Shihui Han

Empathy for the social suffering of friends and strangers recruits distinct patterns of brain activation

Humans observe various peoples social suffering throughout their lives, but it is unknown whether the same brain mechanisms respond to people we are close to and strangers social suffering. To address this question, we had participants complete functional magnetic resonance imaging (fMRI) while observing a friend and stranger experience social exclusion. Observing a friends exclusion activated affective pain regions associated with the direct (i.e. firsthand) experience of exclusion [dorsal anterior cingulate cortex (dACC) and insula], and this activation correlated with self-reported self-other overlap with the friend. Alternatively, observing a strangers exclusion activated regions associated with thinking about the traits, mental states and intentions of others [mentalizing; dorsal medial prefrontal cortex (DMPFC), precuneus, and temporal pole]. Comparing activation from observing friends vs strangers exclusion showed increased activation in brain regions associated with the firsthand experience of exclusion (dACC and anterior insula) and with thinking about the self [medial prefrontal cortex (MPFC)]. Finally, functional connectivity analyses demonstrated that MPFC and affective pain regions activated in concert during empathy for friends, but not strangers. These results suggest empathy for friends social suffering relies on emotion sharing and self-processing mechanisms, whereas empathy for strangers social suffering may rely more heavily on mentalizing systems.

Neural representations of close others in collectivistic brains

Our recent work showed that close relationships result in shared cognitive and neural representations of the self and ones mother in collectivistic individuals (Zhu et al., 2007, Neuroimage, 34, 1310-7). However, it remains unknown whether close others, such as mother, father and best friend, are differentially represented in collectivistic brains. Here, using functional magnetic resonance imaging and a trait judgment task, we showed evidence that, while trait judgments of the self and mother generated comparable activity in the medial prefrontal cortex (MPFC) and anterior cingulate (ACC) of Chinese adults, trait judgments of mother induced greater MPFC/ACC activity than trait judgments of father and best friend. Our results suggest that, while neural representations of the self and mother overlapped in the MPFC/ACC, close others such as mother, father and best friend are unequally represented in the MPFC/ACC of collectivistic brains.

Sociocultural patterning of neural activity during self-reflection

Western cultures encourage self-construals independent of social contexts, whereas East Asian cultures foster interdependent self-construals that rely on how others perceive the self. How are culturally specific self-construals mediated by the human brain? Using functional magnetic resonance imaging, we monitored neural responses from adults in East Asian (Chinese) and Western (Danish) cultural contexts during judgments of social, mental and physical attributes of themselves and public figures to assess cultural influences on self-referential processing of personal attributes in different dimensions. We found that judgments of self vs a public figure elicited greater activation in the medial prefrontal cortex (mPFC) in Danish than in Chinese participants regardless of attribute dimensions for judgments. However, self-judgments of social attributes induced greater activity in the temporoparietal junction (TPJ) in Chinese than in Danish participants. Moreover, the group difference in TPJ activity was mediated by a measure of a cultural value (i.e. interdependence of self-construal). Our findings suggest that individuals in different sociocultural contexts may learn and/or adopt distinct strategies for self-reflection by changing the weight of the mPFC and TPJ in the social brain network.

5-HTTLPR Polymorphism Modulates Neural Mechanisms of Negative Self-Reflection

Cognitive distortion in depression is characterized by enhanced negative thoughts about both environment and oneself. Carriers of a risk allele for depression, that is, the short (s) allele of the serotonin transporter promoter polymorphism (5-HTTLPR), exhibit amygdala hyperresponsiveness to negative environmental stimuli relative to homozygous long variant (l/l). However, the neural correlates of negative self-schema in s allele carriers remain unknown. Using functional MRI, we scanned individuals with s/s or l/l genotype of the 5-HTTLPR during reflection on their own personality traits or a friends personality traits. We found that relative to l/l carriers, s/s carriers showed stronger distressed feelings and greater activity in the dorsal anterior cingulate (dACC)/dorsal medial prefrontal cortex (dmPFC) and the right anterior insula (AI) during negative self-reflection. The 5-HTTLPR effect on the distressed feelings was mediated by the AI/inferior frontal (IF) activity during negative self-reflection. The dACC/dmPFC activity explained 20% of the variation in harm-avoidance tendency in s/s but not l/l carriers. The genotype effects on distress and brain activity were not observed during reflection on a friends negative traits. Our findings reveal that 5-HTTLPR polymorphism modulates distressed feelings and brain activities associated with negative self-schema and suggest a potential neurogenetic susceptibility mechanism for depression.

How culture gets embrained: Cultural differences in event-related potentials of social norm violations

Significance Despite the fact that social norms are a fundamental aspect of human nature, there has been little research on how social norm violations are detected at the neurobiological level. Combining a new social norm violation paradigm with cross-cultural electroencephalography, we show consistent negative deflection of event-related potential around 400 ms (N400) over the central and parietal regions for both Americans and Chinese in detecting norm violations. However, the N400 at the frontal and temporal regions was evident only among Chinese, illustrating culture-specific neural substrates underlying detecting norm violations. Moreover, the frontal N400 was associated with greater cultural superiority and self-control, as well as lower creativity. The findings shed new light on the neurobiology of the detection of social norm violations. Humans are unique among all species in their ability to develop and enforce social norms, but there is wide variation in the strength of social norms across human societies. Despite this fundamental aspect of human nature, there has been surprisingly little research on how social norm violations are detected at the neurobiological level. Building on the emerging field of cultural neuroscience, we combine noninvasive electroencephalography (EEG) with a new social norm violation paradigm to examine the neural mechanisms underlying the detection of norm violations and how they vary across cultures. EEG recordings from Chinese and US participants (n = 50) showed consistent negative deflection of event-related potential around 400 ms (N400) over the central and parietal regions that served as a culture-general neural marker of detecting norm violations. The N400 at the frontal and temporal regions, however, was only observed among Chinese but not US participants, illustrating culture-specific neural substrates of the detection of norm violations. Further, the frontal N400 predicted a variety of behavioral and attitudinal measurements related to the strength of social norms that have been found at the national and state levels, including higher culture superiority and self-control but lower creativity. There were no cultural differences in the N400 induced by semantic violation, suggesting a unique cultural influence on social norm violation detection. In all, these findings provided the first evidence, to our knowledge, for the neurobiological foundations of social norm violation detection and its variation across cultures.

Oxytocin and Social Adaptation: Insights from Neuroimaging Studies of Healthy and Clinical Populations

Adaptation to the social environment is critical for human survival. The neuropeptide oxytocin (OT), implicated in social cognition and emotions pivotal to sociality and well-being, is a promising pharmacological target for social and emotional dysfunction. We suggest here that the multifaceted role of OT in socio-affective processes improves the capability for social adaptation. We review OT effects on socio-affective processes, with a focus on OT-neuroimaging studies, to elucidate neuropsychological mechanisms through which OT promotes social adaptation. We also review OT-neuroimaging studies of individuals with social deficits and suggest that OT ameliorates impaired social adaptation by normalizing hyper- or hypo-brain activity. The social adaption model (SAM) provides an integrative understanding of discrepant OT effects and the modulations of OT action by personal milieu and context.

A Culture–Behavior–Brain Loop Model of Human Development

Increasing evidence suggests that cultural influences on brain activity are associated with multiple cognitive and affective processes. These findings prompt an integrative framework to account for dynamic interactions between culture, behavior, and the brain. We put forward a culture-behavior-brain (CBB) loop model of human development that proposes that culture shapes the brain by contextualizing behavior, and the brain fits and modifies culture via behavioral influences. Genes provide a fundamental basis for, and interact with, the CBB loop at both individual and population levels. The CBB loop model advances our understanding of the dynamic relationships between culture, behavior, and the brain, which are crucial for human phylogeny and ontogeny. Future brain changes due to cultural influences are discussed based on the CBB loop model.

Equality bias impairs collective decision-making across cultures

Significance When making decisions together, we tend to give everyone an equal chance to voice their opinion. To make the best decisions, however, each opinion must be scaled according to its reliability. Using behavioral experiments and computational modelling, we tested (in Denmark, Iran, and China) the extent to which people follow this latter, normative strategy. We found that people show a strong equality bias: they weight each other’s opinion equally regardless of differences in their reliability, even when this strategy was at odds with explicit feedback or monetary incentives. We tend to think that everyone deserves an equal say in a debate. This seemingly innocuous assumption can be damaging when we make decisions together as part of a group. To make optimal decisions, group members should weight their differing opinions according to how competent they are relative to one another; whenever they differ in competence, an equal weighting is suboptimal. Here, we asked how people deal with individual differences in competence in the context of a collective perceptual decision-making task. We developed a metric for estimating how participants weight their partner’s opinion relative to their own and compared this weighting to an optimal benchmark. Replicated across three countries (Denmark, Iran, and China), we show that participants assigned nearly equal weights to each other’s opinions regardless of true differences in their competence—even when informed by explicit feedback about their competence gap or under monetary incentives to maximize collective accuracy. This equality bias, whereby people behave as if they are as good or as bad as their partner, is particularly costly for a group when a competence gap separates its members.

Self-construal priming modulates pain perception: Event- related potential evidence

We investigated whether and how temporary shifts in self-construals modulate neural correlates of pain perception. Event-related potentials (ERPs) to painful and non-painful electrical stimulations were recorded from adults after being primed with independent and interdependent self-construals. Electrical stimulations to the left hand elicited two negative components (N60 and N130) over the frontal /central regions and two positive components (P90 and P300) over the central/parietal regions with larger amplitudes over the right rather than the left hemispheres. Painful vs. non-painful stimulations enlarged P90, N130, and P300 amplitudes. Independent vs. interdependent self-construal priming induced larger N130 amplitudes to painful stimulations but did not affect the N130 amplitudes to non-painful stimulations. The self-construal priming effect on the P300 amplitudes to painful stimulation positively correlated with self-reported interdependence. Our ERP results suggest that temporary shifts in self-construals affect pain perception by modulating the neural activities engaged in early somatosensory and late evaluation processing of physical pain.

Challenging emotional prejudice by changing self-concept: priming independent self-construal reduces racial in-group bias in neural responses to other’s pain

Humans show stronger empathy for in-group compared with out-group members suffering and help in-group members more than out-group members. Moreover, the in-group bias in empathy and parochial altruism tend to be more salient in collectivistic than individualistic cultures. This work tested the hypothesis that modifying self-construals, which differentiate between collectivistic and individualistic cultural orientations, affects in-group bias in empathy for perceived own-race vs other-race pain. By scanning adults using functional magnetic resonance imaging, we found stronger neural activities in the mid-cingulate, left insula and supplementary motor area (SMA) in response to racial in-group compared with out-group members pain after participants had been primed with interdependent self-construals. However, the racial in-group bias in neural responses to others pain in the left SMA, mid-cingulate cortex and insula was significantly reduced by priming independent self-construals. Our findings suggest that shifting an individuals self-construal leads to changes of his/her racial in-group bias in neural responses to others suffering.