The History and Bases of
The goal of this chapter is provide an overall view, a "big picture" framework, for the introductory level study of psychology. Such a "big picture" framework is not only beneficial but also very necessary owing to the diversity of scientific interests within Psychology. Otherwise, the width of psychology's scope might lead you to utter, as an old saying goes, you can't see the forest for the trees. Psychology has grown dramatically in its range of interests since its founding, incorporating the natural and social sciences as well as the liberal arts and humanities. Because of the great breadth and depth of psychology, this text, as any other Introductory Psychology text, will not be able to do delve in-depth in all aspects of the field. Every topic covered will be simplified and some topics will, unfortunately, be omitted. However, the hope is that the "big picture" of modern psychology will emerge, nonetheless.
I. Psychology and its
relationship to other fields.
Psychology is the study of the mind and how its processes guide and direct our thoughts, actions and perceptions. But it is a relatively young formal science with the first psychology laboratory being opened in 1879 by Wilhelm Wundt at the University of Leipzig in Germany. However, the roots of psychology go back thousands of years to the early Greeks. Those roots are very closely tied to biology and philosophy; and in particular the subfields of physiology (the study of the functions of living things) and epistemology (the study knowledge and how we know what we know), respectively. In fact, before Wundt's laboratory, researchers studying what we today would call psychology were frequently based in the departments of philosophy in universities. The ties to physiology and epistemology are so close that we can think of psychology as the hybrid offspring of those two parent fields of study.
Today, because of that hybrid heritage, psychology is not only considered one of the social sciences (alongside sociology, economics, political science and cultural anthropology), but an ally to the natural sciences (biology, chemistry, physics and mathematics) and humanities (philosophy, languages, music and art). Many psychologists collaborate on research and other projects with scholars and scientists in those different fields adding to the diversity of interests which can fall under the umbrella of a modern psychology department. For instance, one psychologist may work with an economist to understand how people estimate the risks and potential benefits of various investments or business enterprises and allocate their resources. Another psychologist might collaborate with a neuroscientist or a biochemist to investigate the behavioral and psychological changes brought about by a brain injury or the administration of a drug. Yet another psychologist may join with a music or art scholar to study the mental processes which underlie creativity. All three would be psychologists but their work would span completely different areas of expertise.
II. Psychology: In general
As noted, the roots of psychology are ancient and extended though history to the more modern disciplines of physiology and philosophy. However, the distinction between modern psychology and its ancient and even its relatively recent predecessors has to do primarily with the methods and techniques employed.
As far as the distant past of psychological interests is concerned, the physicians of ancient Egypt were aware of the symptoms of brain damage. It was evident that the brain had something to do with behavior and actions from antiquity because ancient warfare was a very brutal and gory enterprise. The use of heavy metallic cutting weapons (swords spears, axes) could, in the event of a blow to the head, cause visually obvious damage to the brain, often deadly but sometimes merely crippling. However, despite their experience, the Egyptians believed that the heart was the seat of consciousness. No doubt their belief was influenced by the observation that during emotionally charged experiences, which are often deeply psychologically moving and especially memorable, it often seems that all we can hear in our heads is the heart's pounding. The ancient Greeks were divided on that question. The philosopher Aristotle, for instance, believed that the heart was the seat of the mind and that the brain was merely a radiator for the blood to dissipate the heat generated by the heart. In contrast, the philosopher and physician Hippocrates (the father of Western medicine) proposed that the brain was the seat of the sensations (being the site of the eyes, ears, nose and tongue) as well as the center of the intellect, based in part on the accumulated knowledge acquired from dissections and battlefield injuries. For instance, the eyes, being necessary for visual experience of the world, are not connected to the heart but send a nerve to the brain.
After the rise of the Romans, the Greek physician, Galen, combined what he learned from animal dissections as well treating the injuries of gladiators to form his views of brain function. Galen somehow accurately came to the conclusion that the front-most part of the brain, the cerebrum, was involved in sensations and memories and a structure near the back, the cerebellum, was involved in making movements. However, his guesses fell short when he formed his opinion of the role of the fluid-filled spaces within the brain called ventricles which he believed caused fluids to move via the nerves (which he thought were hollow tubes) between the brain and the muscles and sense organs to cause movements or transfer sensations. Galen's view was dominant for about 1500 years, even after the fall of the Roman Empire and throughout the Dark Ages until the Renaissance.
With the fall of the Roman empire, the progress in the physiological and philosophical bases of psychology came to a halt as the accumulated knowledge and views of the ancient Greeks and Romans were limited to the libraries in the few institutions of learning that endured, primarily in the monasteries and universities associated with Roman Catholic church as Europe struggled through the Dark Ages. Further progress would not be made until the Renaissance and the invention of the printing press which allowed for widespread duplication of copies of those ancient philosophical and medical manuscripts which survived.
As Europe emerged from the Dark Ages and the works of Galen and other ancient scientists and philosophers were rediscovered, throughout the Renaissance, the dominant view of the role of the brain in controlling the body was based on hydraulics and the movement of fluids though the brain, nerves, muscles, and sense organs, following the views of Galen. However, during experiments with static electricity in the 1780's, Luigi Galvani found that electric charges applied to nerves or muscles could cause the limbs of frogs to twitch, even after they were dissected. Galvani proposed that animal electricity was the basis of movement and even life, itself. Galvani's nephew, Giovanni Aldini, a scientist in his own right, even performed public demonstrations of the phenomenon, termed galvanism, with animal carcasses and the bodies of executed criminals. As a bit of historical trivia, such experiments and demonstrations were partial inspirations for Mary Shelly's book, Frankenstein, published in 1818.
Along another line of discovery, in the mid-1600's, Anton van Leeuwenhoek, after improving the primitive microscope-like devices used by cloth merchants to examine the quality of fabrics, began to publish works on the microscopic examination of living things, being credited with the discovery of bacteria in 1676. In the field of biology, the use of microscopes eventually led to the understanding that all living things, even complex animals are made of cells. By the late 1700's and early 1800's, physiologists had begun to be interested in how the cells of the sensory organs, which under microscopic examination appeared similar to cells from other organs, were apparently uniquely able to give rise to our experience of the world. In the early1800's, Johannes Muller, one of the most important physiologists of his time, had begun to study nervous system action and sensory mechanisms and guided this early field which would eventually become psychophysics, the study of the relationship between the intensity of a physical stimulus and the subjective psychological perception that stimulus. Muller was responsible for the Doctrine of Specific Nerve Energies which states that the sensation following the stimulation of a sensory nerve does not depend on the nature of the stimulation, but upon the nature of the sense organ. For instance, the firing of the optic due to mechanical pressure would not be perceived as the sensation of touch but as some sort of visual stimulus like spots or flashes of light. Not only did his laboratory advance early psychophysics, but he mentored and trained many of the most successful and noted psychophysicists that followed after him, and shaped the field after his death in 1858. Psychophysics developed until the birth of psychology as a separate discipline in 1879 with the establishment of Wilhelm Wundt's first laboratory of psychology at the University of Leipzig.
A. Foci of Research
Today, psychology has progressed far further than might have been foreseen by those early physiologists and epistemologists. Modern psychology is broad enough that several different general areas of research can be found within it. The focus of research within these areas emphasizes particular aspects of the governing and control of behavior and psychological traits. These foci of research include developmental, social, experimental, physiological, cognitive, personality, and psychometrics. Their borders often overlap to some degree.
Developmental psychology is primarily concerned with the changes that occur during childhood and adolescence. Topics studied range from the control of movements, the acquisition of language, math and musical abilities, the formation of the self and the identity, the formation of emotional attachments, moral judgments and the development of problem solving and reasoning skills. More recently, the time span examined and compared within developmental psychology has expanded across the lifespan and now includes in some cases the changes associated with aging, even into the elderly years. Social psychology focuses on interpersonal behavior, how people (alone or in groups) think, act, feel, believe or behave based on social situations. This includes situations where they are actually being observed and interacting with others as well as when they are isolated and the observation and interaction with others is imagined or implied. Experimental psychology traditionally encompasses a wide variety of both human and animal research concerned with the general processes of sensation, perception, learning and memory. It does not necessarily concern itself with any underlying biological, chemical or neural mechanisms which support those processes and may not address those mechanisms. Physiological psychology, however, is concerned with the underlying biologically and chemically based mechanisms underlying psychological phenomena. The emphasis on function of the nervous system and hormones is so great that the term behavioral neuroscience has largely replaced the term physiological psychology. However, there is a difference between a strict neuroscientist and a behavioral neuroscientist/physiological psychologist. A neuroscientist's primary interest in the biological or chemical mechanisms of brain function at a cellular or molecular level with often little direct interest in how these cellular or molecular functions influence larger scale phenomena such as memory or emotion or behavior. A behavioral neuroscientist/physiological psychologist's primary interest is in such things as memory or emotion or behavior and they may use cellular or molecular techniques as tools to specifically study those larger scale phenomena. Cognitive psychology studies more complex psychological phenomena such as reasoning, problem solving and creativity. There is much more of an emphasis on how any sensory input is processed, transformed, or elaborated upon rather than the more basic processes involved in basic sensation and perception. Personality psychology examines the consistency in individual's (not groups, like social psychology) beliefs, attitudes and behaviors across a variety of times, places, situations and conditions. Psychometrics is perhaps the least visible and glamorous focus of research but without it most psychology research in other areas would be greatly hampered. Psychometrics studies and develops the theory, techniques and tools of psychological measurements. Without psychometrics, almost every other field within psychology would struggle to do their research without reliable and valid tests, questionnaires, surveys and diagnostic measures to assess the psychological phenomena which they examine.
B. Some Dominant Research
While we have mentioned several major foci of research in psychology, within those foci there are also different perspectives which also guide research. We can look at the perspectives as the particular points of view or positions that psychologists within a larger research focus subscribe to. The focus can be seen as, say, a career like being a doctor or a lawyer or an accountant and the perspective can be seen as a political affiliation like Democrat or Republican or Libertarian. They are not mutually exclusive. But just like political affiliation might influence how one functions within their career, research perspective influences how a psychologist thinks about their research focus.
The Phenomenological perspective, also referred to as Humanistic, was primarily based on the work of Carl Rogers and Abraham Maslow. It stands in contrast to the earlier Psychoanalytic perspective founded by Sigmund Freud. Both emphasized the importance of early childhood in the formation of the personality and later psychological well-being. However, phenomenology holds that people have inborn basic real needs for unconditional positive regard (essentially, unconditional love and acceptance) and self-actualization (reaching one's full potential, "being all you can be"). People, therefore, are basically good. And the conscious mind is in control and aware of behavior and deals with any inner conflicts. Psychoanalysis contends that people unconsciously function primarily on the pleasure principle, simply avoiding pain and approaching pleasure, and because of this people aren't by nature good. Inner conflicts take place in the unconscious mind and people are therefore unaware of the true source of emotional or psychological problems. Hence, the unconscious mind controls behavior and inner conflicts.
The Cognitive perspective, (not the same thing as the cognitive research focus) studies how people perceive, remember, reason, decide, think and the attitudes they hold to find the causes of behaviors and even psychological disorders. For instance, if a person were to be depressed, a therapist with a cognitive perspective might try to determine if the patient held any ideas or views which might be triggering the depression, such as an unreasonably high expectation of perfection on their job or in a personal relationship. Demanding nothing short of perfection from one's self would set the individual up for certain failure and feelings of failure may then lead to depression. By convincing the individual that perfection is not a reasonable attainable standard and replacing that notion with a more realistic one, the root source of the depression would be corrected.
The Evolutionary perspective views human mental and psychological traits as the result of natural selection during the course of human evolution. Such mental and behavioral traits that enhanced reproductive success and survival would have been selected for in the distant past and passed on to offspring. Therefore, the evolutionary perspective argues that modern humans carry these traits, even if they may not confer any advantages today.
The Behavioral perspective holds that behaviors themselves and their repetition are the foundations of learning, adaptation and psychological states. For instance, if someone was shy and had difficulty making friends a therapist from a behavioral perspective would emphasize having the person perform the behaviors that a friendly and outgoing person would do, even if the shy person felt uncomfortable. Initially, the person might be encouraged to practice the behaviors in a safe environment with family members or the therapist or in a group with other shy patients. As the behaviors become easier the patient might then be encouraged to continue to practice and perform those behaviors in other environments and situations, such as at work or while shopping, until the behaviors become so habitual and effortless that they become part of the individual normal way of life. From this perspective, "doing" leads to "being."
In the Biological perspective, the physiological activity of the brain and genetics are the source of psychological traits and phenomena such as anxiety, intelligence, aggression, mental illnesses, etc. This perspective is strongly supported but it is important to illustrate that it does have limitations. For example, identical twins have the same DNA and shared their mother's womb. If one identical twin has schizophrenia, a disorder that we know is inherited genetically and runs in families, the chance of the second identical twin exhibiting the disorder is 50%. If biological and genetic factors were the only ones responsible, then 100% of the second identical twins should exhibit schizophrenia, but that is not the case. However, the random incidence of schizophrenia in the general population is less than 1% and 50% is a tremendous increase over random chance, so biology and genetics is clearly very powerful. And that is what you should remember. Biology is the single most important influence on behavior and psychological traits. However, it is not the only influence and under some conditions its influence can be overruled.
The relationship between focus and perspective can be illustrated with an example: Six developmental psychologists with different research perspectives can be in a room examining the interaction between a father and a young child. The psychologist with a phenomenological perspective may be investigating evidence for the child's need for unconditional positive regard. The one with a psychoanalytic perspective might notice the child's behaviors which seem to act on the principle of seeking pleasurable stimuli and avoiding of unpleasant or punishing stimuli. From a cognitive perspective another might interpret the child's behavior as showing that the child's intellectual understanding of the world around him. An evolutionary perspective would suggest that the behaviors observed in parent and child had helped our ancestors successfully raise their offspring and adapt to their environment. A developmental psychologist with a behavioral perspective would make note of the successful performance of age and situation appropriate behaviors by the child and parent. A biologically oriented researcher might see evidence for the maturing and developing brain in the behaviors and actions of the child. One research focus, child development, but the events seen through six different perspectives.
C. A Rough Historical Timeline
The first significant signpost in psychology occurs before it formally began during the days of the psychophysicists, when Gustav Fechner published the book, Elements of Psychophysics, in 1860. It was this book that described the methods and techniques which the first psychologists used for their first experiments which were rooted in psychophysics. Those first psychologists conducted their research in physiology and philosophy departments until 1879 when Wilhelm Wundt founded the first psychology laboratory at the University of Leipzig in Germany. Wundt found a school of thought referred to as Structuralism which sought to break down the mind's conscious experience into its most basic elemental structural components in order to understand how the mind assembled those parts into our mental experience. It relied on psychophysical approaches and the subjective introspective responses of experimental subjects. This school of thought was eventually challenged by Functionalism which proposed the study of what the mind does rather than conscious experience and its structure. While these two schools of psychology were competing over the value of studying consciousness, in 1900 Sigmund Freud published The Interpretation of Dreams which argued for the value of the study of role the unconscious mind, particularly in the treatment of mental disorders. Very shortly thereafter, in 1905, Alfred Binet and Theodore Simon founded the field of psychometrics by creating the first intelligence test. They were commissioned by the French Ministry of Education upon the occasion of the national legal requirement for all French children to attend school. Theirs was the first objective test to measure a psychological trait.
At this point there is a metaphorical fork in the road in the development of psychology. In 1912 Max Wertheimer founded the Gestalt school in part to oppose structuralism and its emphasis on studying consciousness and the mind by trying to break it down to simple processes. He argued that the mind often didn't build our sensory experiences from simple components so it made no sense to try to break our complex sensory experiences into smaller simpler components. That our mind imposes structure often where there may be none; that we automatically see complex sensory events as whole rather than as a collection of simple elements that we make an effort to connect together. However, at roughly the same time, in the United States, John Watson published Behaviorism in 1913 also to oppose structuralism. But Watson was strongly influenced by functionalism. Rather than dispute how the conscious mind should be studied he argued that consciousness was too problematic and objective observations of overt behavior we the only fit subject for psychological study. Behaviorism eventually became the dominant psychological theoretical perspective and continued to be so for 60 years and emphasized that stimuli and responses could be linked through rewards in complex chains through what may be termed habit. While it was dominant, there were some challengers, notably E.C. Tolman. In 1932, Tolman published Purposive Behavior in Animals and Men which cited instances of learning which could not be explained by simple rewarded stimulus-response habits, but suggested that even rats formed mental maps of their environment when in search of food. However, by 1938 the work of B.F. Skinner reinvigorated behaviorism when he published as The Behavior of Organisms, as well as his work in developing automated animal testing chambers, called Skinner boxes by many. While behaviorism would remain dominant until the 1970's, by 1951, Carl Rogers, one of the founders of phenomenological psychology, published Client-Centered Therapy, which argued that the patient has a conscious capacity to be in control of their behavior. Not long after that, Noam Chomsky published Syntactic Structures in 1957 which suggested that language and grammar is an innate capacity of the human brain rather than a behavior learned by simple behavioral habit. These non-behavioristic points of view began the shift away from behaviorism and towards more cognitively based models of psychology.
III. Some Philosophical Views
Which Shaped Science
As previously mentioned, after the Dark Ages concluded there was a rediscovery of ancient Greek philosophical works which shaped thinking and influenced the development of science and philosophy during the Renaissance. Eventually, these schools of thought also influenced the development of early psychology as well:
Determinism is the view that every event is determined by a sequence prior events, each one causing the one that follows. Therefore, it is possible, by observing events and chains of cause and effect today, to infer or reason what must have occurred in the past to bring about any event or situation we see now. Also, if our understanding of cause and effect is correct we can predict what will happen in the future by carefully observing events and conditions today.
Positivism holds that knowledge should be based on the objective observation of the properties of the world around us either by sensory experience or instruments. Subjective judgments are invalid and unreliable. Theoretical or speculative interpretations of events must be verified by objective observations or be discarded.
Materialism states that everything can be explained or is caused by the physical materials of the universe and laws of nature. In the end, physical matter is the only basis of all reality.
Reductionism asserts that all complex things or problems can be understood by breaking them down simpler or more fundamental components. Solving those smaller simpler problems and then unifying the individual solutions will solve the complex problems. In essence, the whole is just the sum of the parts.
Empiricism holds that the only valid knowledge of the world can be gained through observation and sensory experience and discounts any valid role of intuition or mystical revelation. Observation is also held to be superior to using reason or logic alone to understand the world.
IV. Some Major Figures and Movements in Psychology
A. Philosophical Roots
Born in 1596, Rene Descartes was a French mathematician anatomist and philosopher. Descartes believed in duality, that the mind and body were two separate and distinct entities. Based on his anatomical dissections he agreed with the views of Galen that the body operates essentially like a hydraulic machine, with fluid moving from chambers in the brain and spinal cord, down nerves and into muscles and organs. However, he had noticed that there was one structure in the brain that was unusual. All structures seemed to have a right and left twin on each side of the brain except for one structure called the pineal gland. It was located along the centerline of the brain and directly above the large fluid filled chambers of the brain called ventricles. Descartes proposed that the soul interacted with the body through the pineal gland, controlling the flow of fluid and hence the movement of the body. Descartes was also a nativist, believing that some ideas or information are present at birth and proposed his doctrine of ideas. Under this doctrine, all knowledge can be seen as either innate (present or planted at birth) or derived (acquired through sensory experience). Some of the ideas Descartes held to be innate include God, perfection, geometric axioms and infinity.
Born in 1632, John Locke was a prominent British physician and philosopher. He was an empiricist, and in contrast to Descartes view believed that all human knowledge was acquired through sensory experience. He borrowed a term from the Greek philosopher, Aristotle, and suggested that we are born a tabula rasa, a blank slate, which is written on by our experience. That experience could come from our senses directly or from our mental activity alone, our thoughts or reflections.
B. Physiology & Psychophysics
1. Von Helmholtz
Hermann von Helmholtz (born in 1821) was mentored by Johannes Muller in psychophysics and went on to make numerous contributions in the fields of sensation and perception, including the perception of colors and auditory tones. He was the first to accurately measure the speed of a nerve impulse. By demonstrating that the conduction of a nerve impulse was measurable and not instantaneous, it became clear to psychologists that thought and movement were not simultaneous. However, despite his contributions to psychological research he was uninterested in psychology itself, only in psychophysical measurements. He was a physiologist at heart.
Gustav Fechner (born in 1801) had an active academic career of over 70 years. He began as a physicist and physiologist but as a psychophysicist he made his most enduring contributions. In 1860 he published The Elements of Psychophysics which laid out the methods used by the later structuralist psychologists. However, like Helmholtz, he is not considered a psychologist though he originated many of the techniques. The reason for this distinction is that he also was more interested in making measurements and not interested in promoting or organizing the endeavors of others into what would become a new science.
C. Psychology: Structuralism
Wilhelm Wundt began writing on psychology and psychophysics as early as 1858, even though he did not found his laboratory until 1879. Unlike Fechner he was very concerned with the actual founding of an independent science of psychology. Wundt believed that beyond psychophysical measurements, the conscious experience was a fit topic for study and believed that the mind built up our conscious experience from simple elemental experiences he called immediate experiences (such as the experience of "red") which were assembled together to from mediate experiences (such as the experience of a rose). His view was to eventually determine the structure of the conscious mind (hence, the eventual coining of the term structuralism by his student E.B. Titchener, see below) by analyzing the introspective self-reports of subjects and their immediate experiences in the laboratory. His hope was to create a mental equivalent if chemistry's periodic table of the elements where by the nature and properties of psychological processes could be understood and their interactions predicted.
Carl Stumpf was Wundt's chief competitor. Stumpf's expertise was in the auditory perception of tones and because of the esteem with which he was held by the prominent psychophysicist von Helmholtz, who also worked on auditory tones, Stumpf won a prestigious professorship at the University of Berlin. One of Stumpf's graduate students, Oskar Pfungst, was credited with solving the apparent mystery of Clever Hans, a horse that appeared to respond appropriately to questions, among other things, about mathematics, by tapping his foot. Pfungst demonstrated that the horse was actually responding to subtle unconscious cues that his owner was unintentionally broadcasting to begin tapping and stop tapping. Pfungst's report also influenced John Watson's development of his ideas on behaviorism.
E.B. Titchener founded the department of psychology at Cornell University in 1893, bringing a very modified version of Wundt's psychology which he now formally labeled structuralism. However, had abandoned Wundt's emphasis on immediate experience and had shifted the focus to mediate experience. He also departed radically from his mentor in the techniques used in introspection by his subjects. His departures from Wundt's vision ultimately led to criticisms which accelerated the development and acceptance of behaviorism.
D. Psychology: Functionalism
William James was an American psychologist, with a background in anatomy, physiology and philosophy. Though he founded no formal system he is regarded as the father of functionalism, which held that it was the function of the mind and mental processes that should be studied rather that the structure of the mind. In 1890 James published his influential textbook, The Principles of Psychology, which is still considered a major contribution to the field, especially for its time. James was influenced by the work of Darwin. He agreed with Darwin that the mind may be seen as an adaptation which improved the fitness of a creature to its environment. Therefore, it was the function of the mind that allowed some animals to adapt more successfully. James and functionalism became influences in turn on John Watson and his development of behaviorism.
E. Psychology: Psychoanalysis
Sigmund Freud was a clinical neurologist by training and eventually came to treat nervous and emotional disorders such as hysteria. Due to his medical and scientific background and his interests, we was strongly influenced by the work of Darwin, the psychophysical work of Fechner and the use of hypnosis by individuals such as Franz Mesmer and Jean Martin Charcot who treated mental illness with hypnosis and described it in medical terms. It was the convergence of these influences which led to his development of psychoanalysis. Freud was the first to propose that unconscious processes can affect conscious actions and behaviors. He based his theory of psychiatric disorders on unconscious conflicts between self-gratification and morals But his views were grudgingly accepted by psychologists because they did not offer sufficient explanatory or predictive insight into the structure or nature of the mind. But Freud's medical training made treatment and understanding of mental disorders his primary interest, not basic research on the structure or function of the mind.
F. Psychology: Gestalt
Max Wertheimer was the father of Gestalt psychology, which arose in opposition to the psychology of Wundt and Titchener. Wertheimer was inspired by the sensory illusion of one moving dot of light which was in fact a series of lights turned on and off in a sequence. This appearance of motion where nothing had actually moved led Wertheimer to propose that the mid did not process sensory input and build our conscious experience bit by bit in the way that structuralists believed. Gestaltists believed that some complex perceptions cannot be reduced to simpler sensory experiences and that the mind operated on general organizing principles to perceive some complex sensory stimuli based on properties like proximity, similarity and closure. Basically gestalt says that the sensory whole is not the mere sum of its parts.
G. Behaviorism, Purposive Behaviorism & Neobehaviorism
John Watson was trained as an animal behaviorist and through his dissatisfaction with structuralism and the influence of functionalism and the analysis of behavior (remember Oskar Pfungst's investigation of Clever Hans?) Watson proposed that psychology should rely only on the study of objectively observable behavior, and not the mind, both the conscious and unconscious. He termed this school of thought behaviorism, in which behavior is described in terms of physiological responses to stimuli. His book, Behaviorism, published in 1913 ushered in that point of view which became the dominant school of thought in psychology for 60 years and led to the proposition that learning consisted of learned responses made to stimuli which signaled reward,
E.C. Tolman, while technically a behaviorist, did not believe that the mind should be completely abandoned as a subject for study. In Purposive Behavior in Animals and Men, Tolman illustrated examples of learning which could not be explained by simple Watsonian behavioral principles, but seemed to imply that even rats form expectations and even mental representations, "cognitive maps", of their spatial surroundings. His work laid an early basis for cognitive views of psychology, especially in animal learning, which were to follow much later.
A contemporary of Tolman's, B.F. Skinner revitalized behaviorism with his investigations into what he termed operant conditioning. While similar in some respects to the habit-like learning of other behaviorists, in operant conditioning the animal's own responses have consequences which are then either reinforced or not reinforced rather than by stimuli that signaled reward or punishing consequences. Skinner also developed automated chambers for animal testing which not only saved labor but also time and allowed for greater ease of experimentation as well as control and consistency over stimuli and procedures.
V. The Swinging Pendulum of Influence
We have seen that psychology has roots in both biology and philosophy and that ever since the beginning of psychology there has been a bit of a tug-of-war for dominance in how psychology approaches the study of the mind. From the physiologists to the philosophers, the functionalists to the structuralists, the behaviorists to the cognitivists, opposing views have competed to explain the phenomena of our mental lives. Today, much of the general scientific debate about the relative importance of nature and nurture has spilled over into psychology. What has the final say in determining who we are or what we wind up becoming: biology and genetics or experience and environment? The short and enlightened answer is that there isn't a "winner-take-all" competition between the biological and non-biological influences that make up who we are. The evidence suggests that biological influences are the single biggest influence on psychological processes, but they are clearly not the only influence. Remember the example of identical twins with schizophrenia. Though they have identical DNA and shared the same womb, if one twin develops the disorder the chances of the second twin developing it are only 50%. Clearly, if the influence of biology was "winner-take-all" that would be impossible. However, sorting through all the other potential factors within the vast possibilities included under experience and environment, and potential interactions among those influences, can be so complicated that often simple biological explanations may be given more weight than they might otherwise deserve. The good news is that there is then plenty of work for psychologists to do to fully understand how experience and environment can modify the role of the biological factors on our mental life and our psychological make-up. Just as the pendulum of influence has swung back and forth among competing points of view through out the history of psychology, it is likely to continue swinging far into the foreseeable future.