Testing for the Motivation Impairment Effect during Deceptive and Truthful Interaction

According to the motivation impairment effect (MIE) hypothesis, deceivers who are highly motivated to succeed should suffer detrimental effects on nonverbal performance but facilitative effects on verbal performance relative to deceivers who are less motivated. This should make highly motivated deceivers' lies more detectable when receivers have access to nonverbal channels. Burgoon (1998) articulated a number of problems with the reasoning underlying the motivation impairment hypothesis and with the data used to support it. Drawing on a more recent theory of interpersonal deception, the current investigation challenges the MIE hypothesis by advancing the alternative predictions that (a) motivation often enhances both verbal and nonverbal performance and (b) does so irrespective of whether deception or truthtelling is occurring. Results from multiple operationalizations of motivation and performance support these predictions.