Pavlovian conditioning is basic to learning and is obviously a critical factor in the acquisition of phobias. This model assumes that all members of a species share a common set of reflexes, hard-wired responses to certain stimuli. These unconditional reflexes are critical to survival. Pavlovian conditioning, which relies on these reflexes, or the stimulus-response relationship, has been shown to be fundamental to learning such that all animals learn to adapt to their environment based on this concept.
The traditional learning model, based on animal conditioning research, has been extraordinarily useful but unfortunately very limited where phobias are concerned (McNally 284). First of all, one cannot assume that human phobias are the same as fears conditioned in animals in a laboratory, and they are not, as will be discussed later.
Field and Davey also had the following problems with the traditional model (191-192). Phobias, for one, tend to be highly resistant to extinction, more so than other acquired responses. Some phobics have no memory of an aversive conditioning event at the onset of their phobia while others recall an associated traumatic event. Some persons become more phobic with successive presentations of the conditioned stimulus, even when this stimulus is unreinforced by an aversive conditioned response. Furthermore, not everybody who undergoes a traumatic experience will develop a phobia.
In addition, while the Pavlovian model views all stimuli as being equivalent in their ability to create an association with a negative consequence, phobias should be uniformly distributed across a broad range of experiences (Field and Davey 192). It is obvious, however, that this is not the case, since some fears are more common than others.
While most Americans, for example, live in an urban environment, they are more fearful (in both intensity and frequency) of insects, reptiles, heights, and storms than guns, cars, and stoves, even though nonbiological stimuli have a much higher likelihood of being associated with an aversive consequence. Also, human phobias of animals tend to be developed at younger ages, when they are still vulnerable to predators.
Thorpe and Salkovskis have noted other pathways to fear besides the Pavlovian model of direct acquisition through conditioning: (1) indirect acquisition, for example, by observing phobic people, and (2) acquiring fear-inducing information, from reading car crash statistics, for instance (81-83). So other factors must be at work besides direct Pavlovian conditioning if we are to explain these variations.
Coming from an evolutionary point of view, Seligman proposed a theory wherein an organism evolves a predisposition, or preparedness, to learn certain associations that are important for survival (406). These are instances of “prepared learning.” Associations that are irrelevant to survival are “unprepared” and associations that are detrimental to survival are “contra-prepared.”
Seligman’s theory of preparedness was meant to explain the inconsistencies about phobias seen in the traditional behavioral model of learning. Seligman noted four characteristics of phobias that differentiate them from fears conditioned in the laboratory: “(a) ease of acquisition, (b) irrationality, (c) belongingness, and (d) high resistance to extinction” (qtd. in McNally 295).
Ease of acquisition refers to the number of trial repetitions required to elicit a fearful response from the stimulus. In the case of phobias, a single trial can be sufficient and often is. Irrationality, or noncognitiveness, refers to the fact that a phobic will continue to be fearful in the presence of the object of fear even after it is clear that no threat exists. Belongingness is the quality a person recognizes when realizing that a stimulus and response are paired, such as the object of a phobia and the threat it posed in prehistoric times. A high resistance to extinction is even today the hallmark of a phobia. It is, indeed, one of the most challenging aspects of phobias.
Mineka has been a strong supporter of preparedness theory (199). It had been thought that monkeys were innately fearful of snakes; however, Mineka demonstrated that when first exposed to a snake, a lab-reared monkey will show no fear. It will, however, demonstrate fear if the mother is present upon first exposure; that is, it learns to be afraid by observation of its mother. But this behavior did not carry through to nonfrightening situations and remained specific to biological stimuli. It was concluded that the potency and rapidity of observational learning in association is due to the evolutionary significance of the biological stimuli (Mineka 239-240).
But what of differences between individuals? The Pavlovian model assumes that inborn reflexes are shared by all members of a species. Öhman and Mineka believe that humans are genetically predisposed with the ability to associate fear with stimuli that threatened the survival of our earliest ancestors (6). Since this is a genetic mechanism, and there are genetic differences among humans, some people will be more or less fearful than others, depending on the situation. Öhman believes that “although humans are in general prepared to acquire fears of ancestral dangers easily, some individuals must be more prepared than others to acquire specific fears. These super-prepared humans are, he proposes, vulnerable to phobias” (qtd. in Ledoux 229).
Snakes were found to be among the most prevalent of human phobias, with close to 40% of females and 12% of males in New England reporting an intense fear of them. The authors noted the fact that primates, the animals closest to us on the evolutionary scale, also commonly fear snakes, although captive primates were consistently less fearful than primates in the wild. These observations are strongly consistent with the evolutionary role for fear. The adaptive nature of this fear is reinforced by the fact that large snakes regularly attack primates in the wild.
Mineka and Öhman recently proposed the concept of a “fear module,” a behavioral module with the following four main characteristics: selectivity of input (the central tenet of preparedness theory), automatic activation, encapsulation (where a learner’s cognitive skills are focused in some areas and not others), and a dedicated neural apparatus (931-933). The appeal of this concept is that it is allows for the neurobiological point of view of fear conditioning.
Mineka and Öhman also proposed two levels of learning in fear conditioning, based on learning through ontogeny and phylogeny (928). There is a basic associative level of learning, evidenced by automatic emotional responses, controlled by the amygdala. Then there is the cognitive level of contingency learning, controlled by the hippocampus. Fear learning in human conditioning with fear-relevant stimuli activates both levels, but fear learning with fear-irrelevant stimuli tends to occur only at the cognitive level, unemotionally.
It is important therefore to note that fears created in the laboratory in response to survival-irrelevant stimuli (e.g., auditory cues such as buzzers) involve unprepared learning and therefore offer a poor framework within which to conduct experiments on human phobias.
Neuroscience looks at phobias from the point of view of “neural circuitry,” more specifically the amygdala and a variety of complex hormones, and this has been written up extensively in the literature. But even in the face of such technologically advanced research, the theory of biological preparedness still plays a role. It has been shown that conditioning to fear-relevant stimuli, including angry facial expressions, is less resistant to extinction than other conditioning to neutral stimuli and can even be acquired through visual masking techniques (LaBar and Cabeza 55).
But with the rise of cognitivism, the theory of preparedness fell into disfavor with some. Lovibond, Siddle, and Bond proposed an alternative theory to explain resistance to extinction: selective sensitization, where a pre-existing response tendency is activated by a perceived threat (449). This phenomenon explains why “many phobic disorders arise when the fear-relevant situation is experienced after a traumatic or stressful event, rather than before it, as required by conditioning theories” (Lovibond, Siddle, and Bond 452).
Gray and McNaughton noted in particular how the skin’s conductance response is also associated with the orienting reflex, which can tarnish the results of preparedness studies, since most use the skin’s galvanic response to gauge the degree of fear (306-312).
Harris even went so far as to state a number of interpretive problems with Watson and Raynor’s famous conditioning of Little Albert (151-158) and Field and Davey pointed out the phenomenon of rumination influencing the perceived future threat of a fear-related stimulus (197).
When McNally conducted an extensive review of the research on phobias to see how well preparedness theory stood up, he found no evidence that acquisition was any faster and had problems supporting the view that there was lack of rationality (295). He did, however, find much evidence demonstrating that extinction is slower for prepared learning (McNally 292).
Perkins attacked Seligman’s archetypal yawning dog by showing that dogs can indeed be conditioned to yawn, even though it is a contraprepared learning task (138-144). The author even stated, “It is proposed to limit Preparedness Theory to physiological preparedness, and that psychological preparedness either be revised (to exclude dogs yawning on cue) or abandoned” (Perkins 138).
One problem with preparedness theory is that it involves a circular definition. We define preparedness in terms of the ability to learn quickly because of a biological predisposition. However, how can we then tell if there is a biological predisposition? Because of the ability to learn quickly? This lack of underlying theory is one of the criticisms the cognitive psychologists have and it will hopefully be addressed eventually.
But despite this, preparedness theory has held up well through the decades and today enjoys its status among even the most sophisticated conditioning models, which tend to be a mix of behavioral and cognitive theories. And theories, if they are to survive, must change and adapt; even if Seligman’s original statement of preparedness theory was lacking in areas, it has benefited greatly from new research. In response to criticism from the cognitivists, the theory evolved and can now explain many of the problems that were pointed out in the earlier literature.
It should be mentioned that the field of psychology has evolved and branched out to the point where only a melting pot of specialized theories, from traditional behaviorism to the most advanced neuroscience, can hope to explain the complexities of the mind.