How Science Is Harnessing Disgust to Revolutionize Medicine, Food, and Sustainability
Explore the ScienceWe've all experienced it—that visceral, automatic reaction to something foul, repulsive, or just plain icky. The curled upper lip, the wrinkled nose, the overwhelming urge to turn away. This is the "yuk factor" in action, an emotion so primitive and powerful that it can shape our decisions, beliefs, and behaviors in ways we scarcely recognize.
Disgust influences moral judgments and decision-making processes beyond our conscious awareness.
This primal emotion triggers distinct physiological changes that prepare the body to reject potential contaminants.
While universal, disgust responses vary significantly across cultures and personal experiences.
Disgust is universally experienced by humans across cultures, typically accompanied by a distinctive facial expression featuring a puckered lip and wrinkled nose. This isn't accidental—evolutionary psychologists believe this response developed as a protective mechanism against illness and death.
"Before we had developed any theory of disease, disgust prevented us from contagion."
As humans became a more social species, disgust's role expanded. Other humans represent potential disease carriers, prompting us to develop aversions to those who violate social hygiene conventions or who we perceive—rightly or wrongly—as carriers of sickness.
The idea that disgust plays a deeper role in everyday behavior emerged relatively recently. Psychologist Jonathan Haidt at the University of Virginia published a landmark paper proposing that instinctive gut feelings, rather than logical reasoning, primarily govern our judgements of right and wrong 1 .
Subsequent research has demonstrated that disgust operates largely outside our conscious awareness, influencing us in subtle but powerful ways.
This connection between physical and moral disgust reveals the emotion's far-reaching influence on human social behavior, affecting everything from personal relationships to political preferences.
In a clever experiment designed to investigate disgust's influence on social attitudes, David Pizarro and Yoel Inbar of Tilburg University used a rather unconventional research tool: fart spray.
The psychologists spent weeks tracking down the perfect aroma—one that smelled authentically of real flatulence but wasn't overpowering 1 .
The researchers primed a room with the faint but unmistakable scent of their carefully selected fart spray, then invited participants in to complete a questionnaire. The survey asked them to rate their feelings of warmth toward various social groups, including the elderly, immigrants, and homosexual men.
The results were striking: while the whiff didn't influence feelings toward many social groups, one effect stood out starkly. Participants in the smelly room, on average, felt significantly less warmth toward homosexual men compared to those in the non-smelly room 1 .
This finding aligns with previous studies showing that a stronger susceptibility to disgust is linked with disapproval of gay people. The experiment demonstrated that inducing disgust through a foul odor could temporarily increase prejudice against a socially stigmatized group.
| Domain | Effect of Disgust | Example |
|---|---|---|
| Moral Judgments | Increases severity of condemnation | People in disgusting environments judge shoplifting more harshly |
| Social Attitudes | Increases prejudice against stigmatized groups | Fart spray reduced warmth toward homosexual men |
| Political Preferences | Boosts conservative leanings | Disgust cues make people temporarily more conservative |
| Consumer Behavior | Lowers valuation of objects | People sell property for less when disgusted |
| Judicial Decisions | Harsher penalties for crimes | Disgusting crimes receive more severe punishments |
Perhaps nowhere is the challenge of overcoming disgust more pressing than in medicine, particularly in the emerging field of fecal microbiota transplantation (FMT).
The treatment involves transferring stool from a healthy donor to a sick recipient to restore their gut microbiota—the community of microorganisms that plays a crucial role in human health 7 8 .
FMT has shown remarkable effectiveness against Clostridium difficile, a potentially life-threatening bacterial infection that causes horrific diarrhea and is resistant to many antibiotics. Clinical trials have demonstrated that fecal transplants are approximately 94% effective against C. difficile infections 2 .
Researchers are developing innovative solutions to bypass disgust, such as creating bacterial spore pills instead of using actual feces 2 .
Human waste represents not just a medical resource but also a potential sustainable input for agriculture—if we can overcome our revulsion.
Approximately 70% of sewage sludge in the UK is disposed of on farmland, a practice allowed under EU legislation and common in several European countries 4 . This approach offers economic benefits, with alternative disposal methods costing 30-50% more 4 .
| Benefit Type | Specific Advantages | Research Findings |
|---|---|---|
| Agricultural | Maintains crop yields | OMF formulations produce comparable yields to conventional fertilizers |
| Environmental | Reduces waste disposal | Alternative disposal methods cost 30-50% more |
| Soil Health | Increases organic matter | Addition of biosolids increases microbial biomass |
| Climate | Lower GHG emissions | Composting approach has 1/4 to 1/27 net GHG emissions of alternatives |
| Resource Recovery | Addresses phosphate shortages | Recovers valuable nutrients from waste streams |
The "yuk factor" presents perhaps its most challenging barrier in the realm of food, where cultural traditions and personal preferences collide with sustainability imperatives.
Approximately two billion people worldwide regularly eat insects, but Western consumers have been far more reluctant to embrace this protein source .
Research from De Montfort University in the UK found that consuming insect-based foods is generally "unappealing" to British consumers. Only 13% of people surveyed were willing to consume insects regularly, with disgust cited as the primary barrier 9 .
This resistance persists despite insects' impressive nutritional profile. They are rich in protein, fats, vitamins, minerals, and fiber, with certain species offering good sources of zinc, calcium, and iron 9 .
| Nutrient Type | Insect Examples | Comparison to Traditional Foods |
|---|---|---|
| Antioxidants | Grasshoppers, silkworms, crickets | 5x higher than fresh orange juice |
| Protein | Cricket flour | 70% protein by weight |
| Minerals | Various insects | Good sources of zinc, calcium, iron |
| Vitamins | Mealworms | Generally higher vitamin content than beef |
| Fats | African caterpillars | Rich in polyunsaturated fatty acids |
Studying disgust presents unique methodological challenges, as researchers must ethically induce and measure this powerful emotion. The following table highlights key approaches and materials used in disgust research.
| Research Tool | Function | Example Use |
|---|---|---|
| Odor Induction | Priming disgust response | Fart spray experiments on social attitudes |
| Visual Stimuli | Eliciting disgust through images | Pathogen pictures to trigger disease vigilance |
| Film Clips | Inducing sustained disgust | Trainspotting toilet scene for disposal effect |
| Implicit Association Tests | Measuring unconscious disgust | Assessing meat disgust without self-report biases |
| Physiological Measures | Tracking biological responses | Heart rate, skin conductance during disgust induction |
| Self-Report Scales | Capturing conscious experiences | Disgust sensitivity questionnaires |
In some cases, rather than overcoming disgust, researchers and advocates are finding ways to harness this powerful emotion for beneficial purposes.
One University of Exeter study found that a significant percentage of meat eaters have a disgust response to meat, suggesting the "yuk factor" could be leveraged to help people reduce their meat consumption 6 .
Beyond harnessing disgust directly, education and reframing offer powerful approaches to overcoming inappropriate disgust responses.
In the case of using human waste in agriculture, clearly communicating the safety protocols and scientific evidence can help address public concerns 4 .
Similarly, with insect consumption, emphasizing familiar reference points can help bridge the disgust gap.
Perhaps the most effective strategy for overcoming disgust is product transformation—processing materials until they no longer trigger disgust responses.
Disgust, once dubbed "the forgotten emotion of psychiatry," has revealed itself as a powerful force shaping human behavior in ways both subtle and profound. From moral judgments to medical innovations, political preferences to dietary choices, this primitive emotion influences nearly every aspect of our lives, often without our conscious awareness.
"I think it's very possible to override disgust. That's my hope, in fact. Even though we might have very strong disgust reactions, we should be tasked with coming up with reasons independent of this reflexive gut reaction."
As research continues, scientists are developing increasingly sophisticated approaches to either harness or circumvent disgust for beneficial purposes. Graph neural networks now show promise in predicting odor properties of molecules, potentially helping develop less-disgusting alternatives for medical treatments 5 .
The challenge of overcoming the "yuk factor" represents more than just a scientific curiosity—it offers a path to more sustainable medical practices, environmentally friendly food systems, and perhaps even a more rational society. By understanding this powerful emotion, we can harness its protective power while preventing it from dictating choices that demand reasoned consideration.