To err is human but not deceptive.

This study addresses a poorly understood but important question concerning the cognition of deception: How much more is there to lying than to responding incorrectly, the latter capturing how researchers have occasionally operationalized deception? A recent social-cognitive account of lying - Activation-Decision-Construction-Action Theory (ADCAT) - asserts a qualitative difference between the two - for instance, that deception involves Theory of Mind inferences and more proactive interference. To test these notions within-subjects, participants answered closed-ended and open-ended questions probing general truths honestly, deceptively, or with intentional errors. Response time and noncompliance with instructions were the dependent measures. Deceptive responding generally elicited the longest response times and the lowest instruction compliance, followed by intentional erring, supporting the theory. Although not the primary focus, response inhibition due to implausible deception was demonstrated for the first time.