In 1909, Sigmund Freud published a case study of a four-year-old boy known by the pseudonym, “Little Hans,” who was extremely afraid of horses. Many years later, it was revealed that Little Hans actually had been Herbert Graf — the son of Max Graf, a musical scholar from Vienna, Austria (Goleman, 1990). Herbert became so afraid of horses that he would not leave his family's house. Herbert's father described the boy’s problems in a letter he sent to Freud:

during the last few days [Little Hans] has developed a nervous disorder, which has made my wife and me most uneasy, because we have not been able to find any means of dissipating it. ... He is afraid that a horse will bite him in the street” (quoted in Spitzer, et al., 1994, p. 517).

According to his parents, Herbert's fear first emerged while walking down a city street with his mother. He saw a large horse fall down and begin to kick violently. Herbert developed a phobia, which is a persistent and irrational fear of an object, situation, or activity, that is so severe that it causes significant difficulties in daily functioning. To be considered "irrational," the amount of fear must be much greater than is warranted by the actual danger posed by the feared event. For example, a man who refuses to go into basements because there are spiders "down there," might be suffering from a phobia (unless, of course, large numbers of highly poisonous spiders are found frequently in basements in his area). Furthermore, except in cases of young children, the person experiencing the fear must realize to some extent that the amount of fear is unwarranted given the actual danger. (If the person thinks that his or her irrational fear actually is rational and warranted, we would conclude that the person is suffering from a delusion[∂].) The extent of Herbert's fear seemed unwarranted and it definitely interfered with his daily functioning (he refused to leave the house).

Freud concluded that the development of Herbert's phobic fear was due to the interplay of conscious and unconscious thought and desires in conflict with one another. But is it possible to explain its development with classical conditioning? Yes, it is (see Figure 1). Herbert first became afraid of horses after seeing and hearing a large horse fall and kick violently. In the terminology of classical conditioning, the sight and sound of a horse is a conditioned stimulus (CS). The sight and sound of a large horse falling and then violently struggling to get up, as well as the commotion that this would have caused among people nearby, would have been sufficient to frighten any child (that is, no learning would have been needed). Thus, the sight and sounds of the tumultuous situation surrounding the fallen horse was, for Herbert, an unconditioned stimulus (UCS). The reflexive distress automatically elicited by this frightening situation was an unconditioned response (UCR); and the learned distress automatically elicited by the sight of horses was the conditioned response (CR). The acquisition of the CR, according to this classical-conditioning explanation, was due to the formation of a CS-UCS association after the two sets of stimuli were paired during Herbert's walk with his mother.

Figure 1. Classical conditioning terminology as applied to the the case of "Little Hans"

Thus, it is possible to explain Freud's famous case as an instance of classical conditioning. Of course, we cannot know for certain that this was the primary cause of Herbert's phobic fear of horses, but the explanation seems quite plausible.

You've already been introduced to the behaviorist, John Watson, several times. Watson (1916) proposed that mental disorders such as phobias might be learned, and that this learning could occur through (what now is called) classical conditioning. A few years later, Watson and Rayner (1920) put this proposal to the test. They argued that Freud's theory, which states that phobias are primarily the result of unconscious mental conflicts (especially conflicts involving sexuality), is inferior to the behavioristic theory that classical conditioning causes phobias:

It is probable that many of the phobias in psychopathology [the scientific study of mental disorders] are true conditioned emotional reactions.... Emotional disturbances in adults cannot be traced back to sex alone. They must be retraced along at least three collateral lines — to [conditioned responses] set up in infancy and early youth in all three of the fundamental human emotions. (p. 14)

The "three fundamental emotions" referred to are fear, rage, and love: Watson and Rayner believed that conditioned responses developed during the early years of life derive from unconditioned responses involving these three emotions.

One reason that Watson and Rayner (1920) concluded that the psychoanalytic theory of phobias was inferior to their theory is that the psychoanalytic theory needed to make more assumptions than did the classical-conditioning theory. Theories derived from the Freudian version of the psychoanalytic approach tend to be very complicated and, since you have not yet learned much about this approach, I present at the end of this section (for anyone who might be interested) six assumptions that, by my count, are needed to explain the development of phobias according to the Freudian explanation. The behavioristic approach, on the other hand, requires (again, by my count) only three assumptions:

• humans develop associations between stimuli when they are paired closely in time;
• the physical nature of this association involves the development of new CNS connections;
• the new CNS connections cause organisms to respond reflexively to previously neutral stimuli.

When comparing two or more theories, all of which are able to explain something equally well, scientists generally consider the theory requiring the fewest assumptions to be the best. Assumptions are untested claims and, hence, the likelihood that they are correct is more questionable than is the case for tested claims. The greater the number of assumptions contained in a theory, the greater is the probability that at least one of them will be wrong and, hence, the greater the likelihood that the theory is incorrect.

According to the rule of simplicity, when two theories both explain something equally well, the theory that makes the fewest assumptions is preferred. The rule of simplicity (supposedly) was summed up by Albert Einstein, who reportedly said: "Everything should be made as simple as possible, but not simpler" (quoted in Gibbs & Hiroshi, 1997). Watters & Ofhse (1999) provided another way to think of the rule of simplicity: "When you hear hooves, think horses, not zebras" (p. 222). If a teacher knows only that a student looks like she is sleeping during class and wishes to explain why this is so, he should, according to the rule of simplicity, accept the explanation that makes the fewest assumptions. The following explanation has only two assumptions:

• the student is asleep;
• the student is sleeping because she is tired.

It would be much more reasonable for the teacher to accept this explanation than the following, which makes five assumptions:

• the student is only pretending to be asleep;
• the student is pretending to be asleep because she wants the teacher to conclude incorrectly that she is asleep;
• the student wants the teacher to conclude incorrectly that she is asleep because she thinks that, if the teacher does so, he will infer that he is boring;
• the student thinks that, if the teacher infers that he is boring, he will feel bad about himself;
• the student wants the teacher to feel bad about himself.

Although it is possible that this second explanation is true, it seems unreasonable to conclude that it is likely to be true: there is a greater chance that at least one of its assumptions is incorrect.

The large number of untested (and often untestable) assumptions in Freud's theories have bothered many people since Watson and Rayner (1920) made their criticisms. You will learn more about Freud and psychoanalysis in Section X [X stands for unknown: I have not placed this section on the web site yet].

Study Questions for Section 5-8

1. How would you define a phobia in your own words?
2. What are some examples of phobias you are aware of?
3. How can the development of Little Hans's horse phobia be explained with classical conditioning? (NOTE: In answering this question, try not to look at the description or the figure presented above: try to answer from memory.)
4. How can the development of the other phobias listed in your answer to #2 be explained with classical conditioning? (NOTE: In the case of these examples, you may need to "make up" ways that the phobias could have been learned.)
5. According to Watson and Rayner (1920), what advantage would the classical-conditioning explanation of Little Hans's horse phobia have over the psychoanalytic theory?
6. How would you define the rule of simplicity in your own words?
7. We try to explain things all the time in our everyday lives (such as why our car doesn't start one morning). What is an example of your use of the rule of simplicity in your everyday life? Did your use of the rule of simplicity help you to find the correct explanation?
8. How might the rule of simplicity mislead us when trying to explain a phenomenon? (NOTE: I did not provide an answer to this above: you'll need to think carefully about possible problems with using the rule of simplicity.)

Go to Quiz 5-8 questions

Go to Readings Section 5-9

Accordng to Freudian psychoanalysis, there probably are more assumptions required than the six listed below. In addition, please be aware that I am not a Freudian scholar and, hence, I present the list with much humility and with the realization that such scholars might find significant problems with the specific assumptions contained therein:

• humans inherit memories of traumatic events experienced by our ancestors;
• trivial early-childhood experiences have large influences because they activate these memories;
• these influences involve an active unconscious mind that is the primary determinant of personality;
• repression occurs because of conflicts between biological motives linked to these inherited memories and constraints on the satisfaction of these motives;
• the ego must use energy to keep these repressed conflicts at the unconscious level;
• the repressed conflicts are expressed in abnormal behaviors;
• and so on