Effects of exposure to a to-be-shocked environment upon the rat's freezing response: evidence for facilitation, latent inhibition, and perceptual learning.
Three experiments used the freezing response of rats to examine the effects of pre-exposure to an environment upon (1) its associability with shock and (2) its discriminability from a second environment. Experiments 1 and 2 demonstrated that freezing was proportional to the interval between exposure to the environment at time T1 and the occurrence of shock at T2. This function was shifted by pre-exposure to the to-be-shocked environment, with brief pre-exposures increasing (facilitation) and extended pre-exposures decreasing (latent inhibition) the impact of a given T1-T2 interval on freezing. Experiment 3 provided evidence that the facilitatory and latent inhibitory effects resulting from brief and extended exposures to the to-be-shocked environment were accompanied by an increase in discriminability. The results were taken to have supported the claim that pre-exposure changes associability as well as discriminability (Hall & Honey, 1989) and were discussed in terms of the model for perceptual learning proposed by McLaren, Kaye, and Mackintosh (1990).
Kiernan
M J
MJ
University of New South Wales, Kensington, New South Wales, Australia.
Westbrook
R F
RF
D000818:Animals; D001245:Association Learning; D001522:Behavior, Animal; D003214:Conditioning, Classical; D003463:Cues; D004193:Discrimination Learning; D004597:Electroshock; D007103:Immobilization; D007266:Inhibition, Psychological; D008297:Male; D051381:Rats; D017208:Rats, Wistar