Transitions of physiological changes in the concealed information test

Abstract

The present study focused on temporal changes of physiological activities within trials during the concealed information test (CIT). Participants were assigned to two groups with an inter-stimulus interval (ISI) of 50 or 25 seconds in the CIT. A relevant item was a piece of jewelry that a participant stole in the preceding mock theft task. Measures were skin conductance level (SCL), skin conductance response (SCR), heart rate (HR), normalized pulse volume (NPV), and self-reported arousal and surprise. The results showed that physiological changes in response to irrelevant items tended to return to pre-stimulus levels within 25 seconds. Physiological recoveries were slower for SCL and HR but faster for NPV for the relevant item than for irrelevant items. Pre-stimulus physiological levels were maintained until the relevant item was presented and then declined, which was similar to the peak of tension effect. Results in the self-reported measures were in line with the physiological measures. Practical and theoretical implications were discussed.