Social influences on reality-monitoring decisions.

A modified Asch (1951) conformity paradigm was used to study the impact of social influence on reality-monitoring decisions about new items. Subjects studied pictures of some objects and imagined others. In a later test phase, they judged whether items had been perceived in the study phase, had been imagined, or were new. Critically, for some items, the subjects were informed of a confederate's response before rendering a judgment. Although the confederate was always correct when they responded to old items, for new items, the confederate responded perceived, imagined, or new, or did not respond (baseline). In two experiments, we show that memory for new items was influenced by an erroneous response of the confederate. Social conformity was reduced by undermining the credibility of the confederate (Experiments 1A and 1B), and the confederate's influence was evident even after there was only a 20-min delay between study and test (Experiment 2), when the subjects were 87% accurate on new baseline items. These experiments reveal the power of social influence on reality-monitoring accuracy and confidence.