Taste aversion was discussed briefly in one of the book chapters, and was very interesting to learn about. To start, taste aversion is an association people make between the taste of a specific food and an illness, believing that the food caused the illness, even in cases where that is not true. Taste aversion plays a huge role in helping keep us alive, and not only affects humans but animals as well. Many studies have been done since the 1940s on conditioned taste aversion, which is a form of classical conditioning in which a food item has been paired with an unpleasant thing (like an illness), which then becomes a conditioned aversive stimulus. A large majority of the experiments done with animals in labs have focused on rats and looked to find a way to control their population. One of the scientists studying taste aversion, John Garcia found many new discoveries relating to this topic that went against what the scientific community thought they knew about taste aversion at that time.
One such find was that taste aversions can be formed over long delays in time. It was found that evolution played a role in this aspect of taste aversion, specifically in allowing people the ability to associate a taste with the effects of illness after a single exposure in order to avoid eating that specific food again. The ability to relate food you eat and any delayed illness effects also helped increase the chance of human survival. These findings by Garcia also led to many other similar discoveries in other areas of psychology, specifically in how/when people and animals learn things.
Conditioned taste aversion has also been used when working with cancer patients undergoing chemotherapy. Patients have a tendency to develop taste aversions to food during the time they get treatment, so in one study children undergoing chemotherapy were given a novel food. It was found that the novel foods had a higher chance of being associated with any illness from their treatment then non-novel foods. So, it was demonstrated that if a patient consumed a novel food item before undergoing treatment as opposed to a non-novel food item, they were more likely to associate any side affects with the novel food, and their normal diets were not affected as much. To conclude, taste aversion is a very interesting adaption to learn about, and there are endless ways it can be applied to different fields of study to improve the lives of people.
Reference: DAVIDSON, T. L., & RILEY, A. L. (2017, February 6). Taste, Sickness, and Learning. American Scientist. https://www.americanscientist.org/article/taste-sickness-and-learning