Detecting concealed knowledge using a novel attentional blink paradigm.

Traditional concealed information paradigms rely on the idea that stimuli that are meaningful to a person (critical items) will draw attentional resources disproportionately, relative to stimuli that are not (irrelevant items), generating detectable differences on a suitable dependent variable (behavioral, psychophysiological, or neural). Here, we introduce a behavioral paradigm that could be used to reveal concealed information by exploiting the link between concealed information and attentional processes more directly. This novel paradigm is based on the attentional blink phenomenon in which detection of a stimulus reduces detection accuracy rates of subsequent target stimuli within a 200-500 ms time window. We hypothesized that a well-known face used as a critical item could capture attentional resources automatically, making it harder to detect the occurrence of a subsequently presented target face. The results confirmed this hypothesis, and showed that concealed knowledge of a famous face could be detected in 9 out of 12 individuals by looking for a relative dip in target detection accuracy after the presentation of a critical item.