Different psychophysiological responses induced by a stimulus change during the orienting task and the Concealed Information Test.

The orienting response (OR) account of the Concealed Information Test (CIT) posits that physiological responses to CIT items are components of the OR. Physiological variations within a stimulus sequence were investigated in an OR task (Study 1) and the CIT (Study 2). In Study 1, an unexpected increase in tone intensity was introduced after repeated standard tone presentations. The deviant tone elicited a large skin conductance response (SCR), heightened vascular tone, and self-reported surprise and also increased skin conductance level, self-reported arousal, and sustained vascular tone thereafter. In Study 2, the deviant relevant item presentation elicited a larger SCR and greater surprise compared with the frequent irrelevant item presentation, whereas vascular tone and self-reported arousal dropped after presentation of the relevant item. These results indicate that although phasic responses to a deviant stimulus were similar in both tasks, tonic variations following the stimulus change differed. Possible implications are discussed.