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What Are You So Afraid Of?

More than half of us have an unreasonable fear. We're still learning why.

Ask almost anyone you meet and they’ll claim they have a phobia of some kind—whether a simple common fear, like fear of spiders, or a seemingly irrational fear, such as a fear of buttons, or even wool.

While phobias are common, it is far from clear where they come from and what causes them—even to the sufferer. Specific phobias are defined as a “marked fear or anxiety about a specific object or situation"—flying, heights, animals, receiving an injection, or seeing blood, for example.

Phobias are extraordinarily common, with surveys suggesting that a clear majority of the general population (60.2%) experience “unreasonable fears.” There is also a clear gender difference in the prevalence of specific phobias, with women twice as likely as men to be diagnosed.

The phobic trigger typically elicits extreme fear and often panic in the sufferer, which usually means that he or she develops avoidance strategies designed to minimize the possibility of contact with the trigger.

People are normally aware that their fear is excessive or unreasonable, but they do acquire a strong set of phobic beliefs that appear to control their fear. These beliefs normally contain information about why they think the phobia is threatening and how to react when they are in the phobic situation—"The spider will get onto parts of me I cannot reach”; "When I encounter a spider, I’ll scream and panic.” Many contemporary psychological treatments for specific phobias are designed to challenge these dysfunctional phobic beliefs and replace them with more functional beliefs that foster approach and contact with the phobic stimulus instead of avoidance. These types of treatment are usually highly successful and often take as little as one session to achieve their success.

Interestingly, common phobias tend to focus on a relatively small group of objects and situations—animal phobias (snakes, spiders, rats, mice, cockroaches, maggots, etc.); social phobia; dental phobia; water phobia; height phobia; claustrophobia; and a cluster of blood, injury, and inoculation fears (known as BII). Most other types of phobias are less common, and can be thought of as quite unusual given the degree of threat they might realistically pose—fear of cotton wool, buttons, chocolate, dolls, or vegetables, to name a few.

There are some important cultural differences in the kinds of stimuli and events that can become the focus of clinical phobias. For example, Taijin-kyofu-sho (TKS), a common Japanese syndrome characterized by a fear of embarrassing or offending other people, is rather different from the Western syndrome of social phobia, in which the fear is based on the public embarrassment experienced by the phobic individual himself or herself. We have also found a number of important cross-cultural differences in animal fears. For example, while fear of spiders is a common phobic reaction in most Western cultures, spiders were significantly less feared in a comparable population sample from India. This kind of cross-cultural variability suggests that "fear-relevance" may be at least in part determined by factors specific to individual cultures.

What causes phobias?

Attempts to explain specific phobias date back to the early days of the psychoanalytic approaches pioneered by Freud, and the conditioning views developed by the behaviorist J.B. Watson. Originally, there was a tendency to try and explain all types of phobias with just one explanatory theory, but this approach has now given way to the view that different types of phobias might be acquired in quite different ways.

Classical Conditioning and Phobias. Attempts to explain phobias in terms of good old Pavlovian classical conditioning date back to the famous “Little Albert” study reported by Watson & Rayner in 1920. Albert was an 11-month old infant, and Watson & Rayner attempted to condition in him a fear of his pet white rat. They did this by pairing the rat with the frightening event of a loud noise produced by striking an iron bar, which distressed Little Albert (today this would be a highly unethical study!). After several pairings of the rat with the noise, Albert began to cry whenever the rat was introduced into the room. It is probably not the case that all phobias result from traumatic conditioning episodes, but there is strong evidence that traumatic conditioning experiences are responsible for the acquisition of at least some, such as dental phobia, choking phobia, accident phobia, and most dog phobias.

The fact that phobias tend to be focused on a limited set of fears that have evolutionary significance has led some researchers to suggest that we may be biologically pre-wired to acquire certain phobias. In 1971, Martin Seligman argued that evolutionary selection pressures have evolved in us a biological predisposition to learn to associate fear with stimuli that were life-threatening for our pre-technological ancestors and have been present for many centuries. That is, we tend to have a built-in predisposition to learn to fear things such as snakes, spiders, heights, and water because these were life-threatening to our ancestors. Our ancestors who evolved a biological predisposition to fear these kinds of stimuli would have been more likely to survive, and to pass that fear predisposition on to future generations. In contrast, we rarely develop clinical phobias of life-threatening stimuli that have only appeared more recently in our phylogenetic past—such as guns and electricity.

Nevertheless, while evolutionary accounts are appealing and appear to have at least some validity, we must be cautious about accepting them on the basis of existing evidence. First, such accounts depend on the fact that current phobic stimuli have actually acted as important selection pressures over our evolutionary past. But this is very difficult to verify. Do we really tend to have phobic reactions to spiders because they constituted an important life-threatening pressure on our pre-technological ancestors? There is no convincing evidence to suggest this, since only a mere 35 of the 35,000 species of spiders on the planet today are genuinely life-threatening. Second, evolutionary accounts can be constructed in a post hoc manner and are at risk of being either “adaptive stories” or “imaginative reconstructions." This view argues that it is possible to construct, post hoc, an adaptive scenario for the fear and avoidance of almost any stimulus or event.

This does not mean that evolutionary accounts are wrong, merely that they are tantalizingly easy to propose, though very difficult to substantiate. (You might find this blog useful and informative on this question.)

Multiple Pathways. There is no reason why the acquisition of all phobias should be explained by a single process—and evidence is now accumulating to suggest that different types of phobias are acquired in quite different ways. I have already suggested that some phobias are caused by traumatic conditioning experiences. Many other common phobias do not appear to be characterized by a traumatic experience at their outset—in fact, sufferers often cannot recall the exact onset of a phobia, which suggests that it may be gradual and precipitated by factors that are not immediately obvious. Phobias that fit this description include most animal phobias, as well as height and water phobia.

Recent evidence suggests that at least some phobias are closely associated with the emotion of disgust. High levels of disgust sensitivity have been found to be associated with small animal phobias in general—spider phobia specifically—and has been hypothesized to play a role in blood/injury/injection phobias as well as contamination fears. Disgust is a food-rejection emotion whose purpose is to prevent the transmission of illness and disease through the oral incorporation of contaminated items. Elevated disgust sensitivity implies increased avoidance of disgust-relevant objects (feces, mucus, etc.).

In the case of animal phobias, I have argued that many animals become the focus for phobic response because they have disgust relevance. Specifically, they may have acquired a disgust relevance by directly spreading disease and being a source of contamination (rats, cockroaches); by possessing features which mimic primary disgust relevant stimuli (resembling, for example, feces or mucus, like slugs, or animal that are perceived as slimy, such as snakes, snails or lizards); or by having contemporary or historical significance as stimuli that signaled disease, illness or contamination (maggots, spiders). This disease-avoidance model of animal phobias is supported by findings that high levels of disgust sensitivity is a vulnerability factor for animal phobias such as spider phobia, and can mitigate against successful therapy if it is not directly addressed in treatment.

Alternatively, there is evidence that factors closely associated with panic and panic disorder are also linked to a number of specific phobias. First, there is a fairly high comorbidity rate between panic disorder and specific phobias, suggesting that panic is common in people suffering from many different types of specific phobia. Second, some categories of specific phobia share important characteristics in common with panic disorder. For example, height phobia and claustrophobia appear to have a preponderance of spontaneous onsets typical of panic disorder; have a high rate of co-occurrence with panic disorder; and frequently involve uncontrollable panic attacks as one of the symptoms of phobic response. Interestingly, height phobia is associated not only with heightened discrimination of bodily sensations, but also with a bias toward interpreting ambiguous bodily sensations as threatening—a characteristic central to panic disorder itself.

These examples suggest that specific phobias may have a number of different causes involving quite different vulnerability factors and psychological processes. This being so, specific phobias are a coherent category only on the basis of their defining symptoms. Therapists may need to look more closely at the different causes to construct successful treatments.

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