Neural congruence between intertemporal and interpersonal self-control: Evidence from delay and social discounting

- Delay and social discounting engaged highly overlapping neural networks.
- Overlapping activity in limbic, executive, and default regions was observed.
- Social discounting uniquely recruited areas of the default network.
- Hippocampal and insula activity characterized high discounters.
- Medial prefrontal and temporoparietal activity characterized low discounters.

Behavioral studies using delay and social discounting as indices of self-control and altruism, respectively, have revealed functional similarities between farsighted and social decisions. However, neural evidence for this functional link is lacking. Twenty-five young adults completed a delay and social discounting task during fMRI scanning. A spatiotemporal partial least squares analysis revealed that both forms of discounting were well characterized by a pattern of brain activity in areas comprising frontoparietal control, default, and mesolimbic reward networks. Both forms of discounting appear to draw on common neurocognitive mechanisms, regardless of whether choices involve intertemporal or interpersonal outcomes. We also observed neural profiles differentiating between high and low discounters. High discounters were well characterized by increased medial temporal lobe and limbic activity. In contrast, low discount rates were associated with activity in the medial prefrontal cortex and right temporoparietal junction. This pattern may reflect biological mechanisms underlying behavioral heterogeneity in discount rates.