The Five Senses and Beyond: The Encyclopedia of Perception - Jennifer L. Hellier 2017


Desensitization can have different meanings in medicine and science. For instance, desensitization is a process to reduce or alleviate a person’s or animal’s adverse reaction to a stimulus. In rare cases, certain stimuli may actually cause a phobia in a person, such as seeing spiders (arachnophobia). Desensitization techniques can be used to reduce a person’s phobia. In neuroscience, desensitization generally refers to receptor desensitization, where the receptor cannot be activated or opened for a specific length of time even if the neurotransmitter is present. Finally, in the field of psychology desensitization is defined as the diminished emotional responsiveness to a negative or aversive stimulus after repeated exposure. When an action tendency associated with an emotion proves irrelevant or unnecessary, an emotional response is repeatedly evoked. Developed by psychologist Mary Cover Jones (1897—1987), desensitization is a process primarily used to assist individuals to unlearn phobias and anxieties. In 1958, Joseph Wolpe (1915—1997) developed a method of a hierarchical list of anxiety-evoking stimuli in order of intensity. This allowed individuals to undergo adaption. While medication is available for individuals, evidence supports desensitization with high rates of cure, especially in those who suffer from depression or schizophrenia.

Steps to Desensitization

First, the hierarchical list developed by Wolpe ranks an ordered series of steps from the least to the most disturbing fears or phobias. This is constructed between a client and therapist. The client is taught techniques in order to produce deep relaxation. While it is impossible to feel both anxiety and relaxation at the same time, it is important to ease the client into deep relaxation. This helps inhibit any feelings of anxiety. A guided reduction in fear, anxiety, or aversion, known as systematic desensitization, can be achieved by gradually approaching a feared stimulus as well as maintaining relaxation. When individuals are directly exposed to the stimuli and situations they fear, desensitization works best as anxiety-evoking stimuli are paired with inhibitory responses. This can be carried out with in vivo desensitization (performing in real-life situations) or as vicarious desensitization (acting out steps of the hierarchy so clients can observe modules of the feared behavior). The patient and therapist will slowly move up the hierarchy until the last item on the list is performed without any fear or anxiety.

Effects on Animals

Animals can be desensitized to their fears as well as humans can. A race horse, for example, who is afraid of the starting gate can be desensitized to fearful elements. These fearful elements may include but are not limited to the creak of the gate, the starting bell, and the enclosed space. Horses can be desensitized to these one at a time, in small doses.

Effects on Violence

One topic debated in science is whether violence is caused by the exposure to violence in the media including television, video games, and movies. Desensitization can also refer to the potential for reduced responsiveness to this actual violence. It has been suggested that violence may prime thoughts of hostility with the possibility of affecting the way humans perceive others and interpret their actions. Aversive responses including but not limited to increased heart rate, fear, discomfort, perspiration, and disgust have been associated with the initial exposure to violence in the media. Prolonged and repeated exposure to violence may reduce or habituate the initial psychological impact until violent images do not elicit these negative responses. Over time, an observer could become desensitized to media violence, both emotionally and cognitively. An experiment was completed with participants who played violent video games. This showed that gaming participants had lower heart rates and electrical skin response readings. This was interpreted as the individuals displaying a physiological desensitization to violence. However, these findings have not been replicated, and it has been questioned whether becoming desensitized to media violence specifically transfers to becoming desensitized to real-life violence.

Renee Johnson

See also: Carotid Body; Excitation; Free Nerve Endings; Perception

Further Reading

Engelhardt, Christopher R., Bruce D. Bartholow, Geoffrey T. Kerr, & Brad J. Bushman. (2011). This is your brain on violent video games: Neural desensitization to violence predicts increased aggression following violent video game exposure. Journal of Experimental Social Psychology, 47(5), 1033—1036.

Krahe, Barbara, Ingrid Moller, L. Rowell Huesmann, Lucyna Kirwil, Juliane Felber, & Anja Berger. (2011). Desensitization to media violence: Links with habitual media violence exposure, aggressive cognitions, and aggressive behavior. Journal of Personality and Social Psychology, 100(4), 630—646.

Mrug, Sylvie, Anjana Madan, & Michael Windle. (2016). Emotional desensitization to violence contributes to adolescents’ violent behavior. Journal of Abnormal Child Psychology, 44(1), 75—86.