Familiarity promotes the blurring of self and other in the neural representation of threat

Abstract

Neurobiological investigations of empathy often support an embodied simulation account. Using functional magnetic resonance imaging (fMRI), we monitored statistical associations between brain activations indicating self-focused threat to those indicating threats to a familiar friend or an unfamiliar stranger. Results in regions such as the anterior insula, putamen and supramarginal gyrus indicate that self-focused threat activations are robustly correlated with friend-focused threat activations but not stranger-focused threat activations. These results suggest that one of the defining features of human social bonding may be increasing levels of overlap between neural representations of self and other. This article presents a novel and important methodological approach to fMRI empathy studies, which informs how differences in brain activation can be detected in such studies and how covariate approaches can provide novel and important information regarding the brain and empathy.

Keywords: emotion; empathy; familiarity; interpersonal relationships; prosocial behavior; social cognition.

Fig. 1

Significant conjunctions between the threat-to-self and threat-to-other conditions on the left, with self–friend overlap indicated in red and self–stranger overlap indicated in blue. On the right, the ‘conjunction of conjunctions’ depicts areas (green) where self–friend and self–stranger conjunctions are themselves conjuncted. (A) Conjunctions in portions of the ACC and AI. (B) The most prominent differences between the two conjunction analyses, showing significant self–friend overlap in the left PFC and significant self–stranger overlap in the right PFC. (C) Conjunctions in portions of the right SMG.

Fig. 2

(A) Bar graphs showing group level means and standard deviations of PSC by condition in the left LPFC (−34.4, 16.3, −2.46). (B) Scatter plots showing the correlation between threat-to-self and threat-to-other PSC in the same region. Note the lack of apparent differences in the group means (A), despite dramatic differences in the correlations between self-threat PSC and other-threat PSC as a function of familiarity (B).

Fig. 3

(A) Bar graphs showing group level means and standard deviations of PSC by condition in the right OFC (37.4, 24.9, −5.6). (B) Scatter plots showing the correlation between threat-to-self and threat-to-other PSC in the same region. Note that here both the group means and individual differences suggest substantial similarity in how the right OFC is processing self-, friend- and stranger-directed threats.

Fig. 4

The significant clusters of activation in (A) a covariance analysis with IOS scale as a covariate predictor and threat-to-friend (threat minus safe contrast) as the dependent variable, and the lack of significant activation in (B) a covariance analysis with IOS scale as a covariate predictor and threat-to-stranger (threat minus safe contrast) as a dependent variable.