Schools of Psychology (Modern Psychology)
Structuralism (Mental Chemistry)
Wilhelm Wundt (along with one of his English students, Edward Titchener, who helped establish psychology in the USA) developed the first systematic position, or school of thought, in psychology – structuralism (structuralism a theory derived from the use of psychophysical methods, so called because it focuses on the structure of the mind) . According to Wundt, psychology is the science of immediate experience, unbiased by any interpretation. Wundt put students through an arduous training in the method of introspection (looking inward) [introspection literally, looking inward, this is an observational method used to describe the elements of experience (colours, tones, tastes and so on)]to single out those who could describe the elements of experience – colours, tones, tastes and so on. In our example, a good introspectionist would describe only the intensity and clarity of the sensations that occur in viewing the image, such as its blueness. Like chemistry, psychology consists of analysis – discovering the basic elements of conscious thought – and synthesis – discovering connections between elements and the laws governing these connections. To qualify as an element, an experience has to be irreducibly simple. Titchener even dared to number the elements of consciousness and offered what one might view as a ‘periodic table’ of the mind. Elementary sensations had to be combined because, as Wundt recognized, we experience conscious thought as a unity, not as a series of varied sensations of brightness, hue, shape etc. Wundt’s doctrine of apperception describes a process of ‘creative synthesis’ by which elementary experiences are organized into a whole. And his law of psychic resultants posits that psychic compounds have new properties that are ‘by no means the mere sum of the characteristics of the elements’.
Wundt was profoundly influential, not to mention prolific – if you read his works at the rate of 60 pages a day, it would take two and a half years to finish them. But the method of introspection did not stand the test of time and by the early twentieth century had even been labelled ‘superstitious’ by an American behaviourist, John Watson. In fact, vehement reaction against the limitations of structuralism defined much of what subsequently happened in psychology for many years.
Functionalism (Mental accomplishment)
Preoccupation with the structure of the mind was replaced by a second major system of thought in psychology, which focused on function. Functionalism(functionalism addresses the very practical question of what functions the
mind, or mental processes, accomplish) addressed the very practical question of what the mind, or mental processes, accomplish. The precept ‘thinking is for doing’ is the hallmark of functionalism. Although it arose in the USA and was the first uniquely American system of psychology, it owed much to the Englishman Charles Darwin. The notion of function is central to Darwin’s theory of evolution, as the physical characteristics of a species evolve to meet its requirements for survival. The idea that behaviour might also reflect adaptation to the environment soon followed. Darwin’s seminal work, On the Origin of Species by Means of Natural Selection (1859), also raised the possibility of continuity in behaviour and mental functioning between animals and humans, prompting the laboratory study of mental functioning in animals. Finally, Darwin’s observation of variation among members of the same species focused attention on individual differences in psychology.
The most important exponent of functionalism was William James (1842–1910), who argued that: ‘No one ever had a simple sensation by itself ’, he proposed, the most important thing about consciousness is its continual flow, and he coined the famous phrase ‘stream of consciousness’ to emphasize this fact. He was interested in the process of conscious activity (e.g. perceiving and learning) and viewed the attempt to divide consciousness into distinct elements as misguided. From James’ perspective, the function of consciousness is to guide behaviour that will help the organism adapt to the environment. He felt that consciousness must have some biological use or else it would not have survived. Not surprisingly, James saw psychology as a biological science.
Unlike Wundt, James never set out to found anything (he started a laboratory at Harvard University in 1875 but did not carry out any laboratory research). Yet his impact on psychology was equally profound. In Principles of Psychology, published in 1890, James offered a vision that is closer to modern psychology than anyone else at that time. Indeed, the two volumes, with chapters on such topics as reasoning, habit, emotion, instinct, will, the self, attention and hypnotism, remain useful reading for psychologists today. With the publication of this work, James felt that he had said all he knew about psychology and devoted the rest of his life to philosophy. But it was enough to pave the way for comparative psychology and the study of individual differences to become part of the mainstream of psychology. After James, functionalism was developed more formally as a ‘school’ by John Dewey (1859–1952) and James Angell (1869–1949). Functionalism shifted attention away from the exclusive focus on private experience (consciousness) to include the study of objective, observable behaviour. Unlike structuralism, functionalism was not supplanted but provided a bridge for the emergence of the polar opposite of structuralism – a psychology that focused on behaviour and eschewed study of the mind.
[William James (1842–1910) was the most important exponent of functionalism. James argued that the most important thing about consciousness is its continual flow, coining the famous phrase ‘stream of consciousness’. Unlike Wundt, he viewed the attempt to divide consciousness into distinct elements as misguided. From James’ perspective, the function of consciousness is to guide behaviour that will help the organism adapt to the environment. In Principles of Psychology (1890) James offered a vision that is closer to modern psychology than that of anyone else at that time. With the publication of this work, James felt that he had said all he knew about psychology and devoted the rest of his life to philosophy. But it was enough to pave the way for comparative psychology and the study of individual differences to become part of the mainstream of psychology.]
Behaviourism (Objective Psychology)
The emergence of functionalism had been evolutionary rather than revolutionary, with structuralism maintaining a strong but not exclusive hold on psychology as it entered the second decade of the twentieth century. But a student of Angell’s, John Watson, changed this with the publication of a broad, cutting attack on existing systems in psychology. ‘Psychology as the behaviorist views it’ (1913) served as the manifesto for a revolution in psychology:
Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior . . . The behaviorist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of the behaviorist’s scheme of investigation. Like Wundt, Watson set out to promote something new – a totally objective psychology, whose subject matter was observable behaviour. Stimulus–response units were seen to be the basic building blocks of complex behaviour. So, even in rejecting structuralism, Watson shared with it an analytic and atomistic point of view. Because Watson was more interested in working with animals than humans, it is not surprising that he viewed behaviourism (behaviourism a totally objective psychology, whose subject matter is observable behaviour) as ‘a direct outgrowth of studies in animal behavior’. By the turn of the century the study of animal behaviour had become widespread, and experimental animal psychology was growing rapidly. Edward Thorndike (1874–1949) – one of the most important figures in the development of animal psychology – is credited with introducing the experimental investigation of animal behaviour. To study ‘animal intelligence’, he put cats in a cage, placed food outside the cage door and timed how long it took the cat to learn how to escape. In the process of trial-and-error learning, Thorndike observed that responses were ‘stamped in’ or ‘stamped out’, depending on their consequences. He formalized this observation in his famous law of effect: [law of effect articulates two central experimental findings: 1) any act that produces satisfaction is more likely to recur; and 2) any act that produces discomfort is less likely to recur ] ‘Any act which in a given situation produces satisfaction becomes associated with that situation, so that when the situation recurs the act is more likely to recur also. Conversely, any act which in a given situation produces discomfort becomes dissociated from that situation, so that when the situation recurs the act is less likely than before to recur’. In building on Thorndike’s work, atson purged it of mentalistic ideas like ‘satisfaction’. Watson also profited from the work of the Russian physiologist, Ivan Pavlov (1849–1936). In his Nobel Prize-winning work on digestion, Pavlov discovered that hungry dogs would salivate at the sight of the person who brought them their food. At first, he considered this ‘psychic secretion’ a nuisance, but soon he realized that it revealed a very basic form of learning. He went on to show that dogs could be trained, or conditioned, to salivate at the onset of an arbitrary stimulus (e.g. the sound of a bell) if it was immediately followed by food. Without intending to do so, Pavlov had provided psychology with a basic element, the stimulus–response association – also used by Watson as the foundation of behaviourism. Watson had argued that, with the appropriate stimuli, an organism can learn to behave (respond) in specific ways, much like Pavlov’s dogs. Along with his student, Rosalie Rayner, he showed – through an experiment that raised obvious ethical concerns – how fear could be learned. Little Albert, an 11-monthold child, was shown a white rat that he was not afraid of. Each time he was shown the rat, the experimenter made a loud noise, eliciting a startle reaction (Watson & Rayner, 1920). After just seven trials, the rat alone, without the accompanying noise, produced fear (crying). In the same year, Watson’s formal career as a psychologist ended prematurely and abruptly in the midst of highly publicized divorce proceedings, but his legacy lived on. Behaviourism thrived well into the 1960s, especially in the USA, where it evolved under the direction of arguably the most influential psychologist of the twentieth century, Burrhus Fredrick Skinner (1904–90) and became known as radical behaviourism.
First, it is ‘radical’ because Skinner completely accepted private life as behaviour. Second, a mental state is treated as a sub-category of the environment – so each of us is affected by both the external environment and our own internal environment. Third, the same principles apply equally well to both environments. Fourth, radical behaviourists focus only on behaviour and the variables that control it. They look in only two places for these variables: the conditions that immediately precede the behaviour and the conditions that immediately follow it. Imagine you are playing table tennis. As you hit the ball, you say to yourself, ‘Stay focused.’ You notice that the ball lands on the table more frequently when you do this. So this outcome (ball on the table) keeps you saying that phrase to yourself as you hit the ball. Consider what would happen if you said the phrase but the ball hit the net as often as it landed in play. Eventually you would stop saying the phrase to yourself.
There are two points to notice here:
1. It is the functional relationship between the outcome and the phrase that determines the likelihood that you will repeat the phrase.
2. The phrase itself has no power over the behaviour (it does not directly ‘cause’ the behaviour).
Radical behaviourism is sometimes viewed as simplistic, but Skinner’s approach was far from simple. In Science and Human Behavior he notes that behaviour is very complex and difficult to study: ‘Since it is a process, rather than a thing, it cannot be easily held for observation. It is changing, fluid, and evanescent, and for this reason it makes great technical demands upon the ingenuity and energy of the scientist’. Skinner focused on establishing laws of behaviour (empirical relationships between environmental events and behaviour) based on intensive observation of a single subject under carefully controlled experimental conditions. His approach, the experimental analysis of behaviour, investigated ‘operant’ behaviours – so-called because they ‘operate’ on the subject’s environment. Skinner viewed this approach as more representative of real-life learning. Operant behaviours are distinguished from the kind studied by Pavlov –‘respondent’ behaviours, which are a response to a known stimulus. Skinner’s classic work involved the study of bar pressing (or pecking) by rats (or pigeons) in a ‘Skinner box’ that was constructed to eliminate all extraneous stimuli. A hungry animal was placed in the box and allowed to explore it. Sooner or later the animal would accidentally press a lever that released a food pellet. The food acted as a reinforcing stimulus (or reinforcer) for the bar-pressing behaviour, increasing the probability of its future occurrence. In other words, the animal ‘worked’ (pressed the bar) because there was a ‘payoff’ (food). This is an example of operant conditioning. The manner in which the payoff occurred – the schedule of reinforcement – influenced bar pressing. Schedules of reinforcement could vary according to time interval schedules (in human terms, this might be the weekly pay check), or work ratio schedules (a pay cheque based, for example, on number of items sold). Ratio schedules produce greater rates of behaviour, or faster learning. Schedules can also vary in terms of whether they are fixed or variable. Interestingly, a variable ratio schedule, in which the rate of reinforcement of the rat varies somewhat according to the number of bar presses it makes, produces the highest rate of responding. Skinner went on to show that operant conditioning can take several forms. One of its first applications to human behaviour occurred in 1948 when it was used to treat an institutionalized, profoundly retarded person (Fuller, 1949). Systematic research to make the experimental analysis of behaviour useful in addressing human problems soon followed, giving rise to the widespread use of teaching machines (‘programmed learning’), behaviour modification in educational settings, and treatments for emotional and behavioural disorders.
The application of operant procedures to address socially important behaviours became known as applied behaviour analysis in the 1960s. Like Watson, who envisioned behavourism giving rise to ‘saner living’, Skinner saw his laboratory research as also providing a technology of behaviour that could improve society. In his novel Walden Two (1948), Skinner outlines in detail the mechanics of a society based on behavioural principles. Most modern behaviourists no longer adhere strictly to the behaviourism espoused by Watson or Skinner. But even psychologists who reject behaviourism in all its forms are indebted to it. The objective approach to understanding behaviour has its roots in structuralism and evolved though functionalism to reach its zenith in behaviourism. This is the hallmark of modern psychology.
Gestalt Psychology: (Connections)
While functionalism followed structuralism in the USA, and behaviourism arose in opposition to both, a different kind of opposition to structuralism emerged in Germany – Gestalt psychology. The Gestalt attack on structuralism in Europe was independent of the opposition that had developed in the USA. It arose out of a simple observation by its founder, Max Wertheimer (1880–1943), whose paper ‘Experimental studies of the perception of movement’ marks the beginning of Gestalt psychology. Wertheimer notes that we can see motion or movement even when no actual movement takes place. For example, when two lights flash in quick succession, we see what appears to be movement from one to the other and back again. Wertheimer called this the ‘phi phenomenon’.
It was impossible to explain the phi phenomenon in structuralist terms by describing each elementary sensation (any more than we can explain a melody by describing each individual note). So how did Wertheimer explain it? He did not. He saw no need for explanation, for, he argued, apparent movement could not be reduced to anything simpler. From the Gestalt perspective, the perception forms a whole (in German, Gestalt means ‘form’ or ‘entire figure’), or unity (the movement), that is greater than the sum of its parts (the two lights). Gestalt psychology therefore challenged the associationist views that prevailed at the time. Gestalt psychology is based on the principles that complex mental experience exists on its own, and that perception is composed not of elements but of structured forms. Perhaps the best known Gestalt psychologist, Wolfgang Kohler (1887–1967), reminds us that ‘the concept “Gestalt” may be applied far beyond the limits of sensory experience’. Kohler studied apes and observed that they solved problems (e.g. by joining two short sticks to retrieve a banana) by ‘insight’, or by spontaneously seeing relationships (in this case, between two sticks). This contrasted with the work of behaviourists, whom he criticized for structuring animal problem-solving tasks in such a way that they allowed only trial and error behaviour. For example, an animal in a maze cannot see the overall design of the maze, only the alley it is in, and it is therefore limited to using trial and error. Although it did not survive as a distinct school of psychology much beyond the 1950s, Gestalt principles were incorporated into other areas of psychology, particularly thinking and learning. It even influenced early social psychology.
Other School of Thoughts:
Many important developments in the emergence of psychology took place outside the context of the ‘schools’. he first began within a few years of the establishment of Wundt’s laboratory at Leipzeig.
Memory – [Hermann Ebbinghaus]
Shortly after Wundt stated that it was not possible to investigate higher mental processes experimentally, a compatriot, Hermann Ebbinghaus (1850–1909), devised ingenious experimental methods for studying memory (the process of learning and forgetting) using only himself as the subject. One experimental technique involved learning nonsense syllables – syllables that have no meaning and therefore no connections to anything in a subject’s experience. Ebbinghaus formed the syllables by using all possible combinations of consonants the test of time as his findings were later replicated by others and many remain valid today. According to Roediger (1999), Ebbinghaus solved three important problems faced by psychologists in their work:
1. converting unobservable mental processes into observable behaviour; 2. measuring the behaviour reliably; and 3. showing how relevant variables affect the behaviour. In doing so, he started a whole new field of study that remains vital today and set the stage for later study of many aspects of cognition.
Individual differences [ Francis Galton]
In addition to his remarkable work on memory, Ebbinghaus was the first to publish on intelligence testing in children. He developed a test, still included in test batteries today, which anticipated psychometrics, (psychometrics the theory and measurement of psychological variables such as IQ (intelligence quotient)) the theory and measurement of psychological variables. It was not until 1905, however, that Alfred Binet (1857–1911), along with fellow French researcher Théodore Simon, produced the first successful test of general intelligence. These efforts all rested on the earlier work of the Englishman Sir Francis Galton (1822–1910), who initiated the whole idea of ‘mental tests’. He assumed that intelligence could be measured in terms of sensory abilities, reasoning that the more the senses perceive differences – for example, the ease with which weights can be discriminated – the larger the field upon which our judgement and intelligence are able to act (Galton, 1928). Galton was also interested in the inheritance of mental abilities. Inspired by the work of his cousin, Charles Darwin, he did much to introduce the spirit of evolution to psychology.
His first influential work was Hereditary Genius (1869), which applies statistical ideas to the problem of heredity and documents the genealogy of 997 eminent men. Galton calculated that the chance (statistically) of members of this group having an eminent relative was less than 1 per cent. What he found was that 33 per cent had eminent relatives. His conclusion that genius is inherited would not be justified by today’s research standards. These would require his findings to be compared to those for a group of non-eminent men, and would require closer examination of an alternative hypothesis – namely, that relatives might share similar environments and not just genes. Galton’s interest in documenting human differences led him to develop statistical methods, perhaps the most famous of which is the correlation or ‘co-relation’ (Galton’s term) between two variables. Indeed, Galton’s pioneering work gave rise to a number of statistical tools that psychologists still use today. Two further, and better known, developments took place outside the mainstream of psychology – Sigmund Freud’s psychoanalysis and Jean Piaget’s genetic epistemology. Neither had an immediate impact on the subject, but over the course of time their influence was profound.
[Francis Galton (1822–1910) was instrumental in developingpsychometrics – the theory and measurement of psychologicalvariables. He reasoned that the more the senses perceive differences (for example, the ease with which weights can be discriminated), the larger the field upon which our judgement and intelligence are able to act. Inspired by the work of his cousin, Charles Darwin, Galton introduced the spirit of evolution to psychology. His first influential work, Hereditary Genius (1869), applies statistical ideas to the problem of heredity, documenting the genealogy of 997 eminent men. Galton’s interest in documenting human differences led him to develop statistical methods, perhaps the most famous being ‘co-relation’ – or correlation– between two variables.]
Psychoanalysis [Sigmund Freud]
Sigmund Freud (1856–1939), a Viennese physician, formulated a revolutionary theory of human behaviour. Although familiar with the experimental psychology movement, Freud’s data was not obtained from controlled experiments but by listening to patients who were not suffering from any familiar disease. He applied his own idiosyncratic interpretation of data to formulate theories. By the mid 1890s, he had become convinced that traumatic sexual experiences in childhood were responsible for many of his patients’ symptoms. These painful memories were pushed out of consciousness (‘repressed’) and the task of Freud’s ‘talking cure’ – psychoanalysis – [psychoanalysis Freud’s ‘talking cure’, which aimed to bring pathological memories into conscious awareness and was used by Freud as the foundation for developing a theory of personality] was to bring such memories into conscious awareness. Over the course of his career, Freud used psychoanalysis as the foundation for developing a theory of personality that included a number of mental structures – the id, ego and superego. These structures were fundamentally different from those investigated by Wundt. The id, together with portions of the ego and superego, were considered to be unconscious and therefore could not be analysed by introspection, and, unlike Wundt, Freud was also interested in the function of these structures. There were no points of contact between psychology and psychoanalysis. Each had a different approach, and psychologists were particularly critical of Freud’s methods, including the conditions under which he collected his data, the unstated process by which he moved from data to conclusions, vagueness of terms, and the difficulty of deriving empirically testable hypotheses.
Freud, for his part, simply stated that his work was ‘based on an incalculable number of observations, and only someone who has repeated those observations on himself and on others is in a position to arrive at a judgment of his own upon it’. But because no one knew how Freud reached his judgements, they could not be repeated. Eventually even his own disciples grew frustrated and split from him. Subsequent attempts to describe the dynamics of the mind that build on psychoanalytic thinking are generally referred to as psychodynamic theories. Although psychoanalysis never became a ‘school’ in psychology (its home always was and remains in freestanding psychoanalytic institutes outside academia), many of his concepts came to have a profound influence on psychology, and on twentieth century civilization in general.
Genetic epistemology [Jean Piaget]
How do we come to know something? This is the question addressed by the branch of philosophy concerned with the study of knowledge – epistemology [genetic epistemology the study of the origin of knowledge in child development, as practised by Jean Piaget] . Instead of using only logical arguments to address this question, a Swiss biologist, Jean Piaget (1896–1980), studied developmental changes in knowing and the nature of knowledge. Piaget did not identify himself as a psychologist, instead labelling his work as genetic epistemology, the study of the origin of knowledge in child development. Drawing on his work with fresh water molluscs, his greatest insight was simply that knowledge is a relationship between the knower and the known. The knower always provides a framework for the acquisition of knowledge, which simultaneously influences (assimilates) and is influenced by (accommodates) what is known. As the knower changes, so does what is known. Piaget argued that a child understands an object by acting on it either physically or mentally and thereby constructs knowledge. Infants develop cognitive structures or schemes, which are organized patterns of actions that reflect a particular way of interacting with the environment. Cognitive structures of older children, from about seven years on, reflect abstract mental operations. These operations, or internalized actions that are organized structures, allow older children to realize that quantities remain constant (are conserved) despite changes in appearance. Unlike behaviourists, Piaget ignored the issue of learning, which he long dismissed as ‘the American question’, and his theory of intelligence had little impact outside of Europe until John Flavell (1963) introduced Piaget’s work to the English-speaking world. Faced with the difficulty of Piaget’s writings and the scope of his work – which covered not only intelligence but also perception, language, play and such psychological processes as memory – it was all too easy for psychologists to focus only on aspects of the theory. Piaget considered this fragmentation the most common abuse of his work. And yet, even though much of his work was based on observation of his own children and has been criticized for relying too heavily on children’s verbal abilities to explain their understanding, it had a profound impact on developmental psychology. The most persistent and successful challenge to Piaget’s findings came from work inspired by a new approach to understanding cognitive processes.
Cognitive Revolution
It has been said that psychology ‘lost its mind’ with the advent of Watsonian behaviourism. It could equally be said that several factors led psychology to ‘regain its mind’, including the realization that:
1. the strict methodological controls that were part and parcel of behaviourism had resulted in the elimination of those concepts that related most closely to people’s everyday experience (e.g. their experience of consciousness);
2. the stimulus–response approach was inadequate for explaining many psychological phenomena (e.g. how language develops); and
3. behaviourism had thereby deprived psychology of some of its most interesting problems (e.g. how people ascribe meaning to events and how this meaning influences subsequent behaviour).
The ‘cognitive revolution’, which pushed behaviourism from its dominant position in psychology, cannot be traced to a founding figure or the publication of a particular paper. But many agree that Ulrich Neisser’s book Cognitive Psychology (1967) and Donald Broadbent’s work at the Applied Psychology Research Unit in Cambridge were important influences. Broadbent, in his work on human skills and performance (‘human factors’), noted that humans are guided by information, or ‘feedback’, provided by machines (e.g. instruments in
an aircraft cockpit), and that often the individual will no make use of all the information in operating the achine (flying the aircraft). The problem for the person operating the machine is the allocation of attention to direct the processing of available information. So, continuing our aircraft example, on different occasions it will be more relevant for the pilot to focus attention on the altimeter or the speed indicator, or to distribute her attention more widely across multiple sources of information. For example, both the altimeter and the speed dial may provide critical information during landing. Integrating this work with ideas from information theory – a branch of communications sciences that provides an abstract way of analysing the processing of knowledge – Broadbent id much to develop the human information-processing approach, which came to inform research in virtually all areas of modern psychology. Contemporaneous with Broadbent’s work was the emergence of the computer as a research tool. Computers gripped the imagination of psychologists, soon becoming a metaphor for mental functioning. They showed that complex actions can be broken down into a series of binary, yes-or-no decisions. In principle, this meant that, with a system of feedback, a computer could duplicate the behaviour of a human, no matter how complex that behaviour. These ideas quickly led to new models of behaviour that incorporated such mentalistic concepts as plans and goals. The information-processing approach is often described as an abstract analysis. This means that it does not focus on the operation of the physical components of the processing system – whether they be brain cells or digital switches. Both the brain and the computer consist of millions of components, yet the behaviour of computers can be understood by studying the programs that run them. In the same way, a good account of human behaviour is considered possible by using terms abstract enough to transcend the operation of the brain’s approximately 100 billion nerve cells.
From the human information-processing perspective, information delivered to the senses is translated into a cognitive code. In other words, specific aspects of the environment are detected and their organization begins. These are then delivered to working memory, a kind of workbench for cognitive codes where goals are established and a central processor comes into play. Two types of processing can occur: automatic processing, which is effortless and unconscious, and controlled processing, which is effortful and conscious. More recently, the computer metaphor has been challenged by the ‘brain metaphor’, which gave rise to the connectionist approach – also known as a ‘neural network’ approach, meaning that it is informed by a view of how the nervous system might compute things. Although largely interested in idealized nervous systems, connectionists do take pains to show that the human nervous system could process material in ways that are similar to their idealized systems. These systems conduct processing in parallel, not in the serial manner assumed in the information-processing approach. Connectionists also reject the idea of a central control unit – the notion of ‘boss’ neurons directing other neurons’ activities is foreign to connectionism – and argue that mental processes cannot be broken down into components. Instead, the neural and cognitive systems function as a whole. It is important to note that, while the cognitive revolution did not embrace biological explanations of behaviour, neither did it actively banish biology from psychology – unlike its behavioral predecessor. Startling new advances in the study of the nervous system have been made possible by technology, and neurobiologists (biologists who study the nervous system) can now study the brain in ways that were unimaginable just a couple of decades ago. Imaging techniques allow us to see the brain at work as it engages in various activities. It is also possible to measure brain activity in a very fine-grained manner, focusing on areas that might be as small as a few cubic millimeters. So far, these techniques have been applied to basic psychological processes such as reading, listening, remembering and experiencing emotion, and more recently to the study of social cognition (the processes involved in perceiving, interpreting, and acting on social information,
Structuralism (Mental Chemistry)
Wilhelm Wundt (along with one of his English students, Edward Titchener, who helped establish psychology in the USA) developed the first systematic position, or school of thought, in psychology – structuralism (structuralism a theory derived from the use of psychophysical methods, so called because it focuses on the structure of the mind) . According to Wundt, psychology is the science of immediate experience, unbiased by any interpretation. Wundt put students through an arduous training in the method of introspection (looking inward) [introspection literally, looking inward, this is an observational method used to describe the elements of experience (colours, tones, tastes and so on)]to single out those who could describe the elements of experience – colours, tones, tastes and so on. In our example, a good introspectionist would describe only the intensity and clarity of the sensations that occur in viewing the image, such as its blueness. Like chemistry, psychology consists of analysis – discovering the basic elements of conscious thought – and synthesis – discovering connections between elements and the laws governing these connections. To qualify as an element, an experience has to be irreducibly simple. Titchener even dared to number the elements of consciousness and offered what one might view as a ‘periodic table’ of the mind. Elementary sensations had to be combined because, as Wundt recognized, we experience conscious thought as a unity, not as a series of varied sensations of brightness, hue, shape etc. Wundt’s doctrine of apperception describes a process of ‘creative synthesis’ by which elementary experiences are organized into a whole. And his law of psychic resultants posits that psychic compounds have new properties that are ‘by no means the mere sum of the characteristics of the elements’.
Wundt was profoundly influential, not to mention prolific – if you read his works at the rate of 60 pages a day, it would take two and a half years to finish them. But the method of introspection did not stand the test of time and by the early twentieth century had even been labelled ‘superstitious’ by an American behaviourist, John Watson. In fact, vehement reaction against the limitations of structuralism defined much of what subsequently happened in psychology for many years.
Functionalism (Mental accomplishment)
Preoccupation with the structure of the mind was replaced by a second major system of thought in psychology, which focused on function. Functionalism(functionalism addresses the very practical question of what functions the
mind, or mental processes, accomplish) addressed the very practical question of what the mind, or mental processes, accomplish. The precept ‘thinking is for doing’ is the hallmark of functionalism. Although it arose in the USA and was the first uniquely American system of psychology, it owed much to the Englishman Charles Darwin. The notion of function is central to Darwin’s theory of evolution, as the physical characteristics of a species evolve to meet its requirements for survival. The idea that behaviour might also reflect adaptation to the environment soon followed. Darwin’s seminal work, On the Origin of Species by Means of Natural Selection (1859), also raised the possibility of continuity in behaviour and mental functioning between animals and humans, prompting the laboratory study of mental functioning in animals. Finally, Darwin’s observation of variation among members of the same species focused attention on individual differences in psychology.
The most important exponent of functionalism was William James (1842–1910), who argued that: ‘No one ever had a simple sensation by itself ’, he proposed, the most important thing about consciousness is its continual flow, and he coined the famous phrase ‘stream of consciousness’ to emphasize this fact. He was interested in the process of conscious activity (e.g. perceiving and learning) and viewed the attempt to divide consciousness into distinct elements as misguided. From James’ perspective, the function of consciousness is to guide behaviour that will help the organism adapt to the environment. He felt that consciousness must have some biological use or else it would not have survived. Not surprisingly, James saw psychology as a biological science.
Unlike Wundt, James never set out to found anything (he started a laboratory at Harvard University in 1875 but did not carry out any laboratory research). Yet his impact on psychology was equally profound. In Principles of Psychology, published in 1890, James offered a vision that is closer to modern psychology than anyone else at that time. Indeed, the two volumes, with chapters on such topics as reasoning, habit, emotion, instinct, will, the self, attention and hypnotism, remain useful reading for psychologists today. With the publication of this work, James felt that he had said all he knew about psychology and devoted the rest of his life to philosophy. But it was enough to pave the way for comparative psychology and the study of individual differences to become part of the mainstream of psychology. After James, functionalism was developed more formally as a ‘school’ by John Dewey (1859–1952) and James Angell (1869–1949). Functionalism shifted attention away from the exclusive focus on private experience (consciousness) to include the study of objective, observable behaviour. Unlike structuralism, functionalism was not supplanted but provided a bridge for the emergence of the polar opposite of structuralism – a psychology that focused on behaviour and eschewed study of the mind.
[William James (1842–1910) was the most important exponent of functionalism. James argued that the most important thing about consciousness is its continual flow, coining the famous phrase ‘stream of consciousness’. Unlike Wundt, he viewed the attempt to divide consciousness into distinct elements as misguided. From James’ perspective, the function of consciousness is to guide behaviour that will help the organism adapt to the environment. In Principles of Psychology (1890) James offered a vision that is closer to modern psychology than that of anyone else at that time. With the publication of this work, James felt that he had said all he knew about psychology and devoted the rest of his life to philosophy. But it was enough to pave the way for comparative psychology and the study of individual differences to become part of the mainstream of psychology.]
Behaviourism (Objective Psychology)
The emergence of functionalism had been evolutionary rather than revolutionary, with structuralism maintaining a strong but not exclusive hold on psychology as it entered the second decade of the twentieth century. But a student of Angell’s, John Watson, changed this with the publication of a broad, cutting attack on existing systems in psychology. ‘Psychology as the behaviorist views it’ (1913) served as the manifesto for a revolution in psychology:
Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior . . . The behaviorist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of the behaviorist’s scheme of investigation. Like Wundt, Watson set out to promote something new – a totally objective psychology, whose subject matter was observable behaviour. Stimulus–response units were seen to be the basic building blocks of complex behaviour. So, even in rejecting structuralism, Watson shared with it an analytic and atomistic point of view. Because Watson was more interested in working with animals than humans, it is not surprising that he viewed behaviourism (behaviourism a totally objective psychology, whose subject matter is observable behaviour) as ‘a direct outgrowth of studies in animal behavior’. By the turn of the century the study of animal behaviour had become widespread, and experimental animal psychology was growing rapidly. Edward Thorndike (1874–1949) – one of the most important figures in the development of animal psychology – is credited with introducing the experimental investigation of animal behaviour. To study ‘animal intelligence’, he put cats in a cage, placed food outside the cage door and timed how long it took the cat to learn how to escape. In the process of trial-and-error learning, Thorndike observed that responses were ‘stamped in’ or ‘stamped out’, depending on their consequences. He formalized this observation in his famous law of effect: [law of effect articulates two central experimental findings: 1) any act that produces satisfaction is more likely to recur; and 2) any act that produces discomfort is less likely to recur ] ‘Any act which in a given situation produces satisfaction becomes associated with that situation, so that when the situation recurs the act is more likely to recur also. Conversely, any act which in a given situation produces discomfort becomes dissociated from that situation, so that when the situation recurs the act is less likely than before to recur’. In building on Thorndike’s work, atson purged it of mentalistic ideas like ‘satisfaction’. Watson also profited from the work of the Russian physiologist, Ivan Pavlov (1849–1936). In his Nobel Prize-winning work on digestion, Pavlov discovered that hungry dogs would salivate at the sight of the person who brought them their food. At first, he considered this ‘psychic secretion’ a nuisance, but soon he realized that it revealed a very basic form of learning. He went on to show that dogs could be trained, or conditioned, to salivate at the onset of an arbitrary stimulus (e.g. the sound of a bell) if it was immediately followed by food. Without intending to do so, Pavlov had provided psychology with a basic element, the stimulus–response association – also used by Watson as the foundation of behaviourism. Watson had argued that, with the appropriate stimuli, an organism can learn to behave (respond) in specific ways, much like Pavlov’s dogs. Along with his student, Rosalie Rayner, he showed – through an experiment that raised obvious ethical concerns – how fear could be learned. Little Albert, an 11-monthold child, was shown a white rat that he was not afraid of. Each time he was shown the rat, the experimenter made a loud noise, eliciting a startle reaction (Watson & Rayner, 1920). After just seven trials, the rat alone, without the accompanying noise, produced fear (crying). In the same year, Watson’s formal career as a psychologist ended prematurely and abruptly in the midst of highly publicized divorce proceedings, but his legacy lived on. Behaviourism thrived well into the 1960s, especially in the USA, where it evolved under the direction of arguably the most influential psychologist of the twentieth century, Burrhus Fredrick Skinner (1904–90) and became known as radical behaviourism.
First, it is ‘radical’ because Skinner completely accepted private life as behaviour. Second, a mental state is treated as a sub-category of the environment – so each of us is affected by both the external environment and our own internal environment. Third, the same principles apply equally well to both environments. Fourth, radical behaviourists focus only on behaviour and the variables that control it. They look in only two places for these variables: the conditions that immediately precede the behaviour and the conditions that immediately follow it. Imagine you are playing table tennis. As you hit the ball, you say to yourself, ‘Stay focused.’ You notice that the ball lands on the table more frequently when you do this. So this outcome (ball on the table) keeps you saying that phrase to yourself as you hit the ball. Consider what would happen if you said the phrase but the ball hit the net as often as it landed in play. Eventually you would stop saying the phrase to yourself.
There are two points to notice here:
1. It is the functional relationship between the outcome and the phrase that determines the likelihood that you will repeat the phrase.
2. The phrase itself has no power over the behaviour (it does not directly ‘cause’ the behaviour).
Radical behaviourism is sometimes viewed as simplistic, but Skinner’s approach was far from simple. In Science and Human Behavior he notes that behaviour is very complex and difficult to study: ‘Since it is a process, rather than a thing, it cannot be easily held for observation. It is changing, fluid, and evanescent, and for this reason it makes great technical demands upon the ingenuity and energy of the scientist’. Skinner focused on establishing laws of behaviour (empirical relationships between environmental events and behaviour) based on intensive observation of a single subject under carefully controlled experimental conditions. His approach, the experimental analysis of behaviour, investigated ‘operant’ behaviours – so-called because they ‘operate’ on the subject’s environment. Skinner viewed this approach as more representative of real-life learning. Operant behaviours are distinguished from the kind studied by Pavlov –‘respondent’ behaviours, which are a response to a known stimulus. Skinner’s classic work involved the study of bar pressing (or pecking) by rats (or pigeons) in a ‘Skinner box’ that was constructed to eliminate all extraneous stimuli. A hungry animal was placed in the box and allowed to explore it. Sooner or later the animal would accidentally press a lever that released a food pellet. The food acted as a reinforcing stimulus (or reinforcer) for the bar-pressing behaviour, increasing the probability of its future occurrence. In other words, the animal ‘worked’ (pressed the bar) because there was a ‘payoff’ (food). This is an example of operant conditioning. The manner in which the payoff occurred – the schedule of reinforcement – influenced bar pressing. Schedules of reinforcement could vary according to time interval schedules (in human terms, this might be the weekly pay check), or work ratio schedules (a pay cheque based, for example, on number of items sold). Ratio schedules produce greater rates of behaviour, or faster learning. Schedules can also vary in terms of whether they are fixed or variable. Interestingly, a variable ratio schedule, in which the rate of reinforcement of the rat varies somewhat according to the number of bar presses it makes, produces the highest rate of responding. Skinner went on to show that operant conditioning can take several forms. One of its first applications to human behaviour occurred in 1948 when it was used to treat an institutionalized, profoundly retarded person (Fuller, 1949). Systematic research to make the experimental analysis of behaviour useful in addressing human problems soon followed, giving rise to the widespread use of teaching machines (‘programmed learning’), behaviour modification in educational settings, and treatments for emotional and behavioural disorders.
The application of operant procedures to address socially important behaviours became known as applied behaviour analysis in the 1960s. Like Watson, who envisioned behavourism giving rise to ‘saner living’, Skinner saw his laboratory research as also providing a technology of behaviour that could improve society. In his novel Walden Two (1948), Skinner outlines in detail the mechanics of a society based on behavioural principles. Most modern behaviourists no longer adhere strictly to the behaviourism espoused by Watson or Skinner. But even psychologists who reject behaviourism in all its forms are indebted to it. The objective approach to understanding behaviour has its roots in structuralism and evolved though functionalism to reach its zenith in behaviourism. This is the hallmark of modern psychology.
Gestalt Psychology: (Connections)
While functionalism followed structuralism in the USA, and behaviourism arose in opposition to both, a different kind of opposition to structuralism emerged in Germany – Gestalt psychology. The Gestalt attack on structuralism in Europe was independent of the opposition that had developed in the USA. It arose out of a simple observation by its founder, Max Wertheimer (1880–1943), whose paper ‘Experimental studies of the perception of movement’ marks the beginning of Gestalt psychology. Wertheimer notes that we can see motion or movement even when no actual movement takes place. For example, when two lights flash in quick succession, we see what appears to be movement from one to the other and back again. Wertheimer called this the ‘phi phenomenon’.
It was impossible to explain the phi phenomenon in structuralist terms by describing each elementary sensation (any more than we can explain a melody by describing each individual note). So how did Wertheimer explain it? He did not. He saw no need for explanation, for, he argued, apparent movement could not be reduced to anything simpler. From the Gestalt perspective, the perception forms a whole (in German, Gestalt means ‘form’ or ‘entire figure’), or unity (the movement), that is greater than the sum of its parts (the two lights). Gestalt psychology therefore challenged the associationist views that prevailed at the time. Gestalt psychology is based on the principles that complex mental experience exists on its own, and that perception is composed not of elements but of structured forms. Perhaps the best known Gestalt psychologist, Wolfgang Kohler (1887–1967), reminds us that ‘the concept “Gestalt” may be applied far beyond the limits of sensory experience’. Kohler studied apes and observed that they solved problems (e.g. by joining two short sticks to retrieve a banana) by ‘insight’, or by spontaneously seeing relationships (in this case, between two sticks). This contrasted with the work of behaviourists, whom he criticized for structuring animal problem-solving tasks in such a way that they allowed only trial and error behaviour. For example, an animal in a maze cannot see the overall design of the maze, only the alley it is in, and it is therefore limited to using trial and error. Although it did not survive as a distinct school of psychology much beyond the 1950s, Gestalt principles were incorporated into other areas of psychology, particularly thinking and learning. It even influenced early social psychology.
Other School of Thoughts:
Many important developments in the emergence of psychology took place outside the context of the ‘schools’. he first began within a few years of the establishment of Wundt’s laboratory at Leipzeig.
Memory – [Hermann Ebbinghaus]
Shortly after Wundt stated that it was not possible to investigate higher mental processes experimentally, a compatriot, Hermann Ebbinghaus (1850–1909), devised ingenious experimental methods for studying memory (the process of learning and forgetting) using only himself as the subject. One experimental technique involved learning nonsense syllables – syllables that have no meaning and therefore no connections to anything in a subject’s experience. Ebbinghaus formed the syllables by using all possible combinations of consonants the test of time as his findings were later replicated by others and many remain valid today. According to Roediger (1999), Ebbinghaus solved three important problems faced by psychologists in their work:
1. converting unobservable mental processes into observable behaviour; 2. measuring the behaviour reliably; and 3. showing how relevant variables affect the behaviour. In doing so, he started a whole new field of study that remains vital today and set the stage for later study of many aspects of cognition.
Individual differences [ Francis Galton]
In addition to his remarkable work on memory, Ebbinghaus was the first to publish on intelligence testing in children. He developed a test, still included in test batteries today, which anticipated psychometrics, (psychometrics the theory and measurement of psychological variables such as IQ (intelligence quotient)) the theory and measurement of psychological variables. It was not until 1905, however, that Alfred Binet (1857–1911), along with fellow French researcher Théodore Simon, produced the first successful test of general intelligence. These efforts all rested on the earlier work of the Englishman Sir Francis Galton (1822–1910), who initiated the whole idea of ‘mental tests’. He assumed that intelligence could be measured in terms of sensory abilities, reasoning that the more the senses perceive differences – for example, the ease with which weights can be discriminated – the larger the field upon which our judgement and intelligence are able to act (Galton, 1928). Galton was also interested in the inheritance of mental abilities. Inspired by the work of his cousin, Charles Darwin, he did much to introduce the spirit of evolution to psychology.
His first influential work was Hereditary Genius (1869), which applies statistical ideas to the problem of heredity and documents the genealogy of 997 eminent men. Galton calculated that the chance (statistically) of members of this group having an eminent relative was less than 1 per cent. What he found was that 33 per cent had eminent relatives. His conclusion that genius is inherited would not be justified by today’s research standards. These would require his findings to be compared to those for a group of non-eminent men, and would require closer examination of an alternative hypothesis – namely, that relatives might share similar environments and not just genes. Galton’s interest in documenting human differences led him to develop statistical methods, perhaps the most famous of which is the correlation or ‘co-relation’ (Galton’s term) between two variables. Indeed, Galton’s pioneering work gave rise to a number of statistical tools that psychologists still use today. Two further, and better known, developments took place outside the mainstream of psychology – Sigmund Freud’s psychoanalysis and Jean Piaget’s genetic epistemology. Neither had an immediate impact on the subject, but over the course of time their influence was profound.
[Francis Galton (1822–1910) was instrumental in developingpsychometrics – the theory and measurement of psychologicalvariables. He reasoned that the more the senses perceive differences (for example, the ease with which weights can be discriminated), the larger the field upon which our judgement and intelligence are able to act. Inspired by the work of his cousin, Charles Darwin, Galton introduced the spirit of evolution to psychology. His first influential work, Hereditary Genius (1869), applies statistical ideas to the problem of heredity, documenting the genealogy of 997 eminent men. Galton’s interest in documenting human differences led him to develop statistical methods, perhaps the most famous being ‘co-relation’ – or correlation– between two variables.]
Psychoanalysis [Sigmund Freud]
Sigmund Freud (1856–1939), a Viennese physician, formulated a revolutionary theory of human behaviour. Although familiar with the experimental psychology movement, Freud’s data was not obtained from controlled experiments but by listening to patients who were not suffering from any familiar disease. He applied his own idiosyncratic interpretation of data to formulate theories. By the mid 1890s, he had become convinced that traumatic sexual experiences in childhood were responsible for many of his patients’ symptoms. These painful memories were pushed out of consciousness (‘repressed’) and the task of Freud’s ‘talking cure’ – psychoanalysis – [psychoanalysis Freud’s ‘talking cure’, which aimed to bring pathological memories into conscious awareness and was used by Freud as the foundation for developing a theory of personality] was to bring such memories into conscious awareness. Over the course of his career, Freud used psychoanalysis as the foundation for developing a theory of personality that included a number of mental structures – the id, ego and superego. These structures were fundamentally different from those investigated by Wundt. The id, together with portions of the ego and superego, were considered to be unconscious and therefore could not be analysed by introspection, and, unlike Wundt, Freud was also interested in the function of these structures. There were no points of contact between psychology and psychoanalysis. Each had a different approach, and psychologists were particularly critical of Freud’s methods, including the conditions under which he collected his data, the unstated process by which he moved from data to conclusions, vagueness of terms, and the difficulty of deriving empirically testable hypotheses.
Freud, for his part, simply stated that his work was ‘based on an incalculable number of observations, and only someone who has repeated those observations on himself and on others is in a position to arrive at a judgment of his own upon it’. But because no one knew how Freud reached his judgements, they could not be repeated. Eventually even his own disciples grew frustrated and split from him. Subsequent attempts to describe the dynamics of the mind that build on psychoanalytic thinking are generally referred to as psychodynamic theories. Although psychoanalysis never became a ‘school’ in psychology (its home always was and remains in freestanding psychoanalytic institutes outside academia), many of his concepts came to have a profound influence on psychology, and on twentieth century civilization in general.
Genetic epistemology [Jean Piaget]
How do we come to know something? This is the question addressed by the branch of philosophy concerned with the study of knowledge – epistemology [genetic epistemology the study of the origin of knowledge in child development, as practised by Jean Piaget] . Instead of using only logical arguments to address this question, a Swiss biologist, Jean Piaget (1896–1980), studied developmental changes in knowing and the nature of knowledge. Piaget did not identify himself as a psychologist, instead labelling his work as genetic epistemology, the study of the origin of knowledge in child development. Drawing on his work with fresh water molluscs, his greatest insight was simply that knowledge is a relationship between the knower and the known. The knower always provides a framework for the acquisition of knowledge, which simultaneously influences (assimilates) and is influenced by (accommodates) what is known. As the knower changes, so does what is known. Piaget argued that a child understands an object by acting on it either physically or mentally and thereby constructs knowledge. Infants develop cognitive structures or schemes, which are organized patterns of actions that reflect a particular way of interacting with the environment. Cognitive structures of older children, from about seven years on, reflect abstract mental operations. These operations, or internalized actions that are organized structures, allow older children to realize that quantities remain constant (are conserved) despite changes in appearance. Unlike behaviourists, Piaget ignored the issue of learning, which he long dismissed as ‘the American question’, and his theory of intelligence had little impact outside of Europe until John Flavell (1963) introduced Piaget’s work to the English-speaking world. Faced with the difficulty of Piaget’s writings and the scope of his work – which covered not only intelligence but also perception, language, play and such psychological processes as memory – it was all too easy for psychologists to focus only on aspects of the theory. Piaget considered this fragmentation the most common abuse of his work. And yet, even though much of his work was based on observation of his own children and has been criticized for relying too heavily on children’s verbal abilities to explain their understanding, it had a profound impact on developmental psychology. The most persistent and successful challenge to Piaget’s findings came from work inspired by a new approach to understanding cognitive processes.
Cognitive Revolution
It has been said that psychology ‘lost its mind’ with the advent of Watsonian behaviourism. It could equally be said that several factors led psychology to ‘regain its mind’, including the realization that:
1. the strict methodological controls that were part and parcel of behaviourism had resulted in the elimination of those concepts that related most closely to people’s everyday experience (e.g. their experience of consciousness);
2. the stimulus–response approach was inadequate for explaining many psychological phenomena (e.g. how language develops); and
3. behaviourism had thereby deprived psychology of some of its most interesting problems (e.g. how people ascribe meaning to events and how this meaning influences subsequent behaviour).
The ‘cognitive revolution’, which pushed behaviourism from its dominant position in psychology, cannot be traced to a founding figure or the publication of a particular paper. But many agree that Ulrich Neisser’s book Cognitive Psychology (1967) and Donald Broadbent’s work at the Applied Psychology Research Unit in Cambridge were important influences. Broadbent, in his work on human skills and performance (‘human factors’), noted that humans are guided by information, or ‘feedback’, provided by machines (e.g. instruments in
an aircraft cockpit), and that often the individual will no make use of all the information in operating the achine (flying the aircraft). The problem for the person operating the machine is the allocation of attention to direct the processing of available information. So, continuing our aircraft example, on different occasions it will be more relevant for the pilot to focus attention on the altimeter or the speed indicator, or to distribute her attention more widely across multiple sources of information. For example, both the altimeter and the speed dial may provide critical information during landing. Integrating this work with ideas from information theory – a branch of communications sciences that provides an abstract way of analysing the processing of knowledge – Broadbent id much to develop the human information-processing approach, which came to inform research in virtually all areas of modern psychology. Contemporaneous with Broadbent’s work was the emergence of the computer as a research tool. Computers gripped the imagination of psychologists, soon becoming a metaphor for mental functioning. They showed that complex actions can be broken down into a series of binary, yes-or-no decisions. In principle, this meant that, with a system of feedback, a computer could duplicate the behaviour of a human, no matter how complex that behaviour. These ideas quickly led to new models of behaviour that incorporated such mentalistic concepts as plans and goals. The information-processing approach is often described as an abstract analysis. This means that it does not focus on the operation of the physical components of the processing system – whether they be brain cells or digital switches. Both the brain and the computer consist of millions of components, yet the behaviour of computers can be understood by studying the programs that run them. In the same way, a good account of human behaviour is considered possible by using terms abstract enough to transcend the operation of the brain’s approximately 100 billion nerve cells.
From the human information-processing perspective, information delivered to the senses is translated into a cognitive code. In other words, specific aspects of the environment are detected and their organization begins. These are then delivered to working memory, a kind of workbench for cognitive codes where goals are established and a central processor comes into play. Two types of processing can occur: automatic processing, which is effortless and unconscious, and controlled processing, which is effortful and conscious. More recently, the computer metaphor has been challenged by the ‘brain metaphor’, which gave rise to the connectionist approach – also known as a ‘neural network’ approach, meaning that it is informed by a view of how the nervous system might compute things. Although largely interested in idealized nervous systems, connectionists do take pains to show that the human nervous system could process material in ways that are similar to their idealized systems. These systems conduct processing in parallel, not in the serial manner assumed in the information-processing approach. Connectionists also reject the idea of a central control unit – the notion of ‘boss’ neurons directing other neurons’ activities is foreign to connectionism – and argue that mental processes cannot be broken down into components. Instead, the neural and cognitive systems function as a whole. It is important to note that, while the cognitive revolution did not embrace biological explanations of behaviour, neither did it actively banish biology from psychology – unlike its behavioral predecessor. Startling new advances in the study of the nervous system have been made possible by technology, and neurobiologists (biologists who study the nervous system) can now study the brain in ways that were unimaginable just a couple of decades ago. Imaging techniques allow us to see the brain at work as it engages in various activities. It is also possible to measure brain activity in a very fine-grained manner, focusing on areas that might be as small as a few cubic millimeters. So far, these techniques have been applied to basic psychological processes such as reading, listening, remembering and experiencing emotion, and more recently to the study of social cognition (the processes involved in perceiving, interpreting, and acting on social information,
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