Humans make many important decisions in social environments. Social judgements of interaction partners based on the cues they send likely influence those decisions, by shaping expectations about the utility or subjective desirability of interacting with those partners. Here I examine how subtle differences in social utility judgements shape the influence social cues have onthe decision‐making process, in a series of three broad questions. The first of these relates to the intrinsic value of specific social cues. Anecdotally, cues such as smiles carry value as social rewards. Using a novel application of expected utility theory in an economic game, I show that relative to polite smiles, participants value genuine smiles to the extent that they are willing to forgo the chance to win money for the chance to see these social rewards. This suggests that genuine smiles have value as social cues and increase the utility of the interaction partners who display them.
In social interaction, people receive many different types of social cues. These include, static appearance‐based cues such as facial trustworthiness, dynamic expressions such as smiles, and the social decisions an interaction partner makes. These cues sometimes conflict–for example, when an untrustworthy face smiles genuinely. My second question addresses how these cues interact during social decision‐making. I investigated how conflicting cues modulate social utility in an investor‐trustee game. Surprisingly, unfavourable appearance‐based judgements biased investment behaviour long after people had learned the value of a face based on behaviour. Interestingly, a smile present at the time of feedbackeliminated this bias. This suggests when more stable cues (appearance and behaviour) conflict, dynamic cues (expressions) are powerful modulators of social utility.
My final question considered one mechanism for understanding how social cues shape decision‐making. Specifically, social cues may bias the allocation of attention during social interactions, thereby shaping the social information people acquire. I examined how appearance‐ and behaviour‐based judgements altered the allocation of attention to social stimuli. Strong appearance‐based judgements (positive and negative) enhanced stimulus recognition but only positive behaviour‐based judgements altered involuntary allocation of attention to stimuli. This suggests that behaviour‐based social utility judgements alter pre‐attentive processing, and consequently bias attention distribution.Taken together, these findings suggest that appearance, facial expression and behaviour cues all contribute to social utility, and this utility guides decision‐making in social environments.