Taste aversion is a strong dislike for a certain food or flavor. A taste aversion or a conditioned taste aversion develops when an animal or a human associates a certain food with symptoms of sickness (vomiting and nausea) that were caused by toxic, poisonous, or spoiled food. Taste aversions can be so strong that it only takes one episode of associating a food with sickness for the taste aversion to develop.
Taste aversions are common in persons receiving chemotherapy, which can be dangerous as each time the patient eats a new food, he or she develops a new taste aversion. This is because the medicine caused the nausea or vomiting, but the patient associated the sickness with ingesting the food. Eventually, chemotherapy patients do not want to eat, which can slow down their recovery as well as be dangerous to their overall health.
Taste Aversion Experiments
American psychologist John Garcia (1917—2012) was most noted for his conditioned taste aversion experiments performed in the 1950s. Garcia was observing a rat’s behavior following a session of radiation. He found that the rat would develop a taste aversion to the food it ate just prior to the radiation treatment. At the time, scientists believed that taste aversions would develop after a single trial with a long delay between the ingestion of the food and the sickness. Thus, to better understand the occurrence of taste aversion, Garcia gave three groups of rats sweetened water and then followed it with Group 1 receiving no radiation, Group 2 receiving mild radiation, and Group 3 receiving strong radiation. He then measured the amount of sweetened water they would drink after the radiation or no radiation session. The rats with both mild and strong radiation drank significantly less sweetened water compared to nonirradiated rats. This finding showed that a long delay was not required to develop a taste aversion and that an event causing nausea could produce the association with the food. Thus, the study of conditioned taste aversion began.
Behavior and Physiology
Survival of a species is a paramount trait that is innate in all animals. Behavioral scientists and psychologists posit that taste aversions are a type of survival mechanism or an adaptive trait that teaches the animal to avoid toxic or poisonous foods, such as poisonous plants (e.g., oleander, foxglove, and rhubarb leaves) and berries (e.g., nightshade, holly, and pokeweed berries). By causing the animal to vomit or be nauseated, the animal will stop eating the plant or berry before it causes severe harm or death. This strong association of a food with sickness will protect the animal so that it will avoid other similar plants or berries and ultimately avoid future toxicities or poisonings.
The development of a taste aversion, however, can be unintentional. Specifically, a taste aversion can occur because of other events or other substances and not because of the food itself. Consider the following example of an event causing the taste aversion. A person at an amusement park eats a hot dog. Right after he eats, the person rides a fast spinning ride like the Tea Cups at Disneyland, which makes him vomit. The spinning ride actually caused the nausea or sickness, but the person associates the hot dog as the cause of the vomiting. For an example of another substance causing a taste aversion, consider a young child with a very loose tooth eating corn on the cob. The child bites into the corn, which results in the tooth falling out and the gum bleeding. The mixture of blood with the corn can cause a sickening taste or feeling. Thus, the child will develop a taste aversion to the corn, when it was the blood that caused the nausea. Both of these types of instant taste aversion can last for years and may never become extinct.
Disease and Treatments
Patients with cancers often receive chemotherapy and/or radiation to treat their disease. As shown by Garcia, this can lead to taste aversions. It is important to note that a person does not need cognitive awareness for a taste aversion to develop. This means that the person does not have to recognize the connection of the cause and the effect or the food and the sickness. Chemotherapy patients are hungry and hope to enjoy their food, but the drugs make them sick and cause their body to reject the food. Thus, research has focused on developing strong antiemetic (antinausea and antivomiting) drugs to counteract and prevent the development of taste aversions for cancer patients as well as for motion sickness.
Jennifer L. Hellier
See also: Dizziness; Emesis; Hypergeusia; Hypogeusia; Nausea; Taste System
Bernstein, Ilene L. (1999). Taste aversion learning: A contemporary perspective. Nutrition, 15(3), 229—234.
Carelli, Regina M., & Elizabeth A. West. (2014). When a good taste turns bad: Neural mechanisms underlying the emergence of negative affect and associated natural reward devaluation by cocaine. Neuropharmacology, 76(B), 360—369.
Garcia, J., D. J. Kimeldorf, & R. A. Koelling. (1955). Conditioned aversion to saccharin resulting from exposure to gamma radiation. Science, 122(3160), 157—158.