Abstract
The present study investigated an essential difference between autonomic responses to critical and non-critical questions in the Concealed Information Test (CIT). The results of the first experiment, by using a mock crime, indicated that the only difference between responses to critical and non-critical questions lay in the volume of such responses. The latencies and change patterns of autonomic responses to critical and non-critical questions were identical. The results suggest that the difference in activation levels of the autonomic nervous system contributes to the difference between responses to critical and non-critical questions. Combining these results with physiological findings and principles, we proposed a model of the underlying mechanism and processes of autonomic responses in the CIT. This model can explain the direction of each physiological response, and the temporal order of the onset of these responses. Another experiment evaluated the validity of the model and indicated the suitability of the model for the autonomic responses in the CIT.
