"Learned safety" as a mechanism in long-delay taste-aversion learning in rats.

Abstract

Notes that rats learn taste aversions with unusually long CS-UCS delays. The hypothesis was tested that the CS-UCS delay gradient is a learning curve: During the delay, a rat gradually learns that a taste is "safe." In 2 experiments with female white rats, a solution which an S drank only once became safe and resistant to learned aversions for at least 3 wks, suggesting a learned safety mechanism. If an S drank a solution twice (within the effective CS-UCS interval) before a single poisoning, it learned less aversion than if it received only the 2nd presentation. The learned-safety theory explains this result; a trace-decay or interference model cannot. (34 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)