The electrodes go on first. Eight of them, pressed into a snug cap over the scalp, plus a couple more clipped to the fingers to catch the heart’s faint electrical chatter. Then a researcher in a lab in central Portugal slides a small brown bar across the table and says, simply, that the volunteer is about to eat a protein bar. What the volunteer does not always know is that the bar is made from insects. And what nobody in the room knows yet is that the body is about to give a rather different answer than the mouth will.
That gap, between what people say about eating bugs and what their nervous systems do, is the thing Andreia Ferreira set out to measure. A PhD candidate at the University of Beira Interior, she and her colleagues wanted to get underneath the survey responses, where the polite no often lives.
The premise is hardly frivolous. With the global population heading past nine billion by mid-century and protein demand climbing with it, insects keep coming up as a low-footprint alternative to meat: less land, less water, fewer greenhouse gases, and a respectable load of iron, zinc and calcium per bite. The European Union recognized them as a novel food back in 2018, and you can now buy crickets, locusts and mealworms (frozen, dried, or milled into powder) across the bloc. The catch has always been the human one. Westerners, the research kept finding, are put off. Disgust, supposedly, does the blocking.
So the team built an experiment to watch the disgust happen. Or not.
What the Body Said
Thirty-eight adults, none of whom had ever knowingly eaten an insect, sat through a tasting wired up to an electroencephalography headset and an electrocardiogram. They each ate two bars, one insect-based and one ordinary cereal, both flavored with apple and cinnamon so the contest was reasonably fair. The kit recorded brain waves and heart rate before, during and after each mouthful. Some volunteers were told the truth about what they were chewing. Others were told the insect bar was just cereal, a small deception designed to separate the body’s reaction from the mind’s expectations.
The heart gave it away. Beats per minute climbed during the insect bar in a way they didn’t for the cereal, a signature the team reads as arousal, the body sitting up and paying attention. The brain agreed: more activity in the bands tied to attention and visual processing, the neural equivalent of leaning in for a closer look. Crucially, this happened even when people had no idea they were eating insects. The response, in other words, wasn’t a story the volunteers were telling themselves about bugs. It was something more immediate than that.
“The findings were very surprising,” Ferreira said. “This was really an unexpected result as literature said to us that consumers tend to reject these novel foods. The results show us the relevance of tasting experiments on promoting this new alternative.”
Then came the part that genuinely complicates the textbook. After tasting both bars, the volunteers were asked a blunt question: which did you prefer, the insect or the cereal? More of them chose the insect bar. In two of the four subgroups, roughly nine in ten picked it, including, awkwardly for tidy interpretation, several people who had been misled about which bar was which and still ended up praising the one made of bugs. The earlier work in this area, a 2017 study that watched people cook with mealworms, had logged anxiety and something close to an urge to flee. This time the urge to flee never showed up.
None of which means the disgust isn’t real. It is, and it arrives right on cue, in the second or two before the bar reaches the lips. The team’s argument is narrower and, perhaps, more useful: disgust may not be the thing that actually decides the matter.
Surprise, Not Squeamishness
Dig into the pre-tasting survey and a different culprit emerges. Awareness was strikingly thin. Fewer than half the participants knew insect foods were even for sale in Portugal, only 8 per cent had ever spotted them on a shelf, and a mere 3 per cent could name a species cleared for sale (the grasshopper, mostly). The emotion that came up first, ahead of fear and well ahead of disgust, was surprise. And surprise, the researchers point out, is not a verdict. It is a startle, a reaction to novelty rather than a judgment of worth. Disgust can sink a food for good; surprise just means you didn’t see it coming.
There are reasons to hold the conclusions loosely. The sample was small, drawn from one country, and the two bars (this is the honest snag) differed slightly in texture and sweetness, so some of the brain’s interest might be down to the snack rather than the insect. The hardware was the consumer-grade sort, twitchy about chewing and chatter, which is partly why seven volunteers’ recordings had to be binned. The authors are upfront about all of it.
Still, the practical thread is hard to ignore, and it points somewhere unfashionable: not at persuasion, but at exposure. If the barrier is unfamiliarity dressed up as revulsion, then arguing with people may matter less than simply handing them a sample. Free tastings, in-store trials, the bar tucked into a familiar shape and a familiar flavor, the things marketers reach for when a product is new rather than feared. Tellingly, fretting about the planet did not predict who would try insects; in this group, sustainability concern and future appetite barely tracked at all. The pitch, Ferreira suggests, has to do more than wave the word “new” around.
For now the finding sits as a small, sharp correction to a comfortable assumption, that we know our own minds about what we will and won’t put in our mouths. The volunteers in that Portuguese lab thought they knew. Their hearts, beating a little faster over a bar they’d been taught to refuse, had other ideas.
Source: https://doi.org/10.1037/npe0000215
Frequently Asked Questions
If insects are so disgusting to Western eaters, why did people prefer the bug bar?
Because the disgust may be shallower than it looks. In this study the body actually leaned in (faster heart rate, sharper attention) rather than recoiling, and the same response showed up even when people didn’t know they were eating insects. The researchers think what we call disgust is often just surprise at something unfamiliar, which fades fast once you’ve actually tasted the thing.
Is it true that worrying about the environment makes people more willing to eat insects?
Not according to this data, which is part of what makes it interesting. Concern for sustainability barely predicted who would consider eating insects in the future. Direct experience, a free sample, a familiar flavor, seemed to move people far more than any green argument did.
How can brain and heart readings reveal something a survey can’t?
Surveys capture what people are willing to say, which is often the polite, rehearsed answer. EEG and ECG instead pick up arousal and attention in real time, before the conscious mind edits the response. When the two disagree, as they did here, the physiological signal can expose a curiosity people don’t admit to even themselves.
Could simply handing out free samples really change how people eat?
That’s the practical takeaway the researchers lean toward. If the obstacle is unfamiliarity rather than genuine revulsion, then exposure, in-store tastings and insects folded into familiar snack formats, may do more than any persuasion campaign. It’s an early finding from a small study, but it points marketing in a notably different direction.
Should we trust a result based on just 38 people?
With caution, and the authors say as much. The sample was small, from a single country, and the two bars differed slightly in texture and sweetness, so some of the brain’s interest might reflect the snack rather than the insect. It’s best read as a sharp challenge to a comfortable assumption, not the last word on it.
