Asymmetry in facial expression.

paired with LiCI can be anticipated and avoided-that the anticipation of a taste, rather than the taste itself, can be aversive. The usual taste-aversion experiment demonstrates only escape from an aversive taste. As a historical sidelight, this is a particularly clear demonstration in the rat of what Tolman called an "insight" or "foresight" mechanism (a sign-gestalt-expectation). More than 40 years ago, Miller showed that such a mechanism could be deduced from Pavlovian conditioning principles in the form of Hull's fractional anticipatory goal response (13). Experiment 2 adds the finding that PRF training can reduce (immunize the rat against) the suppressive effects of the anticipation of the conditioned aversive taste and that such training attenuates the suppression of drinking of such a taste solution. If rats are reinforced intermittently and inconsistently with a particular flavored solution, they will avoid that flavor less and drink more of it when it is subsequently paired with gastrointestinal illness. Such a finding has potential practical as well as theoretical implications. One practical application might be to therapeutic situations in which taste aversions and anorexia frequently result from drug or radiation treatments or chemotherapy (14). The theoretical implications are for broadening the range of generalization and transfer of persistence in responding across motivational-reward systems (15). JAW-SY CHEN* ABRAM AMSELt Department ofPsychology, University of Texas, Austin 78712