UNCONDITIONED STIMULUS-INTENSITY AND RETENTION INTERVAL EFFECTS

In single-element taste-aversion learning, retention interval effects are seen if taste aversions are paradoxically weak when they are teste d 1 day after conditioning than when they are tested 3 or more days af ter conditioning. One explanation of this phenomenon is that weaker ta ste aversions may increase in strength across a retention interval. To test this possibility, rats were given saccharin followed by an uncon ditioned stimulus (US) of weak, medium, or high intensity; testing occ urred after a 1-day or a 5-day retention interval. The results showed retention-interval effects only at medium and high dosage levels, but not following a weak-intensity US. Furthermore, at the 5-day retention interval, aversion strength increased as the intensity of the US incr eased. However, at the 1-day retention interval, there were no signifi cant differences due to US intensity. In accordance with previous expe riments, this outcome suggests that nonassociative factors, such as US novelty, and not associative factors (e.g., US intensity), modulate t aste aversion performance on a 1-day test. Copyright (C) 1996 Elsevier Science Inc.