Response Time Concealed Information Test on Smartphones

The Response Time-Based Concealed Information Test (RT-CIT) can reveal when a person recognizes a relevant (probe) item among other, irrelevant items, based on comparatively slower responding to the probe item. Thereby, if a person is concealing the knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be revealed. So far, the RT-CIT has been used only on desktop computers. In Experiment 1 (n = 72; within-subject), we compare the probe-irrelevant differences when using the conventional desktop-based CIT to using a smartphone-based CIT, demonstrating practical equivalence. In Experiment 2 (n = 116; within-subject), we demonstrate that using thumbs for responses (while holding the smartphone) leads to equally efficient CIT results as using conventional index finger responses. At the same time, this second experiment also demonstrates how smartphone-based studies may be efficiently run in large groups, using the participants’ own smartphones. Finally, as an interesting addition, here for the first time we also measured keypress durations (i.e., the time durations of holding down the response keys) in the RT-CIT, which we found to be significantly shorter for probe than for irrelevant items.

Response Time Concealed Information Test on Smartphones

The Response Time-Based Concealed Information Test (RT-CIT) can reveal when a person recognizes a relevant (probe) item among other, irrelevant items, based on comparatively slower responding to the probe item. Thereby, if a person is concealing the knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be revealed. So far, the RT-CIT has been used only on desktop computers. In Experiment 1 (n = 72; within-subject), we compare the probe-irrelevant differences when using the conventional desktop-based CIT to using a smartphone-based CIT, demonstrating practical equivalence. In Experiment 2 (n = 116; within-subject), we demonstrate that using thumbs for responses (while holding the smartphone) leads to equally efficient CIT results as using conventional index finger responses. At the same time, this second experiment also demonstrates how smartphone-based studies may be efficiently run in large groups, using the participants’ own smartphones. Finally, as an interesting addition, here for the first time we also measured keypress durations (i.e., the time durations of holding down the response keys) in the RT-CIT, which we found to be significantly shorter for probe than for irrelevant items.

Information Leakage in the Response Time‐Based Concealed Information Test

The Response Time‐Based Concealed Information Test (RT‐CIT) can reveal when a person recognizes a relevant (probe) item among other, irrelevant items, based on comparatively slower responses to the probe item. For example, if a person is concealing his or her true identity, one can use the suspected identity details as probes, and other, random details as irrelevants. However, in our study, we show that even when participants are merely informed about such probes (i.e., the relevant identity details) before performing the RT‐CIT, their responses will also be slower to these details. Hence, it is more difficult to distinguish such innocent but pre‐informed persons from actually guilty persons. At the same time, we introduce a CIT version with familiarity‐related inducer stimuli, but with no targets, that elicits probe‐minus‐irrelevant RT differences only among guilty participants but not among informed innocent participants. Implications for the theory and the application of CITs are discussed.

Association-based Concealed Information Test: A Novel Reaction Time-Based Deception Detection Method

In recent years, numerous studies were published on the reaction time (RT)-based Concealed Information Test (CIT). However, an important limitation of the CIT is the reliance on the recognition of the probe item, and therefore the limited applicability when an innocent person is aware of this item. In the present paper, we introduce an RT-based CIT that is based on item-category associations: the Association-based Concealed Information Test (A-CIT). Using the participants’ given names as probe items and self-referring “inducer” items (e.g., “MINE” or “ME”) that establish an association between ownership and responses choices, in Experiment 1 (within-subject design; n = 27), this method differentiated with high accuracy between guilty and innocent conditions. Experiment 2 (n = 25) replicated Experiment 1, except that the participants were informed of the probe item in the innocent condition—nonetheless, the accuracy rate remained high. Implications and future possibilities are discussed.

The first independent study on the complex trial protocol version of the P300-based concealed information test: Corroboration of previous findings and highlights on vulnerabilities

More than a dozen studies of the Complex Trial Protocol (CTP) version of the P300-based Concealed Information Test have been published since its introduction (Rosenfeld et al., 2008), and it has been fairly consistently proven to provide high accuracy and strong resistance to countermeasures (Rosenfeld et al., 2013). However, no independent authors have verified these findings until now. In the present, first independent study, we corroborate the accuracy and countermeasure-resistance of the CTP, when the probe item (critical presented information, e.g., crime detail; P) vs. all irrelevant items (Iall) comparison is used for classifying participants as guilty or innocent, but we also show that the CTP is severely vulnerable to countermeasures, when the P vs. the irrelevant item with the largest P300 responses (Imax) comparison is used. This latter measure can be defeated by creating “oddball” items among the irrelevant items (through targeting them with covert responses), and thereby making their P300 responses statistically indistinguishable from those of the probe item. Practical implications are discussed.

Sex hormonal modulation of hemispheric asymmetries in the attentional blink

The present study examines differences in functional cerebral asymmetries modulated by gonadal steroid hormones during the menstrual cycle in women. Twenty-one right-handed women with regular menstrual cycles performed a double-stream rapid serial visual presentation (RSVP) task, with one stream in each visual field, during the low steroid menses and the high steroid midluteal phase. They were required to detect a target item, and then a probe item, each of which could appear in either stream. If the probe item appeared 200 ms after the target, detection of the probe was impaired—a phenomenon known as the “attentional blink.” This occurred in both streams in the midluteal phase, but only in the right visual field during menses. Thus low steroid levels appeared to restrict the attentional blink to the left hemisphere, while high levels of estradiol and progesterone in the midluteal phase appeared to reduce functional asymmetries by selectively increasing the attentional blink in the right hemisphere. This effect appears to be mediated by estradiol rather than progesterone, and it is compatible with the assumption of a hormone-related suppression of right hemisphere functions during the midluteal phase. (JINS, 2005,11, 263–272.)

Use of a Baseline Probe Technique to Monitor the Test Responses of Aphasic Patients

Responses of aphasic patients on a visual discrimination task were monitored using a baseline probe technique. A baseline item was shaped and used as a probe item during the task. Retention of test instructions and fatigue were delineated from item complexity by the probes. Patients responded correctly to probe items during sequences of errors, suggesting that the notion of “temporary imperception” to account for such error clusters is not tenable.