The stereotype is common in film and television, but it has its basis in real life: men tend to have less scruples in certain situations than women, who They tend to feel more disgust in general.
But it turns out there is science beyond the stereotype: in several primate species, including humans, researchers have found that adult females are more sensitive as disgusting as the males, pick up the magazine National Geographic.
For example, female gray mouse lemurs and Japanese macaques are more likely than males to reject contaminated food, while female western lowland gorillas and olive baboons They tend to avoid other animals with skin infections.
The reason for such meticulousness? According to scientists, it can reduce the incidence of diseases in females, from parasitic infections to sexually transmitted diseases.
Cecile Sarabiana cognitive ecologist at the Institute for Advanced Studies in Toulouse, France, goes a step further: She suggests that the cumulative effects of female disgust (being more selective about what to eat and minimizing exposure to infections) may be one reason why Female primates live longer than males.
As a graduate student at Kyoto University In the 2010s, Sarabian observed Japanese macaques as they foraged on Kojima Island.
He soon realized that males and females prepared their meals very differently: for example, a female macaque usually cleans the acorns which he collects from the leaf litter before putting them in his mouth.
On the other hand, there seems to be “fewer precautions, even less research among males”who are more likely to devour food without even looking at it, he says.
Sarabian later discovered that Kojima’s females were not only finicky, but had less likely to be infected with soil-transmitted helminthsan intestinal parasite that is transmitted through feces, which males. Scientists know little about how these widespread infections affect the health of macaques, but there is evidence that females treated for the disease have greater body weight and reproductive success, Sarabian says.
In subsequent years, more examples have emerged. Female olive baboons in Tanzania they refuse to mate with males infected with treponemathe contagious bacteria that causes syphilis in humans and creates “very unpleasant and disgusting” lesions around the baboon’s butt, he says.
Female western lowland gorillas in the Republic of the Congo take more drastic measures. When a male develops pale spots on his face, another sign of treponema infection, some females leave the herd in search of a healthier population.
In addition to observing wild behavior, researchers also conduct field experiments using a ‘universal disgust inducer’ (usually poop) to observe the limits of disgust. After all, avoiding the risk of infection has its costs: grimacing due to contamination can mean you skip a meal.
In one experiment, Sarabian offered different foods placed on piles of excrement to Kojima macaques. While a grain of wheat placed on excrement seemed appetizing to about one in three macaques, in 100% of the trials, including females, ate half a peanut (which has 16 times more calories). “In that case, no one can avoid it. It is too high a value,” says Sarabian.
Studying disgust in humans requires a little more subtlety: offering food with excrement to people is frowned upon.and, even in an experimental context.
Instead, researchers show volunteers pictures of potentially unpleasant scenes or ask them to imagine scenarios, “like stepping in feces with bare feet, or finding a worm in your food, or eating raw chicken, or see a rat in the kitchen”and rate their disgust on a numerical scale, explains Tara Cepon Robins, a biological anthropologist at the University of Colorado, Colorado Springs.
At least in Western societies, women do better than men on these measures of disgust. Robins and her team found that among the Shuar, an indigenous group in Ecuador, those who rated Robins’ descriptions of scenes as less disgusting had more likely to be infected with bacteria and viruses.
The study of 75 people found no differences between the sexes, but Robins suspects that is due to the wide age range among the participants. A generational change that has led many Shuar to adopt a more modern lifestyle (such as changing dirt floors to cement and improving sanitary conditions for cooking and drinking water) has also made them more aware of pathogens.
“The more you can control your environment, basically, the more disgusted you are,” Robins says. In general, the disgust response appears to act as an advanced defense of the primate immune system. “That’s what disgust is all about: we are programmed to feel disgust for things that have hurt people in the past,” Robins explains.
The caution of females against possible sources of infection “would make sense from an evolutionary perspective”says Sarabian, since “we, the females, are the ones who give birth and take care of the young.”
Not just childbirth and parenting They do not increase the probability of infection for mothers, but the risks are greater, since females can transmit diseases to their offspring.
Some researchers maintain that disgust is accentuated when we are more vulnerable to infections, e.g. early in pregnancywhen the immune system is suppressed to avoid ‘friendly fire’ on the developing embryo.
A recent study that examined disgust sensitivity during the first trimester of a woman’s pregnancy found that the more disgusted mothers-to-be were by things like soured milk and cockroaches, less evidence of immune response researchers found circulating in their blood.
No matter how much we intellectualize unpleasant phenomena, we cannot escape them: after more than a decade of exposure to poop, bodily fluids, and other disgusting stimuli, Sarabian says she is more horrified than ever.
“I am now much more aware of the things that can put me at risk in my environment,” he says. “Disgust is not an emotion that you can easily get rid of.“he concludes.