Virtually simulated social pressure influences early visual processing more in low compared to high autonomous participants

Social influence and social identity: A diffusion model analysis

Building on the seminal studies of Solomon Asch and Muzafer Sherif, recent research has advanced our understanding of the mechanisms underlying social influence by applying a diffusion model analysis. Here, we combined the social identity approach to social influence with a diffusion model analysis to unravel the mechanisms underlying social influence. In particular, we aimed to disentangle whether the difference between in-group and out-group influence on perceptual decision-making is driven by a judgmental bias (i.e., changes in decision criteria) or a perceptual bias (i.e., changes in the uptake of sensory information). Preregistered analyses indicated that in-groups exerted stronger social influence than out-groups because in-groups induced a stronger perceptual bias than out-groups. This finding is in line with the single process assumption of the social identity approach because it implicates that the single process driving social influence (i.e., self-categorisation) translates into a change in a single subprocess of decision-making (i.e., biased information uptake). In conclusion, our results highlight that our theoretical understanding of social influence can be expanded by integrating the social identity approach with a diffusion model analysis.

Social norms shape visual appearance: Taking a closer look at the link between social norm learning and perceptual decision-making

One of the most fundamental questions in social psychology is whether norms can change individuals' minds by shaping the visual appearance of stimuli. This question was first raised by Muzafer Sherif (1935). Drawing on the extended social reinforcement account (Germar and Mojzisch, 2019), we aimed to provide a rigorous test of the hypothesis that norm learning leads to a persistent perceptual bias and, hence, to a change in the visual appearance of stimuli. From a methodological perspective, we used both a diffusion model approach and the method of adjustment, a well-established technique from psychophysics and vision research. The results of Experiments 1-3 show that norm effects on perceptual decision-making are robustly replicable, and are due to genuine social influence, that is, they cannot be explained by non-social priming, contingency learning effects (Experiments 1 and 2) or anchoring effects (Experiment 3). Most importantly, by using a psychophysical approach, Experiment 4 shows, for the first time, that social norm learning alters individuals' point of subjective equality and, hence, the visual appearance of stimuli.

Measuring the mental

Many philosophers have argued that the subjective character of conscious experience results in a fundamental deficit of third-person (henceforth: extrospective) access to first-person experience. By comparing extrospective measurement techniques with measurement techniques in the natural sciences, we will argue that extrospective methods suffer from no such deficit. After a rejection of some principled objections against extrospective methods, a historical comparison with the development of measurement techniques in the natural sciences will show that extrospective measuring methods are still in an early stage of development. However, they can be significantly improved by way of a bootstrapping strategy, similar to that which has proven successful in the development of physical measurement techniques. One reason to expect such improvement is the availability of multiple sources of evidence, which should allow for substantial advances in extrospective measurement techniques. Finally, we will discuss new developments in pain measurement in order to show that the bootstrapping strategy is already bearing fruit.

Developmental trajectory of social influence integration into perceptual decisions in children

The opinions of others have a profound influence on decision making in adults. The impact of social influence appears to change during childhood, but the underlying mechanisms and their development remain unclear. We tested 125 neurotypical children between the ages of 6 and 14 years on a perceptual decision task about 3D-motion figures under informational social influence. In these children, a systematic bias in favor of the response of another person emerged at around 12 years of age, regardless of whether the other person was an age-matched peer or an adult. Drift diffusion modeling indicated that this social influence effect in neurotypical children was due to changes in the integration of sensory information, rather than solely a change in decision behavior. When we tested a smaller cohort of 30 age- and IQ-matched autistic children on the same task, we found some early decision bias to social influence, but no evidence for the development of systematic integration of social influence into sensory processing for any age group. Our results suggest that by the early teens, typical neurodevelopment allows social influence to systematically bias perceptual processes in a visual task previously linked to the dorsal visual stream. That the same bias did not appear to emerge in autistic adolescents in this study may explain some of their difficulties in social interactions.

Social conformity is due to biased stimulus processing: electrophysiological and diffusion analyses

Hundreds of studies have found that humans' decisions are strongly influenced by the opinions of others, even when making simple perceptual decisions. In this study, we aimed to clarify whether this effect can be explained by social influence biasing (early) perceptual processes. We employed stimulus evoked potentials, lateralized readiness potentials (LRPs) and a diffusion model analysis of reaction time data to uncover the neurocognitive processes underlying social conformity in perceptual decision-making. The diffusion model analysis showed that social conformity was due to a biased uptake of stimulus information and accompanied by more careful stimulus processing. As indicated by larger N1-amplitudes, social influence increased early attentional resources for stimulus identification and discrimination. Furthermore, LRP analyses revealed that stimulus processing was biased even in cases of non-conformity. In conclusion, our results suggest that the opinion of others can cause individuals to selectively process stimulus information supporting this opinion, thereby inducing social conformity. This effect is present even when individuals do not blindly follow the majority but rather carefully process stimulus information.

The neuroscience of social conformity: implications for fundamental and applied research

The development of closer ties between researchers and practitioners in the domain of behavior and behavioral change offers useful opportunities for better informing public policy campaigns via a deeper understanding of the psychological processes that operate in real-world decision-making. Here, we focus on the domain of social conformity, and suggest that the recent emergence of laboratory work using neuroscientific techniques to probe the brain basis of social influence can prove a useful source of data to better inform models of conformity. In particular, we argue that this work can have an important role to play in better understanding the specific mechanisms at work in social conformity, in both validating and extending current psychological theories of this process, and in assessing how behavioral change can take place as a result of exposure to the judgments of others. We conclude by outlining some promising future directions in this domain, and indicating how this research could potentially be usefully applied to policy issues.

Social proof in the human brain: Electrophysiological signatures of agreement and disagreement with the majority

Perceiving one's deviance from the majority usually instigates conformal adjustments of one's own behavior to that of the group. Using ERPs, we investigated the mechanisms by which agreeing and disagreeing with the majority are differentially represented in the human brain and affect subsequent cognitive processing. Replicating previous findings obtained in a slightly different paradigm, we found that learning about one's disagreement with the majority, as compared to learning about one's agreement with the majority, elicited a mediofrontal feedback negativity. Moreover, an enhanced posterior late positive complex was observed during the processing of agreement as compared to disagreement. Finally, when the to-be-judged faces were viewed for a second time, a stronger posterior P2 was observed for faces on whose judgment one had previously agreed with the majority than for those on which one had disagreed. We thus demonstrate that the brain places particular emphasis on the encoding of the rewarding experience of finding strong social proof for one's judgments. Likewise, having experienced agreement on the judgment of a certain item affects even the later reanalysis of this very item, as previous agreement increases early attention, as reflected in the P2. These findings corroborate and extend previous results and theories on the neurocognitive principles of social influence.