Vol. 2 No. 6 [Special Issue – March 2012]
Hemispheric Dominance for Deception: A Dual-task Performance Study
Firas Ahmad Al-Hamouri Dept. of Counseling & Educational Psychology College of Education Yarmouk University Irbid, Jordan. Abstract
The vast majority of previous research on deception intended to investigate deception detectionnot the deceptive process per se. This study attempted to investigate the role of left and right hemispheres in deception. Thirty-two (15 males and 17 females) undergraduate students responded to 20 questions truly, and 20 questions deceptively, while finger-tapping with their right/left hand. Results of the study showed greater interference for deception than for truth telling. This main effectwas qualified by a significant hand by condition interaction showing more righthand interference during the deceptive process, implicating more left-hemisphere involvement in deception.
Keywords: deception, hemispheric dominance, finger-tapping, dual-task performance. 1. Introduction
Deception is a common aspect of human social interaction. People admit to lying twice a day, on average(DePaulo, Kashy, Kirkendol, Wyer, & Epstein, 1996), and to using deceit in 14% of emails, 27% of face-to-face interactions and 37% of phone calls according to Hancock (as cited in Brinke, MacDonald, Porter, & O’Connor, 2011). While these acts of deception typically are minor, white lies of little consequence, lies accompanied by powerful emotions and false emotional displays can have major consequencesat individual and societal levels (DePaulo et al., 1996). Deception could be defined as the purposeful misleading of another by using false signals to modify the behavior of a receiver in a way that benefits a sender, at some cost to the receiver (Kozel, Padgett & George, 2004; Semple, & McComb, 1996). Blakemore & Frith (2004) consider deception in the context of a more general ability to inferintentions in the action of others, an ability that is fundamental to the survival of most animals. Gneezy (2005) classifies lies on the base of the consequences that the lie produces into four major categories: lies that help both sides, or at least do not harm anyone, lies that help the other person even if it harms the liar, lies that do not help the liar but can harm both sides or, at the veryleast, the other person and finally, lies that increase the payoff to the liar and decrease the payoff to the other party. Ekman (1997) talks about two criteria for distinguishing lies from other kinds of deception; the liar intention and the target's information about this intention. On one hand the liar deliberately chooses to mislead the target, he may actually tell the truth, but that is not hisintent, and on the other hand, the target is not notified about the liar’s intention to mislead. The ability to correctly detect truths and lies is of crucial importance in many applied settings, and is an important task for professionals such as jurors, judges, police officers, lawyers, and psychologists in their daily work (Forgas & East, 2008). Therefore, in recent years, much effort has beendevoted to developing methods of measurement that can accurately depict the act of deception, and various approaches to psychophysiological detection of deception have been developed (National Research Council, 2002). Most lie detection tools used to date are arousal-based protocols. The majority of these protocols are based on the assumption that, because of their fear of being caught, liars willbe more aroused when answering key relevant questions than when answering comparison questions (Vrij, Fisher, Mann, & Leal, 2006). Methods of detecting deception include the polygraph that measures changes in skin conductivity and variations in the heart rate and respiration rate, methods of physiological measurement, such as biofeedback and electroencephalography, psychological instruments...