Choice History Biases in Dyadic Decision-Making

Abstract How do we interact with our environment and make decisions about the world around us? Empirical research using psychophysical tasks has demonstrated that our perceptual decisions are influenced by past choices, a phenomenon known as the “choice history bias” effect. This decision-making process suggests that the brain adapts to environmental uncertainties based on history. However, the use of single-subject experiment task design is prevalent across the work on choice history bias, thus limiting the implications of the empirical evidence to individual decisions. Here, we explore the choice history bias effect using a dual-participant approach, where dyads perform a shared perceptual decision-making task. We first consider two extreme hypotheses: the participant either treats his/her partner’s decision as his/her own or simply ignores the partner’s decision. We then use a statistical modeling approach to fit generalized linear models to the choice data in a series of steps. Our best-fitting model suggests the participant has a choice repetition bias that spans several trials in the past, compatible with previous single-participant studies. Yet, there is also a dyadic influence on decision-making where both the participant’s own and partner’s last responses indicated a choice alternation bias. The results reject the hypothesis that the participant ignores the partner’s decision, in line with the idea that perceptual decision-making is not solely an individualistic decision process, though the partners’ decisions are treated differently from their own decisions.