Primacy effects induced by temporal or physical context shifts are attenuated by a preshift test trial.
When subjects are sequentially trained with a cue (A) paired separately with two outcomes (B and C) in different phases (i.e., A-B pairings followed by A-C pairings) testing in the training context after short retention intervals often reveals recency effects (i.e., stronger influence by A-C). In contrast, testing after long retention intervals or testing in a context different from that of training sometimes reveals primacy effects (A-B). Three experiments were conducted using rats in a Pavlovian conditioned bar-press suppression preparation to ascertain whether a nonreinforced test trial in the training context soon after training can attenuate this shift to primacy. Experiment 1 demonstrated that exposure to A shortly after both phases of training, but prior to a long retention interval, can attenuate shifts from recency to primacy otherwise observed with a long retention interval. Experiment 2 showed that exposure to A in the training context can also eliminate the shift from recency to primacy otherwise produced by shifting the physical context between training and test. Experiment 3 discredited a potential account of the results of Experiments 1 and 2. The effects observed in Experiment 1 and 2 are interpreted as early testing in the training context serving to initiate rehearsal of the A-C association due to the temporal proximity of A-C training.
Wheeler
Daniel S
DS
State University of New York at Binghamton, Binghamton, NY 13902-6000, USA.
Miller
Ralph R
RR
D000818:Animals; D001522:Behavior, Animal; D003071:Cognition; D003214:Conditioning, Classical; D003216:Conditioning, Operant; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012153:Retention, Psychology; D013997:Time Factors