Age-related differences in the activation of the mentalizing- and reward-related brain regions during the learning of others' true trustworthiness

The anatomical structure of sex differences in trust propensity: A voxel-based morphometry study

Trust is a key component of human relationships. Sex differences in trust behavior have been elucidated by parental investment theory and social role theory, attributing men's higher trust propensity to their increased engagement in physically and socially risky activities aimed at securing additional resources. Although sex differences in trust behavior exist and the neuropsychological signatures of trust are known, the underlying anatomical structure of sex differences is still unexplored. Our study aimed to investigate the anatomical structure of sex differences in trust behavior toward strangers (i.e., trust propensity, TP) by employing voxel-based morphometry (VBM) in a sample of healthy young adults. We collected behavioral data for TP as measured with participants in the role of trustors completing the one-shot trust game (TG) with anonymous partners as trustees. We conducted primary region of interest (ROI) and exploratory whole-brain (WB) VBM analyses of high-resolution structural images to test for the association between TP and regional gray matter volume (GMV) associated with sex differences. Confirming previous studies, our behavioral results demonstrated that men trusted more than women during the one-shot TG. Our WB analysis showed a greater GMV related to TP in men than women in the precuneus (PreC), whereas our ROI analysis in regions of the default-mode network (dorsomedial prefrontal cortex [dmPFC], PreC, superior temporal gyrus) to simulate the partner's trustworthiness, central-executive network (ventrolateral PFC) to implement a calculus-based trust strategy, and action-perception network (precentral gyrus) to performance cost-benefit calculations, as proposed by a neuropsychoeconomic model of trust. Our findings advance the neuropsychological understanding of sex differences in TP, which has implications for interpersonal partnerships, financial transactions, and societal engagements.

Age-group differences in trust-related decision-making and learning

Facial impressions contribute to evaluations of trustworthiness. Older adults are especially vulnerable to trust violations, incurring risks for deception and exploitation. Using the newly developed social Iowa Gambling Task (S-IGT), we examined age-group differences in the impact of facial trustworthiness on decision-making and learning. In the congruent condition (CS-IGT), advantageous decks were paired with trustworthy faces and disadvantageous decks with untrustworthy faces. In the incongruent condition (IS-IGT), this pairing was reversed. Younger (n = 143) and older (n = 129) participants completed either the standard Iowa Gambling Task (IGT), CS-IGT, or IS-IGT. Both age groups preferred trustworthy faces in their initial choices. Older adults performed worse than younger adults across all tasks over time. Further, compared to younger adults, older adults performed worse on the IS-IGT, suggesting that incongruent facial cues interfered with older adults' performance, which aligns with reduced sensitivity to negative social reputations in aging. Multilevel modeling also indicated that age-group differences were most pronounced across all tasks in the last 40 trials. Together these findings suggest that differences between younger and older adults in experience-dependent decision-making are magnified in social contexts that involve a "wolf in sheep's clothing," which may reflect age-related difficulties in integrating incongruent information.

Age-related differences in the social associative learning of trust information

Trust is a key component of social interaction. Older adults, however, often exhibit excessive trust relative to younger adults. One explanation is that older adults may learn to trust differently than younger adults. Here, we examine how younger (N = 33) and older adults (N = 30) learn to trust over time. Participants completed a classic iterative trust game with 3 partners. Younger and older adults shared similar amounts but differed in how they shared money. Compared to younger adults, older adults invested more with untrustworthy partners and less with trustworthy partners. As a group, older adults displayed less learning than younger adults. However, computational modeling suggests that this is not because older adults learn differently from positive and negative feedback than younger adults. Model-based fMRI analyses revealed several age- and learning-related differences in neural processing. Specifically, we found that older learners (N = 19), relative to older non-learners (N = 11), had greater reputation-related activity in metalizing/memory areas while making their decisions. Collectively, these findings suggest that older adult learners use social cues differently from non-learners.

Evaluating Effective Connectivity of Trust in Human-Automation Interaction: A Dynamic Causal Modeling (DCM) Study

OBJECTIVE

Using dynamic causal modeling (DCM), we examined how credibility and reliability affected the way brain regions exert causal influence over each other-effective connectivity (EC)-in the context of trust in automation.

BACKGROUND

Multiple brain regions of the central executive network (CEN) and default mode network (DMN) have been implicated in trust judgment. However, the neural correlates of trust judgment are still relatively unexplored in terms of the directed information flow between brain regions.

METHOD

Sixteen participants observed the performance of four computer algorithms, which differed in credibility and reliability, of the system monitoring subtask of the Air Force Multi-Attribute Task Battery (AF-MATB). Using six brain regions of the CEN and DMN commonly identified to be activated in human trust, a total of 30 (forward, backward, and lateral) connection models were developed. Bayesian model averaging (BMA) was used to quantify the connectivity strength among the brain regions.

RESULTS

Relative to the high trust condition, low trust showed unique presence of specific connections, greater connectivity strengths from the prefrontal cortex, and greater network complexity. High trust condition showed no backward connections.

CONCLUSION

Results indicated that trust and distrust can be two distinctive neural processes in human-automation interaction-distrust being a more complex network than trust, possibly due to the increased cognitive load.

APPLICATION

The causal architecture of distributed brain regions inferred using DCM can help not only in the design of a balanced human-automation interface design but also in the proper use of automation in real-life situations.

Age-related differences in ventral striatal and default mode network function during reciprocated trust

Social relationships change across the lifespan as social networks narrow and motivational priorities shift to the present. Interestingly, aging is also associated with changes in executive function, including decision-making abilities, but it remains unclear how age-related changes in both domains interact to impact financial decisions involving other people. To study this problem, we recruited 50 human participants (Nyounger = 26, ages 18-34; Nolder = 24, ages 63-80) to play an economic trust game as the investor with three partners (friend, stranger, and computer) who played the role of investee. Investors underwent functional magnetic resonance imaging (fMRI) during the trust game while investees were seated outside of the scanner. Building on our previous work with younger adults showing both enhanced striatal responses and altered default-mode network (DMN) connectivity as a function of social closeness during reciprocated trust, we predicted that these relations would exhibit age-related differences. We found that striatal responses to reciprocated trust from friends relative to strangers and computers were blunted in older adults relative to younger adults, thus supporting our primary pre-registered hypothesis regarding social closeness. We also found that older adults exhibited enhanced DMN connectivity with the temporoparietal junction (TPJ) during reciprocated trust from friends compared to computers while younger adults exhibited the opposite pattern. Taken together, these results advance our understanding of age-related differences in sensitivity to social closeness in the context of trusting others.

Perceiving the facial trustworthiness: Facial age, emotional expression, and attractiveness

People can make trustworthiness judgements based on facial characteristics. However, the previous findings regarding whether facial age influences interpersonal trust are inconsistent. Using the trust game, the current study investigated the interactions of facial age with attractiveness and emotional expression in regard to trustworthiness judgements. In Experiments 1 and 2, younger participants were asked to invest in either younger or older faces that were shown for 2,000 and 33 ms, respectively. The results showed that people trust the faces of older people more than they do younger people. There was also an interaction between facial age and attractiveness. Participants invested more money in older faces than in younger faces only when they perceived the faces to be less attractive. However, the interaction between facial age and emotional expression was slightly inconsistent in the two experiments. Participants invested more money in older faces that were shown for 2,000 ms when they perceived the happy and sad emotions, but they invested more money in older faces that were shown for 33 ms when they perceived the happy emotion. These results reveal that people make trustworthiness judgements based on multiple facial cues when they view strangers of different ages.

Age and intranasal oxytocin effects on trust-related decisions after breach of trust: Behavioral and brain evidence

Age-related differences in cognition and socioemotional functions, and in associated brain regions, may reduce sensitivity to cues of untrustworthiness, with effects on trust-related decision making and trusting behavior. This study examined age-group differences in brain activity and behavior during a trust game. In this game, participants received "breach-of-trust" feedback after half of the trials. The feedback indicated that only 50% of the monetary investment into their fellow players had resulted in returns. The study also explored the effects of intranasal oxytocin on trust-related decisions in aging, based on suggestions of a modulatory role of oxytocin in response to negative social stimuli and perceptions of trust. Forty-seven younger and 46 older participants self-administered intranasal oxytocin or placebo, in a randomized, double-blind, between-subjects procedure, before they engaged in the trust game while undergoing functional magnetic resonance imaging (fMRI). Younger participants invested less into their game partners after breach-of-trust feedback, while older participants showed no significant difference in their investment after breach-of-trust feedback. Oxytocin did not modulate the behavioral effects. However, after breach-of-trust feedback, older participants in the oxytocin group showed less activity in the left superior temporal gyrus. In contrast, older participants in the placebo group showed more activity in left superior temporal gyrus after breach of trust. The findings may reflect reduced responsiveness to cues of untrustworthiness in older adults. Furthermore, the modulatory effect of oxytocin on left superior temporal gyrus activity among older adults supports the neuropeptide's age-differential role in neural processes in aging, including in the context of trust-related decision making. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Human aging alters social inference about others' changing intentions

Decoding others' intentions accurately in order to adapt one's own behavior is pivotal throughout life. In this study, we asked how younger and older adults deal with uncertainty in dynamic social environments. We used an advice-taking paradigm together with Bayesian modeling to characterize effects of aging on learning about others' time-varying intentions. We observed age differences when comparing learning on two levels of social uncertainty: the fidelity of the adviser and the volatility of intentions. Older adults expected the adviser to change his/her intentions more frequently (i.e., a higher volatility of the adviser). They also showed higher confidence (i.e., precision) in their volatility beliefs and were less willing to change their beliefs about volatility over the course of the experiment. This led them to update their predictions about the fidelity of the adviser more quickly. Potentially indicative of stereotype effects, we observed that older advisers were perceived as more volatile, but also more faithful than younger advisers. This offers new insights into adult age differences in response to social uncertainty.

Neural Signatures of Gender Differences in Interpersonal Trust

Trust plays a critical role in nearly every aspect of social life. Parental investment theory and social role theory predict that women trust less than men due to a higher sensitivity to risk and betrayal, while men trust more than women to maximize resources and to signal their willingness to lose something. However, the underlying neuropsychological underpinnings for this gender difference are still obscure. In this study, we used functional magnetic resonance imaging (fMRI) to investigate the neural signatures of gender differences in trust by simultaneously scanning 11 male and 11 female same-gender, fixed dyads who played a multi-round binary trust game with varying levels of payoff (low/moderate/high) as an indicator of social risk. Our results showed that men trusted more than women and payoff level moderated the effect of gender on trust. While men trusted the same at all payoff levels, women trusted less with higher payoff levels. This pattern was supported by our neuroimaging finding: men showed a higher activation in the left inferior frontal gyrus (ventrolateral prefrontal cortex) and right precuneus than women, indicating that men exert more effort to inhibit the information of payoff levels and to use self-referencing to infer the strategies of partners with the goal of maximizing profit. Furthermore, men showed equivalent activation in the subgenual anterior cingulate cortex across payoff levels, whereas women showed a decreased activation with increasing payoff level - indicating decreased group bonding with higher risk in women. In conclusion, our results imply that women are more sensitive to social risk while trusting, which has implications for financial interactions, interpersonal relationships, and social involvement.

Age differences in neural activity related to mentalizing during person perception

Mentalizing, or thinking about others' mental states, shapes social interactions. Older adults (OA) have reduced mentalizing capacities reflected by lower medial prefrontal cortex (mPFC) activation. The current study assessed if OA' lower mPFC activation reflects less spontaneous mentalizing during person perception. Younger adults (YA) and OA viewed ingroup White and outgroup Black and Asian faces and completed a mentalizing task during fMRI. Afterward, they completed a task in which they inferred mental states from faces. Using an mPFC region defined by the mentalizing task, OA had lower activity than YA during person perception. OA' mPFC activity toward faces positively related to their mentalizing outside the scanner. The extent of OA' lower mPFC activation during person perception may depend on their actual detection of mental states in faces. Further, YA', but not OA', mPFC activity distinguished between outgroups. OA' lower mentalizing-related mPFC activity may reduce their ability to individuate outgroup members.

Personality Factors' Impact on the Structural Integrity of Mentalizing Network in Old Age: A Combined PET-MRI Study

The mentalizing network (MN) treats social interactions based on our understanding of other people's intentions and includes the medial prefrontal cortex (mPFC), temporoparietal junction (TPJ), posterior cingulate cortex (PCC), precuneus (PC), and amygdala. Not all elders are equally affected by the aging-related decrease of mentalizing abilities. Personality has recently emerged as a strong determinant of functional connectivity in MN areas. However, its impact on volumetric changes across the MN in brain aging is still unknown. To address this issue, we explored the determinants of volume decrease in MN components including amyloid burden, personality, and APOE genotyping in a previously established cohort of 130 healthy elders with a mean follow-up of 54 months. Personality was assessed with the Neuroticism Extraversion Openness Personality Inventory-Revised. Regression models corrected for multiple comparisons were used to identify predictors of volume loss including time, age, sex, personality, amyloid load, presence of APOE epsilon 4 allele, and cognitive evolution. In cases with higher Agreeableness scores, there were lower volume losses in PCC, PC, and amygdala bilaterally. This was also the case for the right mPFC in elders displaying lower Agreeableness and Conscientiousness. In multiple regression models, the effect of Agreeableness was still observed in left PC and right amygdala and that of Conscientiousness was still observed in right mPFC volume loss (26.3% of variability, significant age and sex). Several Agreeableness (Modesty) and Conscientiousness (order, dutifulness, achievement striving, and self-discipline) facets were positively related to increased volume loss in cortical components of the MN. In conclusion, these data challenge the beneficial role of higher levels of Agreeableness and Conscientiousness in old age, showing that they are associated with an increased rate of volume loss within the MN.