Social evaluative stress disrupts action learning

How does social evaluation modulate behavioral and neural mechanisms underlying value-based decision-making? Social evaluation is likely to play a particularly important role when the potential for embarrassing errors is substantial, and so we investigated it using an orthogonalized reward/punishment-based Go/NoGo task in which untoward Pavlovian influences favoring Go in a reward scenario and NoGo in a punishment scenario are known to disturb required instrumental actions. Thirty participants completed this task in three social contexts: in isolation, with the passive presence, and under the active evaluation, of another person. We found that the experience of being socially evaluated selectively impaired learning of Go responses, while NoGo learning was unimpaired. Phasic pupillary response to the required action was attenuated under the evaluation, over and above the mere presence of the other person, suggesting altered noradrenergic activity emanating from evaluation stress. Social evaluation also shifted Positivity bias from near-neutral levels to a significantly negative bias, pointing to more conservative decision-making strategies when under social judgment. These findings indicate that social evaluative stress specifically disrupts action generation, aligning with theories positing that stress promotes passive or habitual responses.