A simple verbal hint can alter a person’s visual perception, especially if they are highly suggestible

New psychology research shows just how easy it is to sway a person’s perceptual judgments, leading them to think they see something that is not there. According to the findings, a short verbal statement can alter a person’s visual perception, especially if they are more susceptible to social influence. The findings were published in the Journal of Experimental Psychology: Human Perception and Performance.

Social influence is a powerful phenomenon that can shape our perception of the world. For example, studies suggest that even a simple verbal statement can influence what we think we see in front of us by altering our sensory and perceptual mechanisms. Researchers Hernán Anlló (@AnlloHernan) and his colleagues note that the proliferation of fake news has made it even more important to understand how words can impact our perception.

The study authors sought to explore why some people are more susceptible to this type of social influence than others. The researchers speculated that the answer to this question has to do with social suggestibility — a higher-level trait that describes an inclination to adopt the feelings and behaviors of others.

“The subjects of understanding what the building blocks of our perception are, and what the role of prior information in the construction of perception is, are fascinating in their own right, and have become of crucial importance with the explosion of social media,” said Anlló, a senior postdoctoral researcher at Paris Sciences et Lettres University and founding member of the Intercultural Cognitive Network.

“Information is circulating with unprecedented speed, and it even finds its way into our social feeds against our will sometimes. It’s becoming increasingly difficult to observe events without having to go through some level of information on those events beforehand (e.g. buying a shirt, but not before reading its reviews online). What we are looking at in our research here is how much the information you receive is going to contribute to the construction of your perceptual reality, and fundamentally, what are the individual psychological features that condition the impact that that information will have in shaping what you see and think, whether you like it or not.”

“Of course, we are not talking about enormous effects that can completely distort the world around you (e.g., no amount of false/imprecise information can make you misperceive a small bird as a 3-ton truck),” Anlló explained, “but what our study shows is that, provided you are permeable enough to social influence (which we all are, the key here being how much), then false information can slightly shift your perception in whatever direction the information points.”

Anlló and his team conducted a lab experiment among a sample of 53 young adults between the ages of 18 and 23. The experiment involved a series of trials during which participants were shown a stimulus on a screen that was made up of 100 colored dots. Depending on the trial, each stimulus contained different proportions of two different colors (e.g., 40% blue dots and 60% yellow dots). The main task for participants was to indicate which color they believed was the dominant color and how confident they were with this decision.

Importantly, there were two different conditions depending on the statement participants were shown before each block of trials. During the bias condition, participants were shown a statement informing them that a certain color was twice as likely to be the dominant color. This hint was correct only half of the time. During the control condition, participants read an unbiased statement expressing that each color had a 50/50 chance of being the dominant color.

Following the experiment, the participants completed a measure of social suggestibility and were split into high, medium, and low suggestibility groups based on their responses.

After analyzing the data, the researchers found that the biased statements influenced the participants’ perceptions so they shifted toward perceiving the color that had been hinted at as the dominant color. In line with the study authors’ hypothesis, this shift was only seen among those with medium or high levels of social suggestibility.

The findings highlight “that perception is a complex construction, and information is never an innocent bystander in this process,” Anlló told PsyPost. “Always be informed, but make sure that your sources are of high quality, and trustworthy. Importantly, when I say high-quality I do not mean a source that you may trust because of emotional reasons or social links, but rather by the accuracy of the information they provide and the soundness of the evidence.”

“Indeed, our experiment shows that your level of suggestibility to your social environment (how much you dress like your friends, or feel influenced by their taste in music) will also predict your permeability to perceptual changes triggered by false information. This, much like many other cognitive biases, is part of the human experience, and essentially nothing to worry about. Being susceptible to your social environment is actually a great thing that makes us humans thrive as a species, we just need to be aware of it and try our best to limit our exposure to bad information.”

Interestingly, participants’ confidence ratings and response times also shifted with the bias condition. Participants who were medium or high in suggestibility were more confident in their decisions after reading the biased statements compared to the control statements, while those in the low suggestibility group were not.

On the other hand, participants with low suggestibility responded more slowly to the trials in the bias condition than in the control condition. The authors said this unexpected finding may suggest that participants who were low in suggestibility were thrown off by the false statements in the bias condition and experienced a kind of cognitive conflict. This idea is supported by the fact that these participants’ choices were unaffected by the biased information. “Low-suggestibility participants resisted the cue, whereas high-suggestibility participants incorporated the cue as additional (and nonconflicting) information,” the authors wrote.

Anlló and his colleagues say these findings are reminiscent of hypnosis and placebo effects, which have revealed that people can be manipulated to perceive things that are not there through the power of suggestion. However, the results are unique in that participants’ perceptions were influenced without the elaborate mental routines that often accompany hypnosis. “In our work, we show that false simple verbal hints and instructions suffice to trigger shifts in perceptual judgments,” the authors explain, “despite the absence of associative learning schemes or mental exercises.”

The researchers said that this topic warrants future research.

“There is a lot of healthy debate around whether this informational impact is purely perceptual in nature, or rather if it triggers some set of conscious and/or unconscious cognitive strategies,” Anlló said. “Simply put, if I hear a red ball is actually green, will I truly see it as being a bit greener, or will I convince myself that it is greener and act accordingly despite my actual perception of the ball not changing?”

“I would argue, given our results, that there are grounds to think that the changes induced by false information in our experiment were perceptual, but I do understand it is not possible to uphold that argument conclusively at the present time and remain open to the alternative. What’s important here is that neither of these alternatives change the fact that the administered false information had an impact in terms of behavior (participants did act swayed by the false instruction) and internal judgment (participants’ ‘feeling’ and confidence also followed the false information).”

“Further, the main goal of our study was not to understand whether false information would alter perception, but rather if its effects depended on suggestibility to social suggestion (how much you dress like your friends, or feel influenced by their taste in music), which is a very high-level psychological feature that one would instinctively imagine to have little to do with a low level perceptual task as the one we used,” Anlló explained.

“Further research should be conducted to try to understand what other social features that we may typically ignore when understanding cognitive perception may actually be playing a strong role in the process, and to what extent their impact may be purely perceptual, strategic, or a combination of both.”

The study, “Effects of false statements on visual perception hinge on social suggestibility”, was authored by Hernán Anlló, Katsumi Watanabe, Jérôme Sackur, and Vincent de Gardelle.