Eryn J. Newman

On the (non)persuasive power of a brain image

The persuasive power of brain images has captivated scholars in many disciplines. Like others, we too were intrigued by the finding that a brain image makes accompanying information more credible (McCabe & Castel in Cognition 107:343-352, 2008). But when our attempts to build on this effect failed, we instead ran a series of systematic replications of the original study—comprising 10 experiments and nearly 2,000 subjects. When we combined the original data with ours in a meta-analysis, we arrived at a more precise estimate of the effect, determining that a brain image exerted little to no influence. The persistent meme of the influential brain image should be viewed with a critical eye.

Making the truth stick & the myths fade: Lessons from cognitive psychology

Summary: Erroneous beliefs are difficult to correct. Worse, popular correction strategies, such as the myth-versus-fact article format, may backfire because they subtly reinforce the myths through repetition and further increase the spread and acceptance of misinformation. Here we identify five key criteria people employ as they evaluate the truth of a statement: They assess general acceptance by others, gauge the amount of supporting evidence, determine its compatibility with their beliefs, assess the general coherence of the statement, and judge the credibility of the source of the information. In assessing these five criteria, people can actively seek additional information (an effortful analytic strategy) or attend to the subjective experience of easy mental processing—what psychologists call fluent processing—and simply draw conclusions on the basis of what feels right (a less effortful intuitive strategy). Throughout this truth-evaluation effort, fluent processing can facilitate acceptance of the statement: When thoughts flow smoothly, people nod along. Unfortunately, many correction strategies inadvertently make the false information more easily acceptable by, for example, repeating it or illustrating it with anecdotes and pictures. This, ironically, increases the likelihood that the false information the communicator wanted to debunk will be believed later. A more promising correction strategy is to focus on making the true information as easy to process as possible. We review recent research and offer recommendations for more effective presentation and correction strategies.

Lay understanding of forensic statistics: Evaluation of random match probabilities, likelihood ratios, and verbal equivalents.

Forensic scientists have come under increasing pressure to quantify the strength of their evidence, but it is not clear which of several possible formats for presenting quantitative conclusions will be easiest for lay people, such as jurors, to understand. This experiment examined the way that people recruited from Amazons Mechanical Turk (n = 541) responded to 2 types of forensic evidence--a DNA comparison and a shoeprint comparison--when an expert explained the strength of this evidence 3 different ways: using random match probabilities (RMPs), likelihood ratios (LRs), or verbal equivalents of likelihood ratios (VEs). We found that verdicts were sensitive to the strength of DNA evidence regardless of how the expert explained it, but verdicts were sensitive to the strength of shoeprint evidence only when the expert used RMPs. The weight given to DNA evidence was consistent with the predictions of a Bayesian network model that incorporated the perceived risk of a false match from 3 causes (coincidence, a laboratory error, and a frame-up), but shoeprint evidence was undervalued relative to the same Bayesian model. Fallacious interpretations of the experts testimony (consistent with the source probability error and the defense attorneys fallacy) were common and were associated with the weight given to the evidence and verdicts. The findings indicate that perceptions of forensic science evidence are shaped by prior beliefs and expectations as well as expert testimony and consequently that the best way to characterize and explain forensic evidence may vary across forensic disciplines.

People with easier to pronounce names promote truthiness of claims.

When people make judgments about the truth of a claim, related but nonprobative information rapidly leads them to believe the claim–an effect called “truthiness” [1]. Would the pronounceability of others’ names also influence the truthiness of claims attributed to them? We replicated previous work by asking subjects to evaluate people’s names on a positive dimension, and extended that work by asking subjects to rate those names on negative dimensions. Then we addressed a novel theoretical issue by asking subjects to read that same list of names, and judge the truth of claims attributed to them. Across all experiments, easily pronounced names trumped difficult names. Moreover, the effect of pronounceability produced truthiness for claims attributed to those names. Our findings are a new instantiation of truthiness, and extend research on the truth effect as well as persuasion by showing that subjective, tangential properties such as ease of processing can matter when people evaluate information attributed to a source.

Make It Short and Easy: Username Complexity Determines Trustworthiness Above and Beyond Objective Reputation

Can the mere name of a seller determine his trustworthiness in the eye of the consumer? In 10 studies (total N = 608) we explored username complexity and trustworthiness of eBay seller profiles. Name complexity was manipulated through variations in username pronounceability and length. These dimensions had strong, independent effects on trustworthiness, with sellers with easy-to-pronounce or short usernames being rated as more trustworthy than sellers with difficult-to-pronounce or long usernames, respectively. Both effects were repeatedly found even when objective information about seller reputation was available. We hypothesized the effect of name complexity on trustworthiness to be based on the experience of high vs. low processing fluency, with little awareness of the underlying process. Supporting this, participants could not correct for the impact of username complexity when explicitly asked to do so. Three alternative explanations based on attributions of the variations in name complexity to seller origin (ingroup vs. outgroup), username generation method (seller personal choice vs. computer algorithm) and age of the eBay profiles (10 years vs. 1 year) were tested and ruled out. Finally, we show that manipulating the ease of reading product descriptions instead of the sellers’ names also impacts the trust ascribed to the sellers.

Nonprobative photos rapidly lead people to believe claims about their own (and other people’s) pasts

Photos lead people to believe that both true and false events have happened to them, even when those photos provide no evidence that the events occurred. Research has shown that these nonprobative photos increase false beliefs when combined with misleading suggestions and repeated exposure to the photo or target event. We propose that photos exert similar effects without those factors, and test that proposition in five experiments. In Experiment 1, people saw the names of several animals and pretended to give food to or take food from each. Then people saw the animal names again, half with a photo of the animal and half alone, and decided whether they had an experience with each. The photos led people to believe they had experiences with the animals. Moreover, Experiments 2–5 provided evidence that photos exerted these effects by making it easier to bring related thoughts and images to mind—a feeling that people mistook as evidence of genuine experience. In each experiment, photos led people to believe positive claims about the past (but not negative claims), consistent with evidence that feelings of ease selectively increase positive judgments. Experiment 4 also showed that photos (like other manipulations of ease) bias people’s judgments broadly, producing false beliefs about other people’s pasts. Finally, in Experiment 5, photos exerted more powerful effects when they depicted unfamiliar animals, and thus could most help bring information to mind. These findings suggest that nonprobative photos can distort the past without other factors that encourage false beliefs, and that they operate by helping related thoughts and images come to mind.

Evidence that photos promote rosiness for claims about the future

When people rapidly judge the truth of claims about the present or the past, a related but nonprobative photo can produce “truthiness,” an increase in the perceived truth of those claims (Newman, Garry, Bernstein, Kantner, & Lindsay, 2012). What we do not know is the extent to which nonprobative photos cause truthiness for the future. We addressed this issue in four experiments. In each experiment, people judged the truth of claims that the price of certain commodities (such as manganese) would increase (or decrease). Half of the time, subjects saw a photo of the commodity paired with the claim. Experiments 1A and 1B produced a “rosiness” bias: Photos led people to believe positive claims about the future but had very little effect on people’s belief in negative claims. In Experiment 2, rosiness occurred for both close and distant future claims. In Experiments 3A and 3B, we tested whether rosiness was tied to the perceived positivity of a claim. Finally, in Experiments 4A and 4B, we tested the rosiness hypothesis and found that rosiness was unique to claims about the future: When people made the same judgments about the past, photos produced the usual truthiness pattern for both positive and negative claims. Considered all together, our data fit with the idea that photos may operate as hypothesis-confirming evidence for people’s tendency to anticipate rosy future outcomes.

Good Sound, Good Research: How Audio Quality Influences Perceptions of the Research and Researcher:

Increasingly, scientific communications are recorded and made available online. While researchers carefully draft the words they use, the quality of the recording is at the mercy of technical staff. Does it make a difference? We presented identical conference talks (Experiment 1) and radio interviews from NPR’s Science Friday (Experiment 2) in high or low audio quality and asked people to evaluate the researcher and the research they presented. Despite identical content, people evaluated the research and researcher less favorably when the audio quality was low, suggesting that audio quality can influence impressions of science.

The Characteristics of Directive Future Experiences and Directive Memories.

People can mentally travel to the future to “prelive” events they might experience. This ability to mentally prelive future events is closely related to the ability to mentally relive past events. People report traveling back in time to relive experiences that happened in their past in order to direct their behavior in the present, so people may imagine future experiences for similar reasons. If people use imagined future experiences to direct their behavior, how do the characteristics of these directive future experiences compare with those of directive memories? To address that question, we asked subjects to describe either an imagined future event or a remembered event that had helped them when they thought of it. We then asked each subject to rate phenomenological and memorial characteristics of his or her event, including how vivid and emotionally evocative it was, how often he or she rehearsed it, and its emotional valence. We also classified each event according to its relationship with the cultural life script (CLS). Across two experiments, we found that directive future experiences were more evocative, more frequently rehearsed, more positive, and more often drawn from the CLS than directive memories. These results suggest that, although imagined future experiences may, like memories of past experiences, serve a directive function, the characteristics of these two classes of experience are distinct. We also found that many directive memories were negative, suggesting a special role for these memories in guiding behavior. The consequences of mental time travel on behavior warrant further study.

Photos That Increase Feelings of Learning Promote Positive Evaluations.

Research shows that when semantic context makes it feel easier for people to bring related thoughts and images to mind, people can misinterpret that feeling of ease as evidence that information is positive. But research also shows that semantic context does more than help people bring known concepts to mind—it also teaches people new concepts. In five experiments, we show that when photos increase these feelings of learning, they also increase positive evaluations. People saw fictitious wine names and evaluated claims about each. Within subjects, wine names appeared with (or without) photos depicting the noun in the names. We found that photos promoted positive evaluations, did so most when they were most likely to help people learn new words, and even led people to think the wines tasted better. Together, these findings fit with the idea that semantic context promotes positive evaluations in part by teaching people new concepts.