The guilty adjustment: Response trends on the symptom validity test

Abstract

Purpose. To our knowledge this was the first experiment that examined response trends over the course of a Symptom Validity Test (SVT). We predicted that the guilty group would avoid being associated with potentially incriminating information, and that they would do this more at the beginning of the test than towards the end.Method. The 86 participants of the guilty group carried out an illegal activity in a room and were instructed to deny having been in that room in a subsequent interview. The 82 innocent participants had never been in that particular room. During the interview the guilty and innocent groups were exposed to a 12-item SVT.Results and Conclusion. As predicted, the guilty participants selected fewer correct (crime related) items than innocents, and this tendency to avoid selecting the correct items was the strongest during the first half of the SVT. The implications of the findings for using an SVT in real life are discussed.Claims of crime amnesia are common in the criminal justice system. Research suggests that somewhere between 20% and 30% of suspects claim to have no recollection of the crime in question

Resistance to coaching in forced‐choice testing

“…Detection accuracy in our naïve condition matched that of other experiments, as did the decline in detection accuracy in our coaching condition for the correct total criterion. As expected in our naïve condition, we found a moderate sensitivity (48%) and good specificity (92%), which matched the range of previous experiments using naïve examinees (Giger et al, ; Jelicic et al, ; Meijer et al, ; Merckelbach et al, ; Orthey et al, ; Shaw et al, ). In the presence of coaching, sensitivity declined (8%), but specificity remained high (100%), matching the findings in Verschuere et al (), reinforcing their conclusion that forced‐choice testing is not resistant to coaching when using correct total criterion.…”

“…Forced‐choice testing (FCT) has been used as a test to detect malingering of sensory impairment (Pankratz, Fausti, & Peed, ). More recently, its use has been extended to detect cases of faked memory loss (e.g., Denney, ; Hiscock & Hiscock, ; Pankratz, ; Van Oorsouw & Merckelbach, ) and concealed information (e.g., Giger, Merten, Merckelbach, & Oswald, ; Meijer, Smulders, Johnston, & Merckelbach, ; Orthey, Vrij, Leal, & Blank, ; Shaw, Vrij, Mann, Leal, & Hillman, ), from which guilty knowledge can be inferred. In the case of concealed information detection, a typical test works as follows: A suspect is presented with a series of questions about the crime.…”

“…However, the detection rate for guilty examinees, sensitivity, is modest at best. More specifically, with a specificity ranging around 95%, sensitivity ranges from 40% to 65% (Giger et al, ; Jelicic, Merckelbach, & van Bergen, ; Meijer et al, ; Merckelbach, Hauer, & Rassin, ; Shaw et al, ). These validity estimates are, however, for participants who are unfamiliar with the test's underlying rationale.…”

Effects of time pressure on strategy selection and strategy execution in forced choice tests

“…Empirical research suggests that examinees with concealed knowledge can successfully be detected at rates varying from 40% to 60% while maintaining a low false positive rate at around 5% (Giger, Merten, Merckelbach, & Oswald, ; Jelicic, Merckelbach, & van Bergen, ; Meijer, Smulders, Johnston, & Merckelbach, ; Merckelbach, Hauer, & Rassin, ; Orthey, Vrij, Leal, & Blank, ; Shaw, Vrij, Mann, Leal, & Hillman, ). This detection accuracy is directly related to the prevalence of three different self‐reported response patterns that examinees with concealed knowledge use to avoid being detected by the test (Orthey et al, ; Orthey, Vrij, Meijer, Leal, & Blank, ).…”

Strategy and Misdirection in Forced Choice Memory Performance Testing in Deception Detection

“…Liars are expected to display underperformance (because they recognize the correct answer and purposefully select the incorrect answer), while truth tellers, who have no knowledge of the event, are expected to score within levels of chance (because they actually guess). Empirical studies report a high (90–100%) classification rate for truth tellers (specificity) (Giger, Merten, Merckelbach, & Oswald, ; Meijer, Smulders, Johnston, & Merckelbach, ; Shaw, Vrij, Mann, Leal, & Hillman, ) and a moderate detection rate (40–63%) for liars (sensitivity) (Giger et al, ; Jelicic, Merckelbach, & van Bergen, ; Meijer et al, ; Merckelbach, Hauer, & Rassin, ; Shaw et al, ). In other words, 90 – 100% of truth tellers typically perform at chance levels, whereas 40 – 63% of liars typically underperform.…”