Selective attention, not cognitive load, elicited fewer eyeblinks in a concealed information test.

The concealed information test (CIT), a memory detection test, compares physiological responses to crime-related and crime-unrelated items. This study elucidated processes involving spontaneous eyeblinks during the CIT by manipulating participants' intention to conceal. Thirty-four participants committed mock theft. In the CIT, wherein eyeblinks are measured simultaneously with autonomic responses, the secret group concealed the crime-related item, whereas the no-secret group did not. As a result, heart rate (HR) was modulated by the intention of concealment in autonomic measures, whereas the effect of concealment on the decrease of eyeblinks was not found to be significant. In addition, the latency of the first eyeblink was longer for the crime-related item in both groups. These results imply that CIT eyeblinks mainly involve the process of selective attention for the item, and the latency of the first eyeblink reflects a delay in attentional disengagement from the item. This study also suggested that there is still room for improvement in simultaneously measuring eyeblinks and autonomic responses in the CIT.