Loneliness and the Social Brain: How Perceived Social Isolation Impairs Human Interactions

Abstract

Loneliness is a painful condition associated with increased risk for premature mortality. The formation of new, positive social relationships can alleviate feelings of loneliness, but requires rapid trustworthiness decisions during initial encounters and it is still unclear how loneliness hinders interpersonal trust. Here, a multimodal approach including behavioral, psychophysiological, hormonal, and neuroimaging measurements is used to probe a trust‐based mechanism underlying impaired social interactions in loneliness. Pre‐stratified healthy individuals with high loneliness scores (n = 42 out of a screened sample of 3678 adults) show reduced oxytocinergic and affective responsiveness to a positive conversation, report less interpersonal trust, and prefer larger social distances compared to controls (n = 40). Moreover, lonely individuals are rated as less trustworthy compared to controls and identified by the blinded confederate better than chance. During initial trust decisions, lonely individuals exhibit attenuated limbic and striatal activation and blunted functional connectivity between the anterior insula and occipitoparietal regions, which correlates with the diminished affective responsiveness to the positive social interaction. This neural response pattern is not mediated by loneliness‐associated psychological symptoms. Thus, the results indicate compromised integration of trust‐related information as a shared neurobiological component in loneliness, yielding a reciprocally reinforced trust bias in social dyads.

Social Isolation, Loneliness and Generalized Anxiety: Implications and Associations during the COVID-19 Quarantine

“…Similar consequences (hyperactivation) are found in the insula and locus coeruleus due to inflammation [ 79 , 80 , 86 ]. Interestingly, a reduction in trust-associated activation of the anterior insula and medial prefrontal cortex (the neurocircuits of trust that connect to other limbic regions) was suggested to contribute to the non-trusting, anxious behaviour observed in lonely individuals [ 87 ]. Furthermore, a recent systematic review by Lam et al has highlighted structural and functional differences in the above mentioned regions in terms of loneliness [ 88 ], suggesting that these systems may play a role in both GAD and loneliness.…”

Touched by loneliness—how loneliness impacts the response to observed human touch: a tDCS study

“…, 2020 ). In contrast, other studies show reduced responses of lonely individuals to positive social stimuli ( Lieberz et al. , 2021 ; Saporta et al.…”

Alone Again: Altered Activation in the Observation Execution System during Synchronization in High Loneliness Individuals

“…In functional neuroimaging studies, lonely individuals showed reduced self-other representational similarity in the medial PFC (Courtney & Meyer, 2020). They also exhibited blunted functional connectivity between the AI and occipitoparietal regions during trust decisions (Lieberz et al, 2021). As mentioned above, the AI and the dmPFC are parts of the proposed gap-monitoring system, and structural and functional differences in these areas between high and low loneliness individuals could be linked to alterations of the gap-monitoring system activity.…”

“…They experience more negative feelings during interactions (Hawkley et al, 2003) and report lower relationship satisfaction, more conflict, and less self-disclosure and closeness (Mund et al, 2020). Lonely people also maintain larger interpersonal distance (Lieberz et al, 2021), even from friends (Saporta et al, 2021). A potential component of the failure to fully engage in interactions may be related to difficulties in synchronization.…”

“…Lonely individuals showed reduced self-other representational similarity in the medial PFC (Courtney & Meyer, 2020). They also exhibited blunted functional connectivity between the AI and occipitoparietal regions during trust decisions (Lieberz et al, 2021). Low loneliness individuals had altered functionality of the VS when viewing pleasant social pictures (Cacioppo et al, 2009) and pictures of close-others (Inagaki et al, 2015).…”