McCornack-Parks Model

The McCornack-Parks Model is a model of deception detection conceptualized by communication scholars Steven McCornack and Malcolm R. Parks. Broadly described, the model posits that increases in relational intimacy lead to decreases in deception detection ability. However, the relationship between these variables is argued to be indirect, mediated by confidence in detection ability and truth bias.

The model derives from work McCornack conducted as a part of his senior honors thesis at the University of Washington, under the supervision of Parks. McCornack was interested in exploring the impact that increases in romantic intimacy had upon accuracy in deception detection. At that point in time (the early 1980s), only a handful of previous studies had explored the effects of intimacy upon accuracy—with mixed results. One line of research, authored by Randy Brandt and his colleagues, had investigated the detection abilities of strangers, manipulating “familiarity” through repeated exposure to the truthful behaviors of message sources. They found a curvilinear effect for such familiarity on detection accuracy, such that increases in the number of exposures to truthful source behavior increased accuracy in detecting deception to a certain point, after which additional exposures resulted in decreased accuracy.

Other scholars had examined actual relational partners, comparing accuracy across different types of involvements. Mark Comadena, for example, had studied the comparative detection accuracy of marital spouses versus friends, finding that spouses had higher accuracy. In contrast, Gerald Miller and his colleagues found little difference in detection accuracy between spouses, close friends, and strangers.

McCornack and Parks argued that one reason for the conflicting findings was that the relationship between familiarity and accuracy was indirect, mediated by two variables. The first of these was confidence in detection ability. The second was a variable that would come to be widely studied and cited within the field of deception: a bias toward consistently perceiving a partner as truthful, that McCornack and Parks labeled “truth bias.”

McCornack and Parks concluded that these variables likely were causally interdependent. Specifically, they reasoned that increases in relational intimacy would lead partners to believe that they could, in fact, detect their partners' lies (that is, confidence in detection ability). At the same time, this increase in confidence would be associated directly with an increased belief that their partners would never lie. McCornack and Parks argued that if individuals believe they can always catch their partners' lies, they are more likely to process partners' communication heuristically and presume associated positive beliefs, such as “my partner is always telling me the truth” (that is, truth bias).

Truth bias, in turn, should be directly negatively related to accuracy in detecting deception. That is, if people believe that their partners never lie, they will not detect their partners' lies when they do occur. The practical implication of the proposed model, in toto, is that individuals involved in romantic relationships should believe that they can detect their partners' lies, should believe that their partners would never lie to them, and should have decidedly low deception detection accuracy.

Using partial correlations, McCornack and Parks tested this causal string in data they collected from 60 romantically involved college dating couples. Their results confirmed their proposed model. A conference paper based on their results subsequently won Top Paper in the Interpersonal Division of the International Communication Association and was published the following year in Communication Yearbook 9.

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