Taste Aversion Learning

Taste aversion learning, or conditioned taste aversion, refers to a distaste or repugnance for a particular type of food due to a previous incident or stimulus with unfavorable consequences. Taste aversion learning, which tends to fall in the realm of psychology, can be attributed to certain molecular signaling and physiological pathways. The concept of taste aversion is based on a cause-and-effect relationship; a specific food can trigger memories of illness. In the case of obesity, taste aversion learning is a potentially useful tool for weight control and healthy eating choices.

Taste aversion learning is a type of associative learning known as classical conditioning. Classical conditioning requires the presence of an unconditioned stimulus that automatically evokes an unconditioned response. The point of classical conditioning is to manipulate the relationship of the unconditioned response and stimulus and promote the onset of a certain conditioned response. In behavioral therapy the conditioned response will be more beneficial to the subject, in whatever area the therapy is seeking to address, and repetition will eventually lead to the removal of the more detrimental unconditioned response from the subject's lifestyle.

Aversion therapy is a type of psychological therapy. The treatment occurs when a patient is exposed to a stimulus that is immediately followed by some kind of discomfort. The objective of aversion therapy is to condition the patient to associate the stimulus with something unpleasant that leads the patient to cease the targeted behavior. An aversive stimulus is an unconditioned stimulus, and this stimulus produces an unconditioned response. With aversion therapy, the patient should learn to experience a new, conditioned response with each stimulus, and successful treatment will cause the compulsion to succumb to the former, unconditioned response to subside and eventually disappear. Aversion therapy has been used in the treatment of substance abuse, but the application of its principles to combat overeating and poor eating choices needs to be further explored.

Taste aversion learning occurs when one learns to associate the taste of one food with unpleasant symptoms such as nausea or vomiting. Taste aversion is a trait that can be adapted and is actually a survival mechanism that ensures that one stays away from potentially harmful foods or beverages that are poisonous or spoiled. The association that develops between ingestion of the harmful substance and knowledge of the symptoms that occur after its ingestion ensures the prevention of future consumption.

Taste aversion learning can also occur when an association is taught that links the ingestion of a specific food with a forced task. Animal studies have compared the strengths of conditioned taste aversion with forced activities such as running and swimming [Page 736]for varying lengths of time. Injections with substances such as lithium chloride have also exhibited strong taste aversion learning.

Certain molecular events allow for the acquisition of taste aversion, and many of these processes are due to an association with fos-like immunoreactivity and taste novelty. Hormonal relationships have also been considered. Some studies have targeted leptin as an influence in the development of taste aversion learning. While results for leptin studies have suggested that it is not related to the attainment of taste aversions, the nonspecific melanocortin agonist MTII was found to produce conditioned taste aversions.

...