Effects of False Statements on Visual Perception Hinge on Social Suggestibility

Verbal hints can bias perceptual decision-making, even when the information they provide is false. What makes individuals more or less susceptible to such influences, however, remains unclear. Here, we inquire whether suggestibility to social influence, a high-level trait measured by a standard suggestibility scale, could predict changes in perceptual judgments. We asked naive participants to indicate the dominant color in a series of stimuli after giving them a short, false verbal statement about which color would likely dominate. We found that this statement biased participants' perceptual judgments of the dominant color, as shown by a correlated shift of their discrimination performance, confidence judgments, and response times. Crucially, this effect was more pronounced in participants with higher levels of susceptibility to social influence. Together, these results indicate that social suggestibility can determine how much simple (albeit false) verbal hints influence perceptual judgments. Public Significance Statement At a time when fake news soars, understanding the role that simple verbal descriptions play in how we perceive the world around us is paramount. Extensive research has shown that perception is permeable to well-orchestrated manipulation. However, even simple and straightforward statements can bias individuals' expectations, altering their perception. Critically, here we show that this perceptual bias depends on individual susceptibility to social influence (i.e., a high-order trait reflecting the tendency to orient one's feelings and behaviors by the feelings and behaviors of others). Considering how, here, perception was biased by just a single false sentence, we argue that researchers, communicators, and policy makers should pay careful attention to the role that social suggestibility plays in how we build our perceptual judgments.