batsell & Best, 1992a, 1992bKraemer, Lariviere, & Spear, 1988;Miller, Jagielo, & Spear, 1990). For example, Batsell and Best (l992b) demonstrated that both single-taste and overshadowed-taste aversions were significantly weaker at a short retention interval (i.e., 1 day) than at a longer one (i.e., 21 days).…”