Brain structure links trait conscientiousness to academic performance

Abstract

In the long history of identifying factors to predict academic performance, conscientiousness, a so-called 'big five' personality trait describing self-regulation and goal-directed behavior, has emerged as a stable predictor for this purpose. However, the neuroanatomical substrates of trait conscientiousness and the underlying brain mechanism linking trait conscientiousness and academic performance are still largely unknown. Here, we examined these issues in 148 high school students within the same grade by estimating cortical gray matter volume (GMV) utilizing a voxel-based morphometry method based on structural magnetic resonance imaging. A whole-brain regression analysis showed that trait conscientiousness was positively associated with the GMV in the bilateral superior parietal lobe (SPL) and was negatively associated with the GMV in the right middle frontal gyrus (MFG). Furthermore, mediation analysis revealed that trait conscientiousness mediated the influences of the SPL and MFG volume on academic performance. Importantly, our results persisted even when we adjusted for general intelligence, family socioeconomic status and 'big five' personality traits other than conscientiousness. Altogether, our study suggests that the GMV in the frontoparietal network is a neurostructural marker of adolescents' conscientiousness and reveals a potential brain-personality-achievement pathway for predicting academic performance in which gray matter structures affect academic performance through trait conscientiousness.

Figure 1

Regional gray matter volume (GMV) related to trait conscientiousness. Brain image showing that the superior parietal lobe (SPL) volume was positively correlated with trait conscientiousness. Scatter plots depicting the correlation between trait conscientiousness and left SPL volume (r = 0.30, p < 0.001) and right SPL volume (r = 0.31, p < 0.001). Gender, age and total GMV were regressed out in the analyses.

Figure 2

Regional gray matter volume (GMV) related to trait conscientiousness. Brain image showing that the right middle frontal gyrus (MFG) volume was negatively correlated with trait conscientiousness. Scatter plots depicting the correlation between trait conscientiousness and right MFG volume (r = −0.31, p < 0.001). Gender, age and total GMV were regressed out in the analyses.

Figure 3

Trait conscientiousness mediates the influence of the bilateral SPL (A) and right MFG (B) volume on academic performance. Standardized regression coefficients were presented in the path diagrams. Gender, age and total gray matter volume were regressed out in the models. SPL, superior parietal lobe; MFG, middle frontal gyrus.