Does disgust predict people’s judgment of genetically modified food? It depends on what you mean by “disgust”.

By Corey Cusimano, Robert Leeman, and Edward Royzman

Are our social attitudes a product of our emotions and “gut-feelings”? A popular view among social psychologists holds that the answer is yes and that feelings of disgust in particular can lead to harsher social judgments, especially about behaviors that evoke so-called “purity” concerns, e.g., concerns about the right way to eat, dress, and have sex. Some have also suggested that feelings of disgust can explain why we condemn certain behaviors even when they do not seem objectively harmful or unjust. For example, many people seem to oppose genetically modified foods. Yet, evidence indicates that their benefits greatly outweigh their harms. Could people’s refusal to change their view be mainly a product of evidence-blind disgust? As we recently have argued, it all depends on what you mean by “disgust”.

A 2016 study found a modest but robust association between people’s sensitivity to “disgust” and their belief that genetically modified food (henceforth, GM-food) should be banned, no matter how great the benefits and minor the harms. But, in line with much of the previous research, this study assessed people’s sensitivity to being “disgusted” in a way that makes it impossible to determine whether the construct being assessed was truly sensitivity to disgust as scientists use the term. The scientific use denotes feelings of oral inhibition (wanting to throw up, gagging, loss of appetite) or gustatory discomfort. From Darwin on, disgust scholars viewed disgust as a category of food rejection, whose origin is the “mammalian bitter taste rejection system”, whose physiological correlate is nausea, and whose facial emblem is the “gape” (or the “sick face”). Crucially, the discriminant scientific use is about oral inhibition, not about general sensitivity to risk, norm violations, or being generically “upset”. Our key concern was that the authors of this study (along with previous studies on this topic!) did not assess the precise scientific construct, disgust-the-feeling, but engaged with its hazy folk counterpart—disgust-the-word.

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To sketch the problem broadly, we must look at how psychologists commonly measure trait disgust. The process is reasonable enough – researchers conjure up a list of prima facie valid “disgust-eliciting events” such as shaking hands with someone with sweaty palms or seeing a cockroach scurry across the floor – then ask the subject to indicate how “disgusting” they find each at that time. One problem is that “disgust-eliciting events” are so much more than that. A bleeding sore may stir up dread as well as nausea, an abandoned dog poop is likely to prompt your disapproval at an unseen dog-walker (as well make you gag at the poop), and a stranger with sweaty palms might creep you out in addition to making you lose your appetite. This raises the question: Given the polysemous nature of disgust-the-word (see this, thisthis, and this) and multi-factorial nature of “disgusting stimuli”, what if  people reporting that they are more or less “disgusted”are using the term as a stand-in for different aversions? And what if individual differences in disgust proper, when properly measured as oral inhibition and distinguished from other feelings and sensations, do not predict the social attitudes at all?

To measure people’s feelings more precisely, we used a re-constructed disgust scale, one with a menu of non-disgust options that the expansive, ambiguous “disgusting” might have conveyed. These included anger or social disapprobation, feeling itchy or uncomfortable in one’s skin, feeling frightened, and so on, all in addition to assessing disgust as a food rejection response. As much as possible, the response options were couched in concrete and unambiguous terms – e.g., “loss of appetite”,” gagging” in lieu of “bothered” or “disgusted”—to communicate a discreet and qualitatively unique experience in every case. To reduce spillover/demand characteristics, affective and social responses were measured multiple weeks apart. To see how our new and more elaborate measure compared to the old one, we measured disgust-the-word (“disgusting”) alongside (but weeks apart from) disgust-the-feeling (concrete symptoms of oral inhibition).

Our first result confirmed our long-standing worry—disgust-the-word was not a special proxy for disgust-the-feeling. In fact, “disgusting” was strongly correlated with every negative desire or sensation that we sampled. Furthermore, “disgusting” was no more strongly correlated with disgust-the-feeling than it was with other feelings that we measured: epidermal discomfort, desire to retaliate or criticize, wanting to run away, or feeling creeped out.

Was disgust-the-feeling uniquely predictive of people’s tendency to favor restrictions on GM-food (harms and benefits notwithstanding)? We did not find this to be the case. The correlation between oral inhibition and people’s attitudes to GM-food was essentially zero. On the other hand, disgust-the-word did rather well, serving as strong and significant a predictor of opposition to GM-food in our study as it did in the study that inspired us. A similar pattern held true when our measure of attitudes toward new tech was expanded to include stem cell research and nuclear energy.

Was there any affective reaction that uniquely predicted people’s opposition to GM-food?  Yes, there was. People’s sensitivity to feeling “creeped out” – a measure of their tendency to be unnerved by uncertain or ill-defined threats–predicted their attitudes to some degree. This dovetails nicely with a substantial body of work linking morality to threat sensitivity and harm (e.g., see this, this, and this as well as this, and this). Ultimately, it appears that our subjects’ opposition to GM-food was less about revulsion at what it is and more about the threats that it may pose.

So, does disgust underly our social opposition to issues like GM-food?  It all depends on what you mean by “disgust”.  If what one means is the feeling of being disgusted—the mammalian oral rejection response to “yucky things”—the answer appears to be a no. But if what one means is general dislike or concern with potential consequences, the answer appears to be a yes. It is up to each individual researcher to decide which meaning to pursue, then give it with precision to the subject.

 

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