One of several theories that attempt to explain the underlying mechanisms of PDD. According to conflict theory, the simultaneous activation of two conflicting tendencies, such as the motivations to lie and tell the truth, results in physiologic arousal. The greater the conflict, the larger will be the response. This explanation arises from the work of Luria in the 1920s and 1930s. The conflict theory predicts that psychopaths, by virtue of a defective conscience, do not produce arousal responses as large as non-psychopaths, and this effect has been demonstrated in laboratory studies for psychopaths as a group. However, it does not explain well why phasic responses occur even when an examinee is not required to answer the question, or even when the examinee answers truthfully. The conflict theory is rarely cited as the principal explanation for PDD. See: Gardner (1937).