Pre-extinction of sensory preconditioned electrodermal activity

In the present study, sensory preconditioning of human electrodermal activi ty was demonstrated. In the first phase of the experiment, two pairs of neu tral pictures of human faces were presented (A/B and C/D) sequentially. In the second phase, one picture of one pair was immediately followed by an el ectrocutaneous stimulus (B+), and one picture of the other pair was not (D- ). In the third phase the other picture of each pair (A and C) was tested. The effect of A and C alone presentations (pre-extinction) between the firs t and the second phase was investigated. When only those participants that showed reliable B+/D- differentiation were considered, the extinction group did not show stronger conditioned electrodermal activity to A than to C, w hereas the control group did. These findings suggest that sensory precondit ioning of anticipatory/preparatory responding only occurs when the pre-cond itioned stimulus (A) actually predicts the conditioned stimulus (B).