Does the Truth Lie in One's Gestures? Relationships Between Gesture, Memory, Personality, and Alternate Facts

Gesture production has been demonstrated to ease cognitive burdens associated with various tasks involving speech. Conversely, lying has been demonstrated to increase cognitive load. There is, however, limited research on whether gestures can alleviate the increased cognitive burden associated with deception. The present study therefore examined whether gesture production during lying eases cognitive load, and whether people were more likely to produce gestures when lying than when telling the truth. The study further examined whether gesture production improved recall for those who told the truth, and ability to integrate false testimony for those who lied. Moderating effects of personality, non-verbal memory and idea generation on gesture production and lying were also assessed. Participants (N = 150, Mage = 22.5, SDage = 7.3) watched a video of a minor crime. At subsequent recall, participants were required to either answer truthfully, or lie. They were also allocated to one of three gesture conditions: Instructed Gesture, No Gesture, or Spontaneous Gesture. While there was no effect of gesture production on perceived cognitive load, participants who told the truth experienced higher cognitive load than participants who lied. Additionally, participants required to tell the truth produced more iconic gestures than participants instructed to lie, but only when explicitly instructed to gesture. Gesture production also supported factual free recall, but did not support participants’ ability to lie. This study’s findings have important implications for the forensic field in understanding the behaviour of liars, as well as theoretical implications regarding lying and gesture production.