Naturalistic generative narratives reveal effects of social characteristics on decision-making.

Introduction: The social characteristics of others can powerfully influence our decisions. They can also be broadly impacted by the social context in which these choices are made, making the effects of these characteristics on decision-making especially challenging to understand.

Methods: Here, we developed a Generative Narrative Survey that provided participants with naturalistic scenarios that richly varied in social context and theme but that also systematically varied the characteristics of the social agents involved, followed by a question.

A stare like yours: Naturalistic social gaze interactions reveal robust neuronal representations.

In this issue of Neuron, Dal Monte, Fan, and colleagues (Dal Monte et al., 2022) show that rhesus monkeys have a widely distributed and robust neuronal representation of social gaze: looking at others and where others are looking.

Frontal neurons driving competitive behaviour and ecology of social groups.

Competitive interactions have a vital role in the ecology of most animal species and powerfully influence the behaviour of groups. To succeed, individuals must exert effort based on not only the resources available but also the social rank and behaviour of other group members. The single-cellular mechanisms that precisely drive competitive interactions or the behaviour of social groups, however, remain poorly understood.

Social agent identity cells in the prefrontal cortex of interacting groups of primates.

The ability to interact effectively within social groups is essential to primate and human behavior. Yet understanding the neural processes that underlie the interactive behavior of groups or by which neurons solve the basic problem of coding for multiple agents has remained a challenge. By tracking the interindividual dynamics of groups of three interacting rhesus macaques, we discover detailed representations of the groups’ behavior by neurons in the dorsomedial prefrontal cortex, reflecting not only the other agents’ identities but also their specific interactions, social context, actions, and outcomes.

Neuronal Circuits for Social Decision-Making and Their Clinical Implications.

Social living facilitates individual access to rewards, cognitive resources, and objects that would not be otherwise accessible. There are, however, some drawbacks to social living, particularly when competing for scarce resources. Furthermore, variability in our ability to make social decisions can be associated with neuropsychiatric disorders.

Nonhuman Primates Satisfy Utility Maximization in Compliance with the Continuity Axiom of Expected Utility Theory.

Expected Utility Theory (EUT), the first axiomatic theory of risky choice, describes choices as a utility maximization process: decision makers assign a subjective value (utility) to each choice option and choose the one with the highest utility. The continuity axiom, central to Expected Utility Theory and its modifications, is a necessary and sufficient condition for the definition of numerical utilities. The axiom requires decision makers to be indifferent between a gamble and a specific probabilistic combination of a more preferred and a less preferred gamble.

Single-neuronal predictions of others' beliefs in humans.

Human social behaviour crucially depends on our ability to reason about others. This capacity for theory of mind has a vital role in social cognition because it enables us not only to form a detailed understanding of the hidden thoughts and beliefs of other individuals but also to understand that they may differ from our own. Although a number of areas in the human brain have been linked to social reasoning and its disruption across a variety of psychosocial disorders, the basic cellular mechanisms that underlie human theory of mind remain undefined.

Monkeys Show Theory of Mind.

Hayashi et al. (2020) provide evidence that Japanese macaques show theory of mind abilities in an anticipatory-looking variant of the canonical false belief task. This study paves the way to investigate the neuronal basis of social cognition in non-human primates.

Primate Amygdala Neurons Simulate Decision Processes of Social Partners.

By observing their social partners, primates learn about reward values of objects. Here, we show that monkeys' amygdala neurons derive object values from observation and use these values to simulate a partner monkey's decision process. While monkeys alternated making reward-based choices, amygdala neurons encoded object-specific values learned from observation.

Performance error-related activity in monkey striatum during social interactions.

Monitoring our performance is fundamental to motor control while monitoring other's performance is fundamental to social coordination. The striatum is hypothesized to play a role in action selection, action initiation, and action parsing, but we know little of its role in performance monitoring. Furthermore, the striatum contains neurons that respond to own and other's actions.

A neuronal reward inequity signal in primate striatum.

Primates are social animals, and their survival depends on social interactions with others. Especially important for social interactions and welfare is the observation of rewards obtained by other individuals and the comparison with own reward. The fundamental social decision variable for the comparison process is reward inequity, defined by an asymmetric reward distribution among individuals.

The role of the striatum in social behavior.

Where and how does the brain code reward during social behavior? Almost all elements of the brain's reward circuit are modulated during social behavior. The striatum in particular is activated by rewards in social situations. However, its role in social behavior is still poorly understood.

Activity of striatal neurons reflects social action and own reward.

Social interactions provide agents with the opportunity to earn higher benefits than when acting alone and contribute to evolutionary stable strategies. A basic requirement for engaging in beneficial social interactions is to recognize the actor whose movement results in reward. Despite the recent interest in the neural basis of social interactions, the neurophysiological mechanisms identifying the actor in social reward situations are unknown.