Intelligence and Extraversion in the neural evaluation of delayed rewards

• Time discounting (TD) is the preference for small early over large delayed rewards.
• TD is predicted positively by Intelligence (IQ) and negatively by Extraversion (E).
• Separate neural signals of reward sensitivity are differentially correlated with IQ and E.
• Personality traits are crucial to understand variations in reward mechanisms.

Temporal discounting (TD), the preference for earlier, smaller rewards over delayed, larger rewards, is a pervasive phenomenon that covaries with Big Five personality traits and Intelligence (IQ). This study provides novel insight by identifying correlates for IQ and Extraversion in the neural representation of TD preferences. An intertemporal choice task was employed, where offers were sequentially presented, distinguishing between one evaluation phase (first offer is presented) and one comparison phase (second offer is presented and values are compared). IQ correlated with responses of caudate nucleus to the subjective values of the offers, suggesting a role of cognitive abilities in modulating reward responses. Extraversion correlated with the strength of functional connectivity of a reward evaluation network centered on ventromedial prefrontal cortex.