Ophidiophobia is a particular type of specific phobia, the abnormal fear of snakes. It is sometimes called by a more general term, herpetophobia, fear of reptiles. The word comes from the Greek words "ophis", snake, and "phobia" meaning fear. About a third of adult humans are ophidiophobic, making this the most common reported phobia. In The Handbook of the Emotions, psychologist Arne Öhman studied pairing an unconditioned stimulus with evolutionarily-relevant fear-responseneutral stimuli versus evolutionarily-irrelevant fear-response neutral stimuli on human subjects and found that ophidiophobia and arachnophobia required only one pairing to develop a conditioned response while mycophobia, anthophobia, and phobias of physical representations of polyhedra required multiple pairings and went extinct without continued conditioning while the conditioned ophidiophobia and arachnophobia were permanent. Psychologist Paul Ekman cites the following anecdote recounted by Charles Darwin in The Expression of the Emotions in Man and Animals in connection with Öhman's research: Similarly, psychologists Susan Mineka, Richard Keir, and Veda Price found that laboratory-raisedrhesus macaques did not display fear if required to reach across a toy snake to receive a treat unless the macaque was shown a video of another macaque withdrawing in fright from the toy, while being shown a similar video of another macaque displaying fear of a flower produced no similar response. Psychiatrists Isaac Marks and Randolph M. Nesse and evolutionary biologist George C. Williams have noted that people with systematically deficient responses to various adaptive phobias are more temperamentally careless and more likely to end up in potentially fatal accidents and have proposed that such deficient phobia should be classified as "hypophobia" due to its selfish genetic consequences. A 2001 study at the Karolinska Institute in Sweden suggested that mammals may have an innate negative reaction to snakes, which was vital for their survival as it allowed such threats to be identified immediately. A 2009 report of a 40-year research program demonstrated strong fear conditioning to snakes in humans and fast nonconscious processing of snake images; these are mediated by a fear network in the human brain involving the amygdala. A 2013 study provided neurobiological evidence in primates of natural selection for detecting snakes rapidly.
In fiction
In non-medical press and literature, the movie-character Indiana Jones has been used as an example of someone with ophidiophobia, or just fear of snakes.
