A new study sheds light on the deep-seated human preference for all things “natural.” Published in Social Psychological and Personality Science, the research shows that this bias extends beyond words, influencing actual decisions—even when those decisions involve potential risks, like taking a drug or eating food that might cause discomfort.
The researchers behind the new study were intrigued by the well-documented naturalness bias—the widespread preference for items described as natural over synthetic. Prior studies have shown that this bias extends across various domains, from food and medicine to personal care products. However, much of the existing research relied on self-reported preferences in hypothetical scenarios, leaving a gap in understanding how the bias influences actual behavior.
“Most of us love nature. Waterfalls, mountains, forest trails, parks, and other green spaces provide endless enjoyment. Yet, can the love of nature and naturalness in general bias our beliefs in some situations?” said study author Brian Meier, a professor of psychology at Gettysburg College.
“My colleagues and I have been interested for some time in how terms related to ‘nature,’ ‘natural,’ or ‘naturalness’ might bias our perceptions of a host of items. In the present case, we focused on medicines. We have several papers showing that labeling a drug as ‘natural’ versus ‘synthetic’ affects attitudes, safety ratings, and choices in self-reports. Simply put, on average, people think natural drugs are better, safer, and a good choice compared to drugs described as synthetic or human-made.”
“Yet, much of this prior work has been carried out using hypothetical scenarios or situations where people tell researchers what they think they would feel or do,” Meier explained. “Therefore, it is unclear if people would actually use natural versus synthetic items when we measure their observable behavior.”
The researchers conducted four experiments, each designed to test participants’ choices and behaviors in different contexts.
The first experiment focused on a scenario involving a “performance-enhancing” drink. The participants, 174 college students, were informed that the study aimed to evaluate the effectiveness of a drink described as either natural or synthetic in improving strength. Participants completed an initial self-control task, where they measured their grip strength by holding a dynamometer at a set pressure. They were then offered the opportunity to try one of the drinks, described as natural or synthetic, before repeating the task.
In reality, both drinks were simply water, but the participants believed they were consuming a functional performance enhancer. The researchers recorded their choices and whether they followed through with drinking it. Remarkably, 84% of the participants opted for the drink labeled as natural, demonstrating a strong preference for naturalness even in this relatively low-risk scenario.
The second experiment introduced a more consequential context by simulating a medical procedure. Fifty-two students were told they could volunteer to test a blood-coagulating drug delivered via a finger prick. The drug was described as either natural or synthetic, but the finger stick itself was a sham; no actual lancet was used, and no drug was administered. To enhance the realism, the procedure was staged with typical medical equipment, such as gloves and alcohol wipes, and carried out by a research assistant wearing a lab coat.
Despite the potential discomfort or risk implied by the procedure, 73% of the participants who agreed to participate chose the natural version of the drug. This result indicated that even when a decision involved physical consequences, the naturalness bias remained a significant factor in participants’ choices.
The third experiment examined how the naturalness bias played out in the context of food, specifically chocolate consumption. Ninety-eight students were offered the chance to taste chocolate that was described as being made with either natural or synthetic cocoa. Participants were told that the cocoa might cause stomach discomfort, adding a layer of potential risk to their decision. After selecting and eating the chocolate, they rated its taste and any discomfort they experienced. Meier and his colleagues found that 84% of the participants who volunteered chose the natural cocoa chocolate.
The fourth and final experiment moved outside the laboratory and into a public setting. It included 200 participants, making it the most diverse of the studies. The researchers approached passersby on and around a university campus and asked them to evaluate and choose between stickers described as being made with either natural or synthetic ink. After rating the stickers for appeal and quality, participants were allowed to keep one as a token of appreciation.
Here, 66% of the participants chose a sticker labeled as natural. Although the stakes in this scenario were low, the preference for natural options was still evident. The participants’ ratings of the stickers also revealed that they perceived the natural ones to be of higher quality and more appealing.
“Most of the participants who completed the studies were biased by the term ‘natural’ in their behavior,” Meier told PsyPost. “That is, around 75-80% of participants in these studies chose a natural versus synthetic item and actually followed through with the behavior in question (e.g., chocolate consumption or drug ‘injection’). These results suggest to us that this naturalness bias can influence behavior that some people might consider risky.”
The researchers propose several future directions for this line of inquiry, including identifying individuals most and least susceptible to the bias, exploring ways to mitigate its influence, and examining how the bias impacts consequential medical behaviors, such as vaccine uptake.
The study, “Perceived Naturalness Biases Objective Behavior in Both Trivial and Meaningful Contexts,” was authored by Brian P. Meier, Eric E. Noreen, Li-Jun Ji, Michael B. Fellman, and Courtney M. Lappas.