Intelligence

General Intelligence

General intelligence addresses the brain's executive functions: the ability to think abstractly, plan, reason, and solve problems, among others. This is the form of intelligence that many intelligence quotient (IQ) tests measure. The executive [Page 518]functions are primarily governed by the neocortex area of the brain, and evidence suggests that this region is a primary enabler of deceptive ability.

Across animal species, the development of the neocortex is correlated with increasing abilities at deception. In human children, the neocortex develops later than the rest of the brain, at around 4 or 5 years of age, and its maturation is a critical step in children's acquisition of deception skills. In imaging studies of adult human brains, the neocortex is highly active during the production of lies.

The brain's executive functions are taxed during deception because, compared with truth-tellers, liars must engage in more cognitive effort to create an utterance. Liars must remain aware of, but suppress, the truth while simultaneously fabricating a deceptive account that is plausible. Various models of lying behavior, such as the interpersonal deception theory and the activation-decision-construction model of lying, converge on the proposition that lying is harder on the brain than truth-telling.

In particular, the generation of a lie relies on certain aspects of executive functioning: inhibitory control and working memory. Inhibitory control is used to suppress behaviors that would indicate the truth or not support the deception attempt. Working memory is engaged in order to maintain awareness of both reality and the details of the lie being constructed. Studies of children suggest that weak executive functioning inhibits the ability to deceive at all, much less deceive skillfully.

Generally, research on executive function in children and lying behavior has been mixed. Research on young children has shown that those with higher executive functions may deceive more frequently. However, this may simply indicate the inability of children with undeveloped minds to conceptualize deception. Results from research with children (ages 4 to 16) who are old enough to conceptualize deception is mixed, with only some studies finding positive correlations between executive function and lying rates. A study of 8-to 16-year-olds found that those with higher executive functioning created more sophisticated lies but did not lie more often.

Not all lies are equally taxing. Some lies, such as those involving complex descriptions of reality, require more cognitive effort. Similarly, liars who are questioned by the lie recipient face greater burdens on their cognitive ability, as they may have to come up with information and sustain an increasingly complex account. However, “white lies” may require less cognitive effort, and deception based on omission or equivocation is also less demanding. Liars who have time to prepare ahead of time also generate more convincing lies, presumably because thinking ahead can lessen the cognitive load. In situations where there are fewer demands on a liar's mind during the production of the lie, general intelligence is likely to be less helpful.

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