Motivation impairment effect

Motivation impairment effect (MIE) is a hypothesised behavioral effect relating to the communication of deception. The MIE posits that people who are highly motivated to deceive are less successful in their goal (compared to those who are less motivated) when their speech and mannerisms are observed by the intended audience. This is because their nonverbal cues, such as adaptor gestures, sweating, kinesic behaviors, verbal disfluencies, etc., tend to be more pronounced due to increased stress, cognitive load, and heightened emotional state. There is some disagreement regarding the MIE hypothesis, with a few nonverbal communication scholars arguing that deception should not be examined as separate for senders and receivers, but rather as an integral part of the overall process.

Hypothesis

The MIE hypothesis associated with deceptive communication predicts that relative to those who are less motivated, those who are more highly motivated to get away with their deception may be better at the verbal aspects of their deception, but comparatively less successful when others can observe their nonverbal behaviors. Thus, lies told by motivated liars should be more readily detected than lies told by unmotivated liars, as Iong as the judges of the lie can see or hear the speakers' nonverbal and verbal cues. Therefore, a negative association is predicted between motivation and deception performance, but only when the observer has direct access to the deceiver's nonverbal cues.

When only verbal channels are accessible, predictions are that performance is improved by motivation. The motivation impairment effect is founded on basis that deception is associated with heightened mental, emotional, and cognitive responses caused by emotions of fear of being discovered, guilt, and feeling uncomfortable.

Alternative hypothesis

Interpersonal deception theory (Burgoon et al., 1995) has more recently generated research challenging DePaulo & Kirkendol's motivation impairment effect hypothesis.