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Lower delay discounting (better self-control) is linked to higher intelligence, but the basis of this relation is uncertain. To investigate the potential role of working memory (WM) processes, we assessed delay discounting, intelligence (g), WM (span tasks, 3-back task), and WM-related neural activity (using functional magnetic resonance imaging) in 103 healthy adults. Delay discounting was negatively correlated with g and WM. WM explained no variance in delay discounting beyond that explained by g, which suggests that processes through which WM relates to delay discounting are shared by g. WM-related neural activity in left anterior prefrontal cortex (Brodmann's area 10) covaried with g, r= .26, and delay discounting, r=-.40, and partially mediated the relation between g and delay discounting. Overall, the results suggest that delay discounting is associated with intelligence in part because of processes instantiated in anterior prefrontal cortex, a region known to support the integration of diverse information.

We hypothesized that individual differences in intelligence (Spearman's g) are supported by multiple brain regions, and in particular that fluid ( gF) and crystallized ( gC) components of intelligence are related to brain function and structure with a distinct profile of association across brain regions. In 225 healthy young adults scanned with structural and functional magnetic resonance imaging sequences, regions of interest (ROIs) were defined on the basis of a correlation between g and either brain structure or brain function. In these ROIs, gC was more strongly related to structure (cortical thickness) than function, whereas gF was more strongly related to function (blood oxygenation level-dependent signal during reasoning) than structure. We further validated this finding by generating a neurometric prediction model of intelligence quotient (IQ) that explained 50% of variance in IQ in an independent sample. The data compel a nuanced view of the neurobiology of intelligence, providing the most persuasive evidence to date for theories emphasizing multiple distributed brain regions differing in function.

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Relatively little is known about the neural bases of the Big Five personality trait Openness/Intellect. This trait is composed of two related but separable aspects, Openness to Experience and Intellect. On the basis of previous behavioral research (DeYoung, Peterson, & Higgins, 2005), we hypothesized that brain activity supporting working memory (WM) would be related to Intellect but not Openness. To test this hypothesis we used fMRI to scan a sample of 104 healthy adults, as they performed a difficult WM task. Intellect (and not Openness) was found to correlate with WM accuracy and with accuracy-related brain activity, in left lateral anterior prefrontal cortex and posterior medial frontal cortex. Neural activity in these regions mediated the association between Intellect and WM performance, implicating these regions in the neural substrate of Intellect. Intellect was also correlated significantly with scores on tests of intelligence and working memory capacity, but the association of Intellect with brain activity could not be entirely explained by cognitive ability. KeywordsIntellect; Openness; Prefrontal Cortex; Frontopolar Cortex; Working Memory; Intelligence The five factor model or Big Five classifies personality traits into five broad domains: Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness/Intellect. The compound label for the last of these traits reflects an old debate about how best to characterize the content of this domain, with some researchers preferring "Openness to Experience" (e.g., Costa & McCrae, 1992a) and others "Intellect" (e.g., Goldberg, 1993). This debate has been Correspondence concerning this article should be addressed to Colin G. DeYoung; Psychology Department, University of Minnesota, 75 East River Rd., Minneapolis, MN 55455. cdeyoung@umn.edu; or to Jeremy R. Gray, Department of Psychology, Yale University, Box 208205, New Haven, CT 06520; jeremy.gray@yale.edu. Publisher's Disclaimer: The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/journals/psp NIH Public Access Author Manuscript J Pers Soc Psychol. Author manuscript; available in PMC 2010 November 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript largely resolved conceptually by the observation that "Openness" and "Intellect" describe two related but separable aspects of the larger domain (Johnson, 1994;Saucier, 1992). Lexical studies make it clear that both aspects are well represented in natural language and that content related to both appears among the terms loading on a single Big Five factor (e.g., Gold...