Brian Silston

Natural observations suggest that in safe environments, organisms avoid competition to maximize gain, while in hazardous environments the most effective survival strategy is to congregate with competition to reduce the likelihood of predatory attack. We probed the extent to which survival decisions in humans follow these patterns, and examined the factors that determined individual-level decision-making. In a virtual foraging task containing changing levels of competition in safe and hazardous patches with virtual predators, we demonstrate that human participants inversely select competition avoidant and risk diluting strategies depending on perceived patch value (PPV), a computation dependent on reward, threat, and competition. We formulate a mathematically grounded quantification of PPV in social foraging environments and show using multivariate fMRI analyses that PPV is encoded by mid-cingulate cortex (MCC) and ventromedial prefrontal cortices (vMPFC), regions that integrate acti...

When we face danger or stress, the presence of others can provide a powerful signal of safety and support. However, despite a large literature on group living benefits in animals, few studies have been conducted on how group size alters subjective emotional responses and threat perception in humans. We conducted 5 experiments (N = 3,652) to investigate whether the presence of others decreases fear in response to threat under a variety of conditions. In Studies 1, 2 and 3, we experimentally manipulated group size in hypothetical and real-world situations and found that fear responses decreased as group size increased. In Studies 4 and 5 we again used a combination of hypothetical and real-world decisions to test whether increased anxiety in response to a potential threat would lead participants to choose larger groups for themselves. Participants consistently chose larger groups when threat and anxiety were high. Overall, our findings show that group size provides a salient signal of protection and safety in humans. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

IntroductionIn response to collective life events, many people regulate their emotional states through social interactions to reduce cognitive tolls. During pandemics, physical distancing renders the social support strategy less viable, increasing mental health risks.ObjectivesThe current work aims to understand the range of emotions and strategies used in a population of Mental Health staff.MethodsWe conducted an anonymous survey on staff from OMH facilities (n=211) to assess the impact of Covid-19. The current survey captures a host of social, affective, and demographic variables. Accompanied by scales on emotions, emotion regulation, risk, and perception.ResultsWork, family, and health-concerns were the primary contributors to mood. The most common strategy was “situation-avoidance,” then “exercising.” When comparing depression scores against whether or not specific kinds of regulation strategies were utilized, only differences in the strategy of “emotion-suppression” and “author...

The social environment presents the human brain with the most complex information processing demands. The computations that the brain must perform occur in parallel, combine social and nonsocial cues, produce verbal and nonverbal signals and involve multiple cognitive systems, including memory, attention, emotion and learning. This occurs dynamically and at timescales ranging from milliseconds to years. Here, we propose that during social interactions, seven core operations interact to underwrite coherent social functioning; these operations accumulate evidence efficiently—from multiple modalities—when inferring what to do next. We deconstruct the social brain and outline the key components entailed for successful human–social interaction. These include (i) social perception; (ii) social inferences, such as mentalizing; (iii) social learning; (iv) social signaling through verbal and nonverbal cues; (v) social drives (e.g. how to increase one’s status); (vi) determining the social id...

Goal-directed behavior requires adaptive systems that respond to environmental demands. In the absence of threat (or presence of reward), individuals are free to explore a large number of behavioral trajectories, effectively interrogating the environment across many dimensions. This leads to flexible, relational memory encoding and retrieval. In the presence of imminent danger, motivation shifts to an imperative state characterized by a narrow focus of attention on threatening information. This impairs flexible, relational memory. Here, we test how these proposed motivational shifts (Murty & Adcock, 2017) affect behavioral flexibility and memory in an ecologically valid setting. Participants learned the structure of a maze-like environment and navigated to the location of everyday objects in both safe and threatening contexts. The latter contained a predator that could ‘capture’ participants, leading to electric shock. After learning, the path to some objects was unpredictably block...

The social environment presents the human brain with the most complex information processing demands. The computations that the brain must perform occur in parallel, combine social and nonsocial cues, produce verbal and nonverbal signals and involve multiple cognitive systems, including memory, attention, emotion and learning. This occurs dynamically and at timescales ranging from milliseconds to years. Here, we propose that during social interactions, seven core operations interact to underwrite coherent social functioning; these operations accumulate evidence efficiently—from multiple modalities—when inferring what to do next. We deconstruct the social brain and outline the key components entailed for successful human–social interaction. These include (i) social perception; (ii) social inferences, such as mentalizing; (iii) social learning; (iv) social signaling through verbal and nonverbal cues; (v) social drives (e.g. how to increase one’s status); (vi) determining the social id...

Primates have developed a unique set of complex drives for successful group living, yet theorists rarely contemplate their taxonomy and how such drives relate to affective dynamics fundamental for group success. Affective dynamics and drive fulfillment exert mutual influence on one another, ultimately collectively promoting or undermining survival. We first identify six core benefits of group living common among both humans and other animals, and from this foundation we propose three broad social drives that have evolved to preserve or enhance group living benefits: (i) Mutualism comprises cooperation, reciprocity, trust, and fairness; (ii) Affiliation comprises assimilation and belonging, whereby one aims to fit into the group through adherence to group norms and ideologies; (iii) Status-Seeking is represented by a drive to build one’s value in the group and acquire differential access to mates and other resources. We identify affective dynamics that facilitate each social drive: (...

In group foraging organisms, optimizing the conflicting demands of competitive food loss and safety is critical. We demonstrate that humans select competition avoidant and risk diluting strategies during foraging depending on socially adjusted value. We formulate a mathematically grounded quantification of socially adjusted value in foraging environments and show using multivariate fMRI analyses that socially adjusted value is encoded by mid-cingulate and ventromedial prefrontal cortices, regions that integrate value and action signals.

According to Hamilton’s Selfish Herd Theory, a crucial survival benefit of group living is that it provides a ‘risk dilution’ function against predation. Despite a large literature on group living benefits in animals, few studies have been conducted on how group size alters subjective fear or threat perception in humans, and on what factors drive preferences for being in groups when facing threats. We conducted seven experiments (N=3,838) to test (A) if the presence of others decreases perception of threat under a variety of conditions. In studies 1 to 3, we experimentally manipulated group size in hypothetical and real-world situations, to show that fear responses decreased as group size increased. In studies 4 to 7 we again used a combination of hypothetical, virtual and real-world decisions to test (B) how internal states (e.g. anxiety) and external factors (e.g. threat level, availability of help) affected participants’ preference for groups. Participants consistently chose larg...

We propose a Survival Optimization System (SOS) to account for the strategies that humans and other animals use to defend against recurring and novel threats. The SOS attempts to merge ecological models that define a repertoire of contextually relevant threat induced survival behaviors with contemporary approaches to human affective science. We first propose that the goal of the nervous system is to reduce surprise and optimize actions by (i) predicting the sensory landscape by simulating possible encounters with threat and selecting the appropriate pre-encounter action and (ii) prevention strategies in which the organism manufactures safe environments. When a potential threat is encountered the (iii) threat orienting system is engaged to determine whether the organism ignores the stimulus or switches into a process of (iv) threat assessment, where the organism monitors the stimulus, weighs the threat value, predicts the actions of the threat, searches for safety, and guides behavio...

During social interaction, the brain has the enormous task of interpreting signals that are fleeting, subtle, contextual, abstract, and often ambiguous. Despite the signal complexity, the human brain has evolved to be highly successful in the social landscape. Here, we propose that the human brain makes sense of noisy dynamic signals through accumulation, integration, and prediction, resulting in a coherent representation of the social world. We propose that successful social interaction is critically dependent on a core set of highly connected hubs that dynamically accumulate and integrate complex social information and, in doing so, facilitate social tuning during moment-to-moment social discourse. Successful interactions, therefore, require adaptive flexibility generated by neural circuits composed of highly integrated hubs that coordinate context appropriate responses. Adaptive properties of the neural substrate, including predictive and adaptive coding, and neural reuse, along with perceptual, inferential, and motivational inputs, provide the ingredients for pliable, hierarchical predictive models that guide our social interactions.

Financial incentives are commonly used as motivational tools to enhance performance. Decades of research have established that the neurotransmitter dopamine (DA) is the fuel that propels reward-motivated behavior, yet a new PET study questions whether dopamine is beneficial to performance, showing that tonic DA synthesis predicts performance decrements when incentives are high.