Reexamination of contextual conditioning with massed versus distributed unconditioned stimuli.
Sprague-Dawley rats were placed in the black compartment of a 2 compartment choice apparatus and received a series of unsignaled footshocks at fixed intertrial intervals (ITIs), with ITI duration varied across groups. Contextual conditioning was assessed using place preference and freezing tests. In Experiments 1 and 3, time spent in the unshocked, white compartment in a preference test decreased monotonically with increasing ITI. In Experiment 2, less freezing occurred in the 3-s than in the 60-s groups. An inverted U-shaped relationship between ITI and freezing emerged when a full range of ITIs was used in Experiment 3. The results have implications for the learning-performance distinction and suggest that short ITIs may promote contextual conditioning.
Williams
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Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
Frame
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LoLordo
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D000818:Animals; D001245:Association Learning; D002755:Choice Behavior; D003214:Conditioning, Classical; D005239:Fear; D005795:Generalization, Stimulus; D008297:Male; D011939:Mental Recall; D009043:Motor Activity; D051381:Rats; D011919:Rats, Inbred Strains; D012931:Social Environment