Freud, Sigmund (1856-1939), Austrian physician, neurologist, and founder of psychoanalysis

 In the late 19th century Viennese neurologist Sigmund Freud developed a theory of personality and a system of psychotherapy known as psychoanalysis. According to this theory, people are strongly influenced by unconscious forces, including innate sexual and aggressive drives.

 Sigmund Freud tried to make a solid science of human behavior. “Have you not noticed,” he wrote early in the century, “that every philosopher, every imaginative writer, every historian and every biographer makes up his own psychology for himself, brings forward his own particular hypotheses concerning the interconnections and aims of mental acts – all more or less plausible and all equally untrustworthy? There is an evident lack of any common foundation.” Freud tried to establish a foundations solid as the foundations in physics and chemistry.

 Freud worked by introspection, which is looking from the outside inward. For Freud the brain was a black box. When he spoke about the unconscious workings of the mental apparatus, he added a warning for his readers: “I must beg of you no to ask what material it is constructed of. That is not a subject of psychological interest. Psychology can be as indifferent to it as, for instance, optics can be to the question of whether the walls of a telescope are made of metal or cardboard.” “We must recollect,” Freud once admonished his followers, “that all our provisional ideas in psychology will presumably one day be based on an organic substructure.” But Freudians and virtually of the schismatic sects that split away from the Freudians studied the psyche strictly from the top down and the outside in. One psychologist wrote that as far as he was concerned the skull could be full of cotton.

 Freud and his followers argued that an individual’s problems are determined more by experience than by wiring as did the behaviorists.

 -         Weiner


John B. Watson (1878-1958)

Psychologist, born in Greenville, SC. He studied at Chicago, and became professor of psychology at Johns Hopkins University (1908-20), where he established an animal research laboratory. He became known for his behaviorist approach, which he later applied to human behavior. In 1921 he entered advertising, and wrote several general books on psychology.

- Abandoned introspection and the abstract study of consciousness

- Studied psychology from a functionalist perspective, which gave rise to behaviorism

- Viewed behavior holistically: not simply a function of 'consciousness', nor just physiological events

- Felt we could control human behavior as an engineer controls a machine

- Developed a way of assessing the suitability of military candidates for World War I

- Used stimulus-response analysis

- Mapped out the major categories of behavior: explicit and implicit, hereditary (emotions and instincts) and acquired.


Clark Hull (1884 – 1952)

Clark Hull grew up handicapped and contracted polio at the age of 24, yet he became one of the great contributors to psychology. His family was not well off so his education had to be stopped at times. Clark earned extra money through teaching. Originally Clark aspired to be a great engineer, but that was before he fell in love with psychology. By the age of 29 he graduated from Michigan University. When Clark was 34 when he received his Ph.D. in Psychology at the University of Wisconsin in 1918. Soon after graduation he became a member of the faculty at the University of Wisconsin, where he served for 10 years. His life long emphasis was on the development of objective methods for psychological studies designed to determine the underlying principles of behavior.

Hull devoted the next 10 years to the study of hypnosis and suggestibility, and in 1933 he published Hypnosis and Suggestibility, while employed as a research professor at Yale University. This is where he developed his major contribution; an elaborate theory of behavior based on Pavlov's laws of conditioning. Pavlov provoked Hull to become greatly interested in the problem of conditioned reflexes and learning. In 1943 Hull published, Principles of Behavior, which presented a number of constructs in a detailed Theory of Behavior. He soon became one of the most cited psychologists.

Hull believed that human behavior is a result of the constant interaction between the organism and its environment. The environment provides the stimuli and the organism responds, all of which is observable. Yet there is a component that is not observable, the change or adaptation that the organism needs to make in order to survive within it's environment. Hull explains, "when survival is in jeopardy, the organism is in a state of need (when the biological requirements for survival are not being met) so the organism behaves in a fashion to reduce that need" ( Schultz & Schultz, 1987, p 238). Simply, the organism behaves in such a way that reinforces the optimal biological conditions that are required for survival.

Hull was an objective behaviorist. He never considered the conscious, or any mentalistic notion. He tried to reduce every concept to physical terms. He viewed human behavior as mechanical, automatic and cyclical, which could be reduced to the terms of physics. Obviously, he thought in terms of mathematics, and felt that behavior should be expressed according to these terms. "Psychologist must not only develop a thorough understanding of mathematics, they must think in mathematics" (Schultz & Schultz, 1987, p 239). In Hull's time three specific methods were commonly used by researchers; observation, systematic controlled observation, and experimental testing of the hypothesis. Hull believed that an additional method was needed, - The Hypothetico Deductive method. This involves deriving postulates from which experimentally testable conclusions could be deduced. These conclusions would then be experimentally tested.

Hull viewed the drive as a stimulus, arising from a tissue need, which in turn stimulates behavior. The strength of the drive is determined upon the length of the deprivation, or the intensity / strength of the resulting behavior. He believed the drive to be non-specific, which means that the drive does not direct behavior rather it functions to energize it. In addition this drive reduction is the reinforcement. Hull recognized that organisms were motivated by other forces, secondary reinforcements. " This means that previously neutral stimuli may assume drive characteristics because they are capable of eliciting responses that are similar to those aroused by the original need state or primary drive" (Schultz & Schultz, 1987, p 240). So learning must be taking place within the organism.

Hull's learning theory focuses mainly on the principle of reinforcement; when a S-R relationship is followed by a reduction of the need, the probability increases that in future similar situations the same stimulus will create the same prior response. Reinforcement can be defined in terms of reduction of a primary need. Just as Hull believed that there were secondary drives, he also felt that there were secondary reinforcements - " If the intensity of the stimulus is reduced as the result of a secondary or learned drive, it will act as a secondary reinforcement" ( Schultz & Schultz, 1987, p 241). The way to strengthen the S-R response is to increase the number of reinforcements, habit strength.

Clark Hull's Mathematico Deductive Theory of Behavior relied on the belief that the link between the S-R relationship could be anything that might effect how an organism responds; learning, fatigue, disease, injury, motivation, etc. He labeled this relationship as "E", a reaction potential, or as sEr. Clark goal was to make a science out of all of these intervening factors. He classified his formula

sEr = (sHr x D x K x V) - (sIr + Ir) +/- sOr

as the Global Theory of Behavior. Habit strength, sHr, is determined by the number of reinforces. Drive strength, D, is measured by the hours of deprivation of a need. K, is the incentive value of a stimulus, and V is a measure of the connectiveness. Inhibitory strength, sIr, is the number of non reinforces. Reactive inhibition, Ir, is when the organism has to work hard for a reward and becomes fatigued. The last variable in his formula is sOr, which accounts for random error.
Hull believed that this formula could account for all behavior, and that it would generate more accurate empirical data, which would eliminate all ineffective introspective methods within the laboratory (Thomson, 1968).

Although Hull was a great contributor to psychology, his theory was criticized for the lack of generalizability due to the way he defined his variables in such precise quantitative terms. "Thus, Hull's adherence to a mathematical and formal system of theory building is open to both praise and criticism" (Schultz & Schultz, 1987, p 242).


Skinner, B(urrhus) F(rederic) (1904-1990)

American psychologist B. F. Skinner became famous for his pioneering research on learning and behavior. During his 60-year career, Skinner discovered important principles of operant conditioning, a type of learning that involves reinforcement and punishment. A strict behaviorist, Skinner believed that operant conditioning could explain even the most complex of human behaviors.

Operant Behavior = ordinary behavior, it looks free but the controls are hidden in the consequences. It seems to be uncaused because the behavior has a prior history of reinforcement. Operant behavior is shaped. The cause for operant behavior is a history of shaping.

Shaping = differential reinforcement for successive approximations that have been generated by extinction induced variability.

Successive Approximations = behavior that successively (1 after another) approximates (gets closer and closer) to one goal.

Differential Reinforcement = reinforcing some behaviors and not others.

Reinforcement = Strengthen (not reward).

You reinforce approximations closer to what you want. Prior behaviors are no longer reinforced and put through extinction. Your behavior evolves in response to the environment. A response if affected by its consequences – actually a biological response to the consequences. New behavior comes from extinction of old behavior.

Properties of an operant: The modifiability of the response with changes in consequences. Therefore, to show a behavior is an operant, you must show that it is modifiable. Behavior conforms to contingencies; the response comes to conform.

Three Classes of Behavior:

1.     Operant Behavior: A class of responses which produce a common effect on the environment. The frequency of occurrence of members of the class are subject to modification such that there will develop an increased  correlation/correspondence between members of the response class (producing a particular outcome) and the frequency of these members.

2.     Reflex: Unlearned correlation between a class of stimuli and a class of responses. It’s not a stimulus alone, nor a response alone. Also, it’s a correlation between a group of stimuli and responses, e.g. different types of pepper = sneezing.

3.     Classical Conditioning: (conditional reflex) correlate a neutral stimulus with an unconditioned stimulus to create a conditioned reflex. Ex. You pair (correlate) a bell with food. Bell will elicit response that food did, i.e. salivation.