EFFECTS OF EXPOSURE TO A TO-BE-SHOCKED ENVIRONMENT UPON THE RATS FREEZING RESPONSE - EVIDENCE FOR FACILITATION, LATENT INHIBITION, AND PERCEPTUAL-LEARNING

Three experiments used the freezing response of rats to examine the ef fects of pre-exposure to an environment upon (1) its associability wit h shock and (2) its discriminability from a second environment. Experi ments 1 and 2 demonstrated that freezing was proportional to the inter val 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 (facilitatio n) and extended pre-exposures decreasing (latent inhibition) the impac t of a given T1-T2 interval on freezing. Experiment 3 provided evidenc e that the facilitatory and latent inhibitory effects resulting from b rief and extended exposures to the to-be-shocked environment were acco mpanied by an increase in discriminability. The results were taken to have supported the claim that pre-exposure changes associability as we ll as discriminability (Hall & Honey, 1989) and were discussed in term s of the model for perceptual learning proposed by McLaren, Kaye, and Mackintosh (1990).