Experiment Code:
Per_RT_noCS

Introduction & Research Question:
This study aimed to determine whether the conditioned stimulus (CS) in the reaction time (RT) version of the Perruchet effect is instrumental to the production of said effect. 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 this experiment there were two USs, one requiring participants to make a speeded left RT response and another a speeded right RT response (no expectancy ratings were recorded). Importantly, there was also no CS in this experiment. If the CS is important in the production of the Perruchet effect then removal of the CS in this experiment should distort RT responses, whereas if the CS is not important then a similar RT pattern should be produced to that seen in previous Perruchet experiments. 

Participants:
32

Experiment Software:
Matlab

Method:
Participants responded to two USs (the words ‘peanut butter’ or ‘brown sugar’), with one of two speeded key presses, left Ctrl or left Alt (it was counterbalanced across participants which of these two keys were required for presentation of each US). The US remained on screen until a key press was made, and if an incorrect response was made auditory feedback was given. Trials were presented in a sequence conforming to a randomisation with restriction method used in all Perruchet effect protocols. The inter-trial interval varied between 2 and 5 seconds. There were two experimental blocks in between which the participants were given a short comfort break. 

Experimenter:
Amy McAndrew

Location:
230-1, 230-2 
Washington Singer Laboratories, University of Exeter

Date:
October-December 2013

Data file names:
Per_RT_noCS_Px (Contains each RT response for each trial, as well as the sequence of trials).