Countering information leakage in the Concealed Information Test: The effects of item detailedness.

Concealed Information Tests (CIT) are administered to verify whether suspects recognize certain features from a crime. Whenever it is presumed that innocent suspects were contaminated with critical information (e.g., the perpetrator had a knife), the examiner may ask more detailed questions (e.g., specific types of knives) to prevent false positives. However, this may increase the number of false negatives if the true perpetrator fails to discern specific details from its plausible irrelevant controls, or because detailed crime-scene information may be forgotten. We examined whether presenting items at the exemplar level protects against contamination, and whether it compromises the sensitivity in a physiological CIT. Participants (N = 142) planned a mock-robbery, with critical items encoded either at the category or at the exemplar level. The CIT was administered immediately or after a 1-week-delay, with questions phrased at the categorical or exemplar level. There were no effects of time delay. Results revealed that when item detailedness was congruent at encoding and testing, the SCR, HR, and RLL showed larger differential responses, as compared with incongruent conditions. Participants contaminated with crime knowledge at the categorical level did not show a CIT-effect for crime details at the exemplar level, suggesting detailed questions may counter the leakage problem. Asking questions at the exemplar level did not reduce the CIT detection efficiency as compared to asking questions at the categorical level. The importance of congruency between encoding and testing provides examiners with a challenge, as it is difficult to estimate how details are naturally encoded.

Distinguishing true from false confessions using physiological patterns of concealed information recognition - A proof of concept study.

Wrongful conviction cases indicate that not all confessors are guilty. However, there is currently no validated method to assess the veracity of confessions. In this preregistered study, we evaluate whether a new application of the Concealed Information Test (CIT) is a potentially valid method to make a distinction between true and false admissions of guilt. Eighty-three participants completed problem-solving tasks, individually and in pairs. Unbeknownst to the participants, their team-member was a confederate, tempting the participant to break the experimental rules by assisting during an individual assignment. Irrespective of actual rule-breaking behavior, all participants were accused of cheating and interrogated. True confessors but not false confessors showed recognition of answers obtained by cheating in the individual task, as evidenced by larger physiological responses to the correct than to plausible but incorrect answers. These findings encourage further investigation on the use of memory detection to discriminate true from false confessions.

It's a match!? Appropriate item selection in the Concealed Information Test.

BACKGROUND: While the Concealed Information Test (CIT) can determine whether examinees recognize critical details, it does not clarify the origin of the memory. Hence, when unknowledgeable suspects are contaminated with crime information through media channels or investigative interviews, the validity of the CIT can be compromised (i.e. false-positive outcomes). Yet, when the information was disclosed solely at the category level (e.g. the perpetrator escaped in a car), presenting specific items at the exemplar level (e.g. Citroën, Opel, or Volkswagen) might preclude this problem. However, diminished recollection for exemplar-level details could attenuate the CIT effect for knowledgeable suspects, thereby leading to false negatives. The appropriate item level for memory detection to reach an optimal balance between sensitivity and specificity remains elusive. As encoding, retention, and retrieval of information may influence memory performance and thereby memory detection, the current study investigated the validity of the CIT on both categorical and exemplar levels. RESULTS: Participants planned a mock robbery (n = 165), with information encoded at the category (e.g. car) or exemplar (e.g. Citroën) level. They were tested immediately or after a one-week-delay, with a response time-based CIT consisting of questions at the categorical or exemplar level. An interaction was found between encoding and testing, such that CIT validity based on reaction time was higher for "matching" (e.g. exemplar-exemplar) than for "mismatching" (e.g. exemplar-categorical) items, while immediate versus one week delayed testing did not affect the outcome. CONCLUSION: Critically, this indicates that what constitutes a good CIT item depends on the way the information was encoded. This provides a challenge for CIT examiners when selecting appropriate items.

Self-initiated versus instructed cheating in the physiological Concealed Information Test.

The validity of the Concealed Information Test (CIT) to detect recognition of critical details has been demonstrated in hundreds of laboratory studies. These studies, however, lack the factor of deliberate intent to deceive. This disparity between research and practice may affect the generalizability of laboratory based CIT findings. In the current study, 65 out of 174 participants cheated on their own initiative in a trivia quiz. These self-initiated cheaters were compared to 68 participants who were explicitly requested to cheat. Skin conductance, heart rate, and respiration were found to detect concealed information related to cheating. No significant differences emerged between self-initiated and instructed cheaters, supported by Bayesian statistics showing substantial evidence for the null hypothesis. The data demonstrate that the validity of the CIT is not restricted to instructed deception. This finding is encouraging from an ecological validity perspective and may pave the way for further field implementation of memory detection.