General intelligence and memory span: Evidence for a common neuroanatomic framework

Abstract

General intelligence (g) is highly correlated with working-memory capacity (WMC). It has been argued that these central psychological constructs should share common neural systems. The present study examines this hypothesis using structural magnetic resonance imaging to determine any overlap in brain areas where regional grey matter volumes are correlated to measures of general intelligence and to memory span. In normal volunteers (N = 48) the results (p < .05, corrected for multiple comparisons) indicate that a common anatomic framework for these constructs implicates mainly frontal grey matter regions belonging to Brodmann area (BA) 10 (right superior frontal gyrus and left middle frontal gyrus) and, to a lesser degree, the right inferior parietal lobule (BA 40). These findings support the nuclear role of a discrete parieto-frontal network.

Keywords:

• General intelligence
• Memory span
• Magnetic resonance imaging
• Voxel-based morphometry
• Working-memory capacity.

Acknowledgments

We thank Kevin Head for the assistance with data analyses. The University of California, Irvine (UCI) portion of this work was funded in part by a grant from the National Institute of Child Health and Human Development (NICHD) to Dr. Haier (HD037427). The MIND Institute portion of this work was supported in part by a generous donation from Carl and Ann Hawk (Sandia National Laboratories, retired). The Universidad Autónoma de Madrid (UAM) portion of this work was funded in part by a grant from the Ministerio de Educación y Ciencia (MEC) to R. Colom (SEJ–2006–07890).

Notes

¹ Very recently, Unsworth and Engle (in press) wrote: “we conclude, as a matter of parsimony, that simple and complex span largely measure the same basic processes, and we reject the notion that short-term memory and working memory are different constructs.”