What are you hiding? The underlying and contributing mechanisms of physiological memory detection

The notion that physiological and behavioral measures can be used to detect concealed memories is intriguing, to say the least. Although years of research on the Concealed Information Test (CIT) have proven the validity of this method, it also raised new questions. The present dissertation focused on three questions that shared a common desire to deepen our understanding of the memory detection phenomenon. First, what are the mechanisms underlying the differential responses to concealed memory items? The experiments presented in Chapters 1 and 2 revealed that while the skin conductance measure reflects orientation to the critical items, the respiration and heart rate measures reflect attempts at arousal inhibition. Second, is the CIT only sensitive to explicit memory or also to implicit memory? The experiments presented in Chapter 3 provided no compelling evidence for the CIT’s sensitivity to implicit memory and showed that the test’s validity depends to a large extent on explicit recognition. Third, does the emotional value of the concealed items affect detection efficiency? The experiments presented in Chapter 4 indicate that both memory and CIT detection efficiency with the skin conductance measure may be heightened for emotional compared to neutral pictures, whereas detection based on heart rate and respiration is unaffected by the emotional level of the items. Taken together, the present results provide novel insights in the theoretical underpinnings of the CIT, with a fractionation of the physiological measures, and help mapping the factors that contribute to successful detection of concealed memory items.