Matthiesen, M. | Search bioRxiv

bioRxiv2026

Self-enhancement and devaluation of others during belief formation are linked to narcissistic traits

Background: Narcissistic personality traits are associated with the tendency to maintain a grandiose self-image through self-enhancement and devaluation of others. Using computational modeling, we investigated how narcissistic traits and the experience of pride are linked to how individuals form beliefs about themselves and others. Methods: Healthy individuals and individuals with psychiatric diagnoses varying in narcissistic traits (N = 97) completed a learning task in which self-serving biases emerged implicitly through trial-by-trial belief updating in response to manipulated feedback. Computational modeling quantified how participants updated beliefs about their own and another person's abilities in response to better- and worse-than-expected performance feedback. Results: Higher narcissistic traits were associated with reduced learning from worse-than-expected self-related feedback, consistent with self-enhancement as a mechanism for maintaining a grandiose self-image. Individuals with higher narcissistic traits also reported greater pride following better-than-expected self-related feedback, which mediated the association between narcissistic traits and positive self-related learning. Furthermore, higher narcissistic traits were, mediated via pride, linked to increased learning from worse-than-expected feedback about the other person, suggesting that devaluing others relative to oneself may serve as a secondary pathway for maintaining a grandiose self-image. Discussion: These findings identify computational and affective mechanisms through which narcissistic traits are linked to self- and other-related belief formation. Reduced integration of negative self-related feedback together with enhanced pride following positive feedback may support grandiose self-beliefs, while enhanced learning from negative information about others suggests that individuals with higher narcissistic traits implicitly construct themselves as superior through both self-enhancement and devaluation of others during interpersonal belief formation.

neuroscience↗

bioRxiv2023

Maturation of Nucleus Accumbens Synaptic Transmission Signals a Critical Period for the Rescue of Social Deficits in a Mouse Model of Autism Spectrum Disorder

Social behavior emerges early in development, a time marked by the onset of neurodevelopmental disorders featuring social deficits, including autism spectrum disorder (ASD). Although deficits in social interaction and communication are at the core of the clinical diagnosis of ASD, very little is known about their neural correlates at the time of clinical onset of the disorder. The nucleus accumbens (NAc), a brain region extensively implicated in social behavior, undergoes synaptic, cellular and molecular alterations in early life, and is particularly affected in ASD mouse models. To explore a link between the maturation of the NAc and neurodevelopmental deficits in social behavior, we compared age-dependent changes in spontaneous synaptic transmission in NAc shell medium spiny neurons (MSNs) between the highly social C57BL/6J mouse strain and the idiopathic ASD mouse model BTBR T+ Itpr3tf/J at postnatal day (P) 4, P6, P8, P12, P15, P21 and P30. We found that MSNs from both C57BL/6J and BTBR mice display age-dependent increases in spontaneous excitatory and inhibitory synaptic currents between P4 and P30. Comparison of NAc spontaneous transmission between strains showed that BTBR MSNs display increased excitatory transmission during the first postnatal week, and increased inhibition across the first, second and fourth postnatal weeks, suggesting accelerated maturation of excitatory and inhibitory synaptic inputs onto BTBR MSNs compared to C57BL/6J mice. These early life changes in synaptic transmission are consistent with a potential critical period in the maturation of the NAc, which could maximize the efficacy of interventions affecting social behavior. To test this possibility, we treated BTBR mice in either early life (P4-P8) or adulthood (P60-P64) with the mTORC1 antagonist rapamycin, a well-established rescue intervention for ASD-like behavior. We found that rapamycin treatment rescued social interaction deficits in BTBR mice when injected in infancy, but not in adulthood. These data emphasize the importance of studying brain regions involved in the pathophysiology of neurodevelopmental disorders at clinically-relevant time points, which may offer novel insight into the timing and targets of therapeutic interventions to maximize positive outcomes.

neuroscience↗