Lieberman, M. (in press). Intuition: A social cognitive neuroscience approach. Psychological Bulletin.

Using a social cognitive neuroscience approach, this review proposes that implicit learning processes are the cognitive substrate of intuition. This hypothesis is supported by (a) an examination of the conceptual correspondence between implicit learning and intuition in social psychological processes (nonverbal communication); (b) an examination of the neuroanatomical substrate of intuition and implicit learning through a review of neuropsychological (Huntington's and Parkinson's disease), neuroimaging, neurophysiological and neuroanatomical data. It is concluded that the caudate and putamen, in the basal ganglia, are the central components of both intuition and implicit learning thus supporting the proposed relationship. In addition, parallel but distinct processes of judgment and action are demonstrated at each of the social, cognitive and neural levels of analysis. The review also suggests that explicit attempts to learn a sequence can interfere with implicit learning. The possible relevance of the computations of the basal ganglia to emotional appraisal, automatic evaluation, script processing and decision making are discussed.

Lieberman, M. (in press). Introversion and working memory: Central executive differences. Personality and Individual Differences.

The relationship between introversion and working memory was tested. Prior studies have either not focused directly on working memory or have focused only on the storage component of working memory. Neuroanatomical and neurochemical relationships between dorsolateral prefrontal cortex and the reticular formation suggest that the executive component of working memory is the most likely to differ across introverts and extraverts. Using Sternberg's (1975) memory scanning paradigm, which taps the central executive component of working memory, results indicate that introverts are slower than extraverts in comparing the contents of working memory to an external target. Social psychological consequences of this central executive difference in working memory are discussed.

Lieberman, M., Ochsner, K., Gilbert, D. T., & Schacter, D. L. (in preparation). Attitude change in amnesics: A social cognitive neuroscience approach. To be submitted to Psychological Science.

Engaging in a behavior that conflicts with pre-existing attitudes (e.g. expressing a preference for an imperfect item) often results in a change in those attitudes so that they no longer conflict with the action taken (we like that item more than we did initially). Most accounts of such behavior-induced attitude change, including cognitive dissonance theory and self-perception theory, implicitly assume that the change follows from conscious reasoning that draws on a) explicit memory for the counter-attitudinal behavior and b) conscious and resource-demanding processing of the conflicting cognitions. Two experiments challenged these assumptions and tested the hypothesis that behavior-induced attitude change can be supported by automatic information processing mechanisms. The first demonstrated that in the absence of explicit memory for their attitude-discrepant behavior amnesiacs show as much attitude change as their matched controls. The second demonstrated that the magnitude of attitude change was not diminished by a cognitive load manipulation that impaired conscious processing and explicit memory. These studies illustrate the benefits of employing a social cognitive neuroscience approach which combines social psychological and cognitive neuroscientific theories and methods.

Lieberman, M., & Rosenthal, R. (under review). Why introverts can't always tell who likes them: Social multi-tasking and nonverbal decoding. Submitted to Journal of Personality and Social Psychology.

Theories of personality suggest that extraverts are particularly able social creatures and thus good candidates to be highly skilled nonverbal decoders. Most studies, however, have not found a positive correlation between extraversion and nonverbal decoding. I propose that although there is no inherent decoding ability difference between introverts and extraverts, introverts are less able to engage in social multi-tasking, and thus are poorer at nonverbal decoding when it is a secondary task. Prior research has uniformly extracted the nonverbal decoding out of its social multi-tasking context and consequently never tested this hypothesis. In study 1, participants engaged in nonverbal decoding in or out of a social multi-tasking context. In study 2, participant goals were manipulated such that nonverbal decoding was either a primary or secondary goal during a social interaction. Study 3 replicated the findings of studies 1 and 2 in a more controlled, but less social, multi-tasking environment. In studies 1-3, introverts exhibited a nonverbal decoding deficit, relative to extraverts, but only when decoding was a secondary, rather than primary, task within a multi-tasking context. In study 4, participants performed two tasks that relied on either the central executive or storage component of working memory. Extraversion was correlated with central executive efficiency (r=.42), but not with storage capacity (r=.04). These results suggest that the less efficient central executive component of working memory in introverts leaves them less able to effectively engage in social multi-tasking.