De hand in eigen boezem: Vier hindernissen voor de forensische psychologie

Rede, in verkorte vorm uitgesproken ter gelegenheid van het aanvaarden van het ambt van bijzonder hoogleraar Rechtspsychologie aan de Erasmus Universiteit Rotterdam vanwege het Trustfonds EUR op 14 maart 2008. Juristen maken regelmatig gebruik van psychologische inzichten. Zo vraagt de rechter aan gedragswetenschappelijk deskundigen of een verdachte toerekeningsvatbaar is en of een getuigenverklaring geloofwaardig is. Toch kunnen ze dat soms maar beter niet doen, aldus prof.mr.dr. Eric Rassin

The effect of confession evidence on conviction, and considering alternative scenarios as remedy in a sample of police officers

In order to prevent tunnel vision and ultimately miscarriages of justice, police, prosecutors and judges must remain open to alternative scenarios in which the suspect is in fact innocent. However, it is not evident from the literature that people are sufficiently aware of how alternative scenarios should be employed in the decision making process. In the present research, 230 Dutch police officers read one of three versions of a case description. In the first version, there was strong evidence against the primary suspect. In the second version, the suspect additionally confessed, increasing the body of incriminating evidence. In the third version, the suspect confessed, but before deciding on their conviction, participants were instructed to consider how well each piece of evidence fitted in the primary but also in the alternative scenario (in which the crime was committed by an alternative suspect). Contrary to expectations, the confession did not increase conviction and the alternative-scenario consideration did not suppress conviction. Implications of these null findings are discussed.</p

The effect of confession evidence on conviction, and considering alternative scenarios as remedy in a sample of police officers

In order to prevent tunnel vision and ultimately miscarriages of justice, police, prosecutors and judges must remain open to alternative scenarios in which the suspect is in fact innocent. However, it is not evident from the literature that people are sufficiently aware of how alternative scenarios should be employed in the decision making process. In the present research, 230 Dutch police officers read one of three versions of a case description. In the first version, there was strong evidence against the primary suspect. In the second version, the suspect additionally confessed, increasing the body of incriminating evidence. In the third version, the suspect confessed, but before deciding on their conviction, participants were instructed to consider how well each piece of evidence fitted in the primary but also in the alternative scenario (in which the crime was committed by an alternative suspect). Contrary to expectations, the confession did not increase conviction and the alternative-scenario consideration did not suppress conviction. Implications of these null findings are discussed.</p

False Confessions in the Lab: A Review

__Abstract__ Intuitively, confession is a strong piece of evidence, because it appears unlikely that a suspect would confess to a crime he did not commit, thereby acting against his own best interest. Surprisingly, experimental studies show that innocent and well-educated individuals do tend to confess falsely when questioned about something they did not in fact do. In this contribution, an overview is presented of the experimental research on confession evidence. Limitations and implications of the scientific insights are discussed

Dark personality traits and deception, and the short dark tetrad (SD4) as integrity screening instrument

Dark personality traits (Machiavellianism, Narcissism, Psychopathy, and Sadism) have been associated with aversive, unethical, and criminal conduct. Concise measurement tools such as the Short Dark Tetrad (SD4) are popular, because they lend themselves as screening instruments. As such, the scores on these scales are used in various decision-making contexts, and they can have considerable effects on the lives of people who display an unfortunate scoring pattern. The present study explored to what extent high SD4 scores are actually predictive of deceptive behaviour in a matrix puzzle task, in a general community sample (N = 751). Results indicated that 9.9% of participants lied, that is, exaggerated their performance on the matrix task, hoping to increase their likelihood of financial reward. These cheating participants scored higher on all four dark traits. Nonetheless, the overlap between SD4 distributions made it impossible to determine cut-off scores in an attempt to consider scores as actual predictors of deception proneness. When framed in likelihoods, some scores can be diagnostic of deception proneness. Particularly in the context of statement validity assessment, characterized by tools with modest to poor accuracy, SD4 scores may add to diagnostic accuracy.</p

Psychopathy as a predisposition to lie hedonistically

Excessive lying is generally considered to be a hallmark of psychopathy. Meanwhile, the empirical evidence for the association between psychopathy and lying is somewhat limited. In the present study, non-clinical volunteers completed a measure of psychopathy, and were then brought in an experimental situation (a puzzle task) in which they could opt to lie for potential personal gain (i.e. monetary reward). Findings suggest that 19% of participants (i.e. 31 out of 166) lied about their performance in the puzzle task, thus increasing their likelihood of gaining additional reward. These lying participants scored significantly higher on psychopathy than did their honest peers. Thus, the findings support the hypothesis that psychopathy is characterised by deceitful behaviour. Particularly, psychopathic boldness was associated with lying.</p

The effect of HD-tDCS on brain oscillations and frontal synchronicity during resting-state EEG in violent offenders with a substance dependence

Violence is a major problem in our society and therefore research into the neural underpinnings of aggression has grown exponentially. Although in the past decade the biological underpinnings of aggressive behavior have been examined, research on neural oscillations in violent offenders during resting-state electroencephalography (rsEEG) remains scarce. In this study we aimed to investigate the effect of high-definition transcranial direct current stimulation (HD-tDCS) on frontal theta, alpha and beta frequency power, asymmetrical frontal activity, and frontal synchronicity in violent offenders. Fifty male violent forensic patients diagnosed with a substance dependence were included in a double-blind sham-controlled randomized study. The patients received 20 minutes of HD-tDCS two times a day on five consecutive days. Before and after the intervention, the patients underwent a rsEEG task. Results showed no effect of HD-tDCS on the power in the different frequency bands. Also, no increase in asymmetrical activity was found. However, we found increased synchronicity in frontal regions in the alpha and beta frequency bands indicating enhanced connectivity in frontal brain regions as a result of the HD-tDCS-intervention. This study has enhanced our understanding of the neural underpinnings of aggression and violence, pointing to the importance of alpha and beta frequency bands and their connectivity in frontal brain regions. Although future studies should further investigate the complex neural underpinnings of aggression in different populations and using whole-brain connectivity, it can be suggested with caution, that HD-tDCS could be an innovative method to regain frontal synchronicity in neurorehabilitation.</p

The effect of HD-tDCS on brain oscillations and frontal synchronicity during resting-state EEG in violent offenders with a substance dependence

Violence is a major problem in our society and therefore research into the neural underpinnings of aggression has grown exponentially. Although in the past decade the biological underpinnings of aggressive behavior have been examined, research on neural oscillations in violent offenders during resting-state electroencephalography (rsEEG) remains scarce. In this study we aimed to investigate the effect of high-definition transcranial direct current stimulation (HD-tDCS) on frontal theta, alpha and beta frequency power, asymmetrical frontal activity, and frontal synchronicity in violent offenders. Fifty male violent forensic patients diagnosed with a substance dependence were included in a double-blind sham-controlled randomized study. The patients received 20 minutes of HD-tDCS two times a day on five consecutive days. Before and after the intervention, the patients underwent a rsEEG task. Results showed no effect of HD-tDCS on the power in the different frequency bands. Also, no increase in asymmetrical activity was found. However, we found increased synchronicity in frontal regions in the alpha and beta frequency bands indicating enhanced connectivity in frontal brain regions as a result of the HD-tDCS-intervention. This study has enhanced our understanding of the neural underpinnings of aggression and violence, pointing to the importance of alpha and beta frequency bands and their connectivity in frontal brain regions. Although future studies should further investigate the complex neural underpinnings of aggression in different populations and using whole-brain connectivity, it can be suggested with caution, that HD-tDCS could be an innovative method to regain frontal synchronicity in neurorehabilitation.</p