Social context influences social decisions and outcome processing. In the present study a team of researchers from the University of Münster and the Biopsychology in Bochum investigated social context-dependent modulation of behavior and feedback. Adult participants completed an ultimatum game under social observation or not and EEG was recorded. Overall, fewer unfair than fair offers were accepted. Observation decreased acceptance rates for unfair offers. The feedback-locked feedback-related negativity (FRN) was modulated by observation and fairness, with stronger differential coding of unfair/fair under observation. This effect was strongly correlated with individual levels of social anxiety, with higher levels associated with stronger differential fairness coding in the FRN under observation. Behavioral findings support negative reciprocity in the UG, suggesting that social norms overwrite explicit task instructions even in the absence of social interaction. Observation enhances this effect.

Peterburs, J., Voegler, R., Liepelt, R., Schulze, A., Wilhelm, S., Ocklenburg, S., Straube, T. (2017). Processing of fair and unfair offers in the ultimatum game under social observation. Scientific Reports, 7. doi:10.1038/srep44062