A SCR investigation of the Perruchet effect

This study aimed to assess the relative contributions of associative learning and US sensitisation in an electrodermal variant of the Perruchet effect. In order to do this two counterpart experiments were run, ‘Per_Easy’ and ‘Per_Hard’. In the Perruchet effect a single stimulus (the conditioned stimulus, CS) is paired with a second stimulus (the unconditioned stimulus, US) on half the trials and on the other half the trials the US is not presented. Conditioned responding to the CS is typically found to dissociate from conscious expectancy for the US. In each experiment (Per_Easy and Per_Hard) there were two CSs, two different coloured squares, in Per_Easy these were easy to discriminate between and in Per_Hard extremely difficult to discriminate between. In both experiments one CS was always presented with the US and another was never presented with the US. The degree of similarity between the two CSs was varied in the two experiments to allow for assessment of associative learning and US sensitisation in these experiments.