Cognitive Psychology History of Cognitive Psychology
History of Cognitive Psychology • Historical roots • Every epoch of human culture has wrestled with questions about human thought • Cognitive psych can be seen as specifically stemming from two different approaches to the study of human nature • Philosophy • Plato, Aristotle, Hobbes, Locke, Kant but also elsewhere around the world • Physiology • Hippocrates, Helmholtz • Its background within psychology goes back to the foundation of psychology itself • Wundt, James, later Gestalt psych • As such, the history of cognitive psychology is much the history of psychology itself
Historical roots • The logical progression of ideas • Hegelian dialectic • Thesis • Antithesis • Synthesis • Current beliefs are challenged by alternatives, leading to new theories that stem from the old
Historical Roots • Plato • Reality in abstract forms, physical world composed of imperfect copies • Rationalist approach to understanding • Using logic to understand the world • Aristotle • Knowledge can be obtained through experience and observation • Set the stage early on for a physiological psychology • Hippocrates • Let’s open it up and see inside! • Disease not the result of divine musings
Historical roots • Key concepts arising early on: • The mind-body connection • Monism vs. Dualism • Innate vs. Acquired abilities • Rationalism vs. empiricism
Historical roots • After a strong start the study of human behavior and thought did not progress much • Up through the middle ages it could be said most were much more interested in the afterlife than life itself • Basis for understanding were the scriptural accounts of phenomena • Arguments had to support what was already accepted in terms of faith, contradictions to established ideas were unacceptable
Historical roots • The Renaissance • Renewed interest in humankind (specifically its abilities, not in the sense of helping our fellow man) and the here and now • Birth of science • Observation and measurement key in understanding ourselves
Historical roots • Beginnings of the modern period • Descartes • Poster child for dualism • Mind and body are separate but do interact (pineal gland) • Locke • Mind as a Tabula rasa on which experience writes
Historical roots • James Mill • Associationism • Reductionism • Laws of physical universe explain what we see • Complex ideas can be seen as associations of much simpler ones • Kant • Synthesis of empiricist and rationalist approaches • Some knowledge is innate and independent of experience while other knowledge requires it • Understanding may be had from a synthesis of the two
Modern Foundations • Important aspects of 19th century psychology • Beginnings of scientific investigation • Fechner’s Elemente der Psychophysik 1860 • Focus on mental processes • Structure, function, purpose (adaptive value) • Helmholtz • Considered to be one of the greatest scientists of the 19th century because of his contributions to the fields of physics, physiology, and eventually psychology • Among many of his contributions was that he showed that measuring the speed of nerve conduction was possible • Previously thought that the nonmaterial agent moved instantaneously • Paved the way for the emergence of experimental psychology • Thus it is only in the last 150 years was it believed that human cognition could even be studied, though the research could have begun much sooner, even hundreds of years earlier • E.g. simple recall studies under various conditions
Wundt and the founding of scientific psychology • Late 1800s Wundt establishes first experimental psychology lab • Introspection as main tool of psychology early on • In many cases highly trained observers reported the contents of their own consciousness • Focus primarily on elements of sensation and feeling • The immediate experience, study human consciousness as it occurs • Not simply breaking aspects of experience down into its constituent parts, but rather a study of processes and the dynamical nature of cognition* • Full circle? Dynamical Cognitive Science *Wundt was not a structuralist in the sense his student Titchener was. Cognition was more than the sum of its parts.
Wundt and the founding of scientific psychology • His experimental introspection was not the unstructured self-observation used by earlier (and some later) philosophers/“psychologists” • Pure introspection • Wundt’s introspection used laboratory instruments to present stimuli, in most instances the subject was to respond with a simple response such as saying “yes” or “no”, pressing a key • Experimental introspection
Wundt and the founding of scientific psychology • Some of Wundt’s students • Cattell • Titchener • Witmer • Munsterberg • Spearman • Hall
Modern Foundations • James’ pragmatism and the beginnings of functionalism (Darwin, Cattell, Galton, Hall) • Reaction to Wundt (or rather, Titchener’s interpretation of him) • How do cognitive processes work and what might be their purpose? • Stress the function of mental process rather than contents (elements) • Concern for practicality, emphasis on the individual, and evolutionary theory
James and the stream of consciousness • “The traditional psychologist talks like one who would say a river consists of nothing but pailsful, spoonsful, quartpotsful, barrelsful and other molded forms of water. Even were the pails and pots all actually standing in the same stream, still between them the free water would continue to flow.” • In opposition to those searching for mental elements, he believed that: • Consciousness is personal, reflected the experience of the individual. • It is continuous • It is constantly changing, therefore we can never have the exact same idea twice (Heraclitus) • It also cannot be divided up for analysis • Finally it is selective, and most importantly functional
Modern Foundations • James’ approach was mostly philosophical and incorporated ‘armchair’ introspection • Other labs were established here and abroad and had different varieties of introspection such that, at the turn of the century, we had several groups reporting findings mostly a reflection of their method than of substance
Modern foundations • Backlash to introspectionism • Not everything is available to consciousness • How can you describe the experience while still engaged in it? • Even if one could describe accurately what you are experiencing, how did one come to that conclusion? • Enter Behaviorism • I got your science right here! (Pavlov, Watson, Skinner) • Cut the fluff! Stick to the observables!
Behaviorism • The shift in American psychology from the essentially German emphasis on the study of the processes and elements of cognition to a primary focus on behavior was initiated by John Watson • “Let us limit ourselves to things that can be observed,and formulate laws concerning only those things.Now what can we observe? We can observe behavior- what the organism does or says.” • The immediate predecessors of behaviorism, however, were Russian physiologists and reflexologists (Pavlov etc.)
Behaviorism • Classical Conditioning • Conditioned reflex • Operant Conditioning • Pos/Neg reinforcement • Punishment • Changed the perspective to that of prediction and control of behavior rather than states of consciousness • No reference to mental events, though the less radical types would at least acknowledge them
Problems with behaviorism • Difficulty in explaining complex learning • Nomothetic application too simplistic and problematic • Assumed that learning was the same for all individuals (relatively the same across species)
Problems with behaviorism • Even early on cognition was acknowledged by some, and problems were present • Rats that had no prior reinforcement performed just as well as those that had once they received it themselves (Blodgett 1929) • Learning had occurred in the absence of reinforcement • Tolman • “Cognitive maps of Rats and Men” • Understood that cognitive process did exist and influenced behavior – referred to them as intervening variables – variables that intervene between environmental events and behavior
Problems with behaviorism • Later on, the inefficiency of behaviorism’s account of language processing proved to be a major shortcoming • Chomsky’s critique of Skinner’s Verbal Behavior • Picture is worth 10,000 responses • Mouses (overgeneralization of internal grammatical rules) after initial correct learning, even if never heard before • Appropriate responses to novel stimuli • Gist: language cannot be explained sufficiently without reference to mental events.
Other perspectives: Psychoanalysis • Freud • Existed • Now he doesn’t • Moving on…
Psychodynamic Theory • Motivation, unconscious, wish-fulfillment etc. • The primary stimulus of interest is thus a hidden one for the most part • Contrast with behaviorists and cog psych • Relied more on speculation rather than observation (others on the other hand must be able to explain results in light of previous research)
Other perspectives: Gestalt Psychology • Gestalt psychology was a German movement that directly challenged ‘Wundt’s’ structural psychology • Though again Wundt was not a structuralist in the sense that Titchener was • The goals of Gestalt psychology were to investigate the organization of mental activity and to determine the exact nature of the person-environment interactions • Gestalt psychology emphasized the ‘how’ of mental processing, rather than the ‘what’
Gestalt Psychology • Cognitive processes not so easily reduced to elements • Active perception • Example: where is the square coming from?
Gestalt Psychology • Wertheimer, Koffka, Köhler • Wertheimer • Phi phenomenon (apparent movement) • Illusion that a light is moving from one location to another • Phi phenomena cannot be reduced to the stimulus elements presented to the subjects – the subjective experience of motion is the result of a dynamic interaction between an observer and the stimuli • Köhler • Insightful chimpanzees • Koffka • Perhaps most vocal and prolific proponent of gestalt principles
Gestalt Psychology • Major aspects of perception • Similarity • Proximity • Closure
Gestalt Psychology • Gestalt psychology grew out of the research on sensory and perceptual processes, providing also an alternative to early behaviorism • Seeing the salient features of shapes and forms on a background within a perceptual field is an innate activity and not an acquired skill • Organization leading to meaning, then, is the key to our perceptual structure • ‘Learning takes’ place as a result of psychological disequilibrium or tension that persists until the problem is solved – insights are swift and free of errors • The Gestalt movement played a major role in providing a contrast to behaviorism by broadening its basis to foster a more complete view of the learning process.
Modern Foundations • But… • How do we study it scientifically? • Powerful demonstrations, but not too much in the way of theory • Also… • A little too nativistic: focus on perception primarily based on what we bring to the table • Experience, expectation can affect perception • And… • Who is that short guy over there with the funny mustache?
1950s • Behaviorism had been dominating American ‘psychological’ study for decades • While there were pockets of ‘resistance’ much of the work as far as cognition was concerned was abroad • By the 1950s however, the scientific climate in psychology had changed
1950s • (Re)Enter cognitive psychology • From Neisser 1967 • “Cognition refers to all the processes by which the sensory input is transformed, elaborated, stored, recovered, and used… sensation, perception, imagery, retention, recall, problem-solving and thinking, among many others, refer to hypothetical stages or aspects of cognition” • Cognitive Psychology is the domain of psychology involved in the scientific analysis of mental processes in order to better understand behavior
Information processing approach • With the advent of computing technology, a ready analogy was available to help understand how humans deal with and interact with their environment • Key work ushering in the information processing approach: • Broadbent, Perception and Communication, (1958) • Current incarnations: Computational mind (Daniel Dennett), Computational Universe (Seth Lloyd) • Obviously the brain does not work like a computer, however both are involved in the processing and storage of information
Information processing approach • Neisser (1967) • Provided a summary of the approach up to that time • Also provided a blueprint for research • Indirect studies of cognitive processing • Example: Reaction time studies • A central tenet of this approach is that information is processed and stored in stages • Atkinson & Shiffrin (1968) • Short-term, Long-term memory • Craik & Lockhart (1972) • Levels of processing
Current information processing models • Connectionism • Later models de-emphasized the serial nature of the original information processing model • Information processed in parallel across regions of the brain • Flexible, able to adapt to experience • Models were provided that simulated performance though might not have explicit physiological underpinnings • Rummelhart & McClelland (1986)
Info processing takes place through the interaction of a large number of simple processing elements (units) sending excitatory and inhibitory information
Other areas: Artificial Intelligence • Further development of the computer brought on attempts to mimic the way the mind thinks • Newell & Simon: The logic theorist • Turing test (as yet, not passed)
Information processing approach • Although the information processing approach and computer analogy has been extremely enlightening, it does have problems • Although computers can place chess and perform other tasks similar to or even better than humans, still pale in comparison to typical brain functioning • Quantum computing? • No real physiological correspondence to computer parts • Memory as a function also (not just a storage device) • However the information processing perspective remains the heart of cognitive psychology
Levels of explanation • From Marr (1982) • Functional • What is the goal and purpose of the processing? • Representational • How is the information represented within the system? • Physical • How is the processing physically realized? • One can perhaps add to or rephrase (the demarcation in actual research may blur), but the levels are particular to the info-processing approach
Cognitive Psychology Today • Today cognitive psychology encompasses myriad approaches to studying a wide variety of mental processes • The term cognitive science is often used to note the interdisciplinary study of cognition Miller’s conceptualization (late 70s), though now would suggest links among all of them
Complexity is key • The amazing thing about thought is that everything is too complicated for us to do • Yet, we manage to get around the world. • What do we mean by complexity? • There are always many possibilities • Only a few of them are relevant • How do we decide which ones are correct?
Complexity • Somehow we manage to solve these problems, so what must happen? • We must limit the options we consider • We must think quickly enough to consider a reasonable number of options • How does this happen? • The cognitive system has many ways of focusing on what is relevant • Constraints promote information likely to be relevant • Some possibilities may be missed • Constraints determine what is easy or hard to do • Theories suggest possible sets of constraints • Experiments test whether people use those constraints. • Return to levels of explanation • Theories may describe constraints at different levels of explanation • Computational level • Algorithmic level • Implementational level • Different kinds of data will be relevant to each type of explanation
Basic Mechanisms and Issues • The cognitive system is the primary survival mechanism for the human species. • And as we have been discussing we could say the cognitive system works mainly on two principles • Meaning • Extract a mental model of environment (functional) • Cognitive Economy
Basic Mechanisms and Issues • Association • Contiguity in space and time • Functional (causal) associations • Organization of knowledge • Skill/ acquisition • Learning • Power law of practice
Basic Mechanisms and Issues • Judgment/Decision making • Cognitive development • Attention/perception • How do we take info from the outside in mangled form, and put it back together for conscious experience and behavior?
Methods of Investigation • Behavioral • Neuropsychological • Brain Imaging • Event-related Potentials • Positron Emission Tomography • Functional Magnetic Resonance Imaging
Methods of Investigation • Behavioral data • Simple observation • Reaction time, paired-associate learning, accuracy measures, free recall etc. • Indirect measure of cognition, but most widely used
Methods of Investigation • Lesion Studies • Studying brain damage can tell us something about what areas of the brain affect particular functions • If an area has a lesion, and the person shows a specific deficit, then that area probably has somethingto do with that function. • Example: Memory disorders • Lesions of the hippocampus and memory
Methods of Investigation • Brain Imaging • ERP • Bad spatial/Good temporal resolution • Look at polarity, amplitude, latency and distribution
Methods of Investigation • PET and fMRI • Pretty pictures • Good localization • Not as good temporal resolution, very expensive • fMRI • Face processing (head on view) • PET scan • Normal left, Alzheimer’s right