Enhanced unblocking from sustained post-trial surprise.
Haselgrove M., Tam SK., Jones PM.
Two appetitive conditioning experiments with rats investigated the mechanisms and properties of unblocking that results from the surprising omission of an expected post-trial unconditioned stimulus (US). Experiment 1 demonstrated unblocking under circumstances in which differences in the contribution of generalization decrement and within-compound associations are equated across experimental and control groups. Following Stage 1 training in which a conditioned stimulus (CS) A was followed by a US and a post-trial US, in Experiment 2 we arranged for the post-trial US to be present on some trials with AX but not others. Under these circumstances an enhancement of unblocking to X was observed, relative to a group who received standard unblocking by US omission. The implications of these results for attentional and US-processing theories of associative learning are discussed.