Effect of a question theme on differential responding in the Concealed Information Test: Comparison of knowledgeable versus unknowledgeable contexts

The autonomic-based Concealed Information Test (CIT) focuses on differential responses to a crime-relevant item that is significant only for knowledgeable persons. This study examined whether pre-test instructions on question themes defining knowledgeable and unknowledgeable contexts modulate the magnitude of differential responses to the relevant item. The participants (36 men 46 women) were instructed to steal one item from one of two possible locations in a mock theft task. In the subsequent CIT, an identical set of items was presented under two different contextual conditions, and participants were asked what was stolen from each of the two locations. The location in which participants enacted the mock theft was defined as the “relevant, knowledgeable” context, whereas the other location where they did nothing was the “irrelevant, unknowledgeable” context. The context was specified by pre-test instructions, and the participants were asked what they had stolen in each context. During the CIT, skin conductance response, heart rate, and respiratory movement were recorded. The results indicated that differential responses to the stolen item occurred both in the relevant and the irrelevant conditions but tended to be smaller in magnitude in the latter. From an applied perspective, it was suggested that prior experience of similar crimes may lead to a false positive but the short study–test interval in this experiment should also be noted. Our finding implies that the context-specifying instructions in the CIT were a modulator rather than the sole determinant of the significance of the relevant item.