A Transition to Modern Cognitivism: Hebb, Tolman, and the
Psychology of Learning
Hebb’s theory: Higher Mental Processes
Higher mental processes are activities that mediate responses; processes that link stimuli and responses, sometimes over long periods; experienced as “thinking.”
Hebb suggested that inferences about such processes might be useful if they are based on actual observations.
Hull also suggested importance of intervening variables between S and R; Hebb’s variables are physiological and based on neurological fact and speculation
Physiology of Learning
Since psychology deals with biological organisms, it should also be concerned with humans as products of evolution, as well as functioning of glands, muscles, and other organs.
Hebb believed psychology needs to take into account functioning of the nervous system, particularly the brain.
Skinner believed speculations about CNS are fictions; deal with conceptual rather than central nervous system.
Hebb chose to speculate about what he labeled “the conceptual nervous system”
Hebb described his theory as pseudobehavioristic because it primarily explains thought processes and perception.
Central Nervous System (CNS)
CNS consists of billions of cells called neurons – specialized cell whose function is to transmit impulses in the form of electrical and chemical changes.
Bundles of neurons form nerves.
Neurons consist of:
one is the axon, a conductor of neural impulses
axons may be microscopically short or as long as a meter
near ends, axons branch out and terminate in a number of little bulbs called terminal boutons or synaptic knobs, which end close to other neurons
The gap between the terminal bouton and an adjacent neuron is a synaptic cleft.
Transmission of impulses within and between neurons involves both electrical and chemical activity.
A series of chemical changes brought about by stimulation change the electrical potential of the cell, causing a flow of charged particles, called ions.
This flow is an electrical impulse, called action potential (vs. resting potential).
Within approx. 2 milliseconds, the neuron regains resting potential, but for a brief period (refractory period) it is discharged.
Chemicals involved in changing the electrical potential of cells, thus leading to neural transmission, are called neurotransmitters; > 100 have been identified.
dopamine = functioning of neurons associated with pleasure and reinforcement; important neurotransmitter for motivation
norepinephrine (noradrenaline) = linked with arousal, as well as memory and learning
Acetylcholine = activating the muscles, leading to movement; involved in learning and memory also
Serotonin = in much of the brain, especially those related to emotion; low levels are linked with depression, aggression, and violence
Repeated transmission of impulses between 2 cells (or neurons) leads to permanent facilitation of transmission between these cells, or learning.
Neural cells may be reactivated repeatedly because of their own activity, resulting in a circular pattern of firing called a cell assembly.
If a number of related cell assemblies are simultaneously active, they too will become linked in what Hebb labels a phase sequence.
Recognition of even very simple objects, like colors or sensations, will involve the activation of a large number of such cell assemblies or phase sequences.
Neurological Changes Underlying Learning
Cell assemblies and phase sequences are hypothetical constructs, but recent evidence suggests that brain cells tend to fire in groups (assemblies) and to reactivate each other, just as Hebb suggested.
Habituation – when response to a stimulus stops; evidence that learning has occurred.
In some instances, repeated stimulation leads to sensitization, the opposite of habituation; in this case, a slight stimulation causes measurable response.
Reactivity and Plasticity
Reactivity refers to the capacity of an organism to react to external stimuli.
Plasticity is the capacity to change as a function of experience, or repeated stimulation.
Sensitization leads to long-term potentiation (LTP), a lasting increase in the responsiveness of neurons.
Habituation leads to long-term depression (LTD), a lasting decline in the responsiveness of relevant neurons.
Hebb rule: If input from neuron A contributes often enough to firing of neuron B, then the synapse from A to B will change and become stronger.
Hypotheses and Assumptions
Basic hypothesis: Mediation, or thinking, consists of “activity in a group of neurons, arranged as a set of closed pathways that will be referred to as a cell assembly, or of a series of such activities, which will be referred to as a phase sequence” (Hebb, 1958, p. 103).
Assumption 1: A cell assembly, or mediating process, is established as the result of the repeated firing of cells; repetition thus has a facilitating effect on further neural activity.
Hypotheses and Assumptions (cont.)
Assumption 2: If two cell assemblies are repeatedly active at the same time, an association between the two will tend to form.
Assumption 3: An assembly that is active at the same time as an efferent pathway (a neural pathway leading outward from the CNS) will tend to form an association with it.
Assumption 4: Each assembly corresponds to relatively simple sensory input.
Learning and Thinking
mediation = thinking; activity in assemblies of neurons
The nature of mediation is determined by the specific assemblies involved.
Hebb believed the activated area of the cortex, rather than the nature of the neural activity itself, determines the subjective experience of the organism.
What Hebb labels a phase sequence is a neurological unit where the transmission of impulses has become so easy that the activation of one part of the sequence is sufficient to activate the entire organization.
Higher processes involved in learning are assumed to involve the combination of phase sequences in higher organizational units, supraordinate phase sequences
Set and Attention
A set is a predisposition to respond in a certain way; selectivity among responses.
Attention is a predisposition to allow influence of certain stimuli; selectivity among input.
Both set and attention are functions of the preactivation of specific cell assemblies;
Example: When racers are told to get ready to run, they are set to respond by running when they hear a bang; when they are paying attention to the impending sound, they are less likely to attend to other distracting stimuli.
Set and attention are important for teachers; attention, for learning to occur and set, for choosing appropriate responses.
Arousal = alertness of an individual reflected in physiological measures such as heart and respiration rate and brain wave activity; too high = anxiety, too low = lethargy
Arousal level is largely a function of the amount and variety of stimulation to which an organism is exposed.
Repetition leads to repeated activation of same sets of neurons; establishment of these patterns defines learning.
Serves as a transition between behavioristic and more cognitive theories.
brought consideration of physiological mechanisms back into the study of learning and behavior
gives him an important position as a motivational theorist
work on sensory deprivation has had important influence on research in learning by calling attention to curiosity, novelty, and exploration.
Hebb’s theory reflects facts well.
Current knowledge about neurological transmission supports Hebb’s assumptions.
Behaviorism to Cognitivism
Change from first Behaviorists to current cognitive psychologists happened slowly as a result of Hebb, Tolman, and others’ influence.
It isn’t the mind but observable behaviors that should be the target of the science of psychology.
On the other hand, the subject matter of psychology is mental activity itself, and that it can be studied directly.
Hebb was a neobehaviorist in that he included mental processes of thinking and imagining.
Tolman was a neobehaviorist in that he gave behaviorism a purpose.
Mechanistic behaviorism includes theories that emphasize predictable or machinelike aspects of human behavior
Reductionist or molecular theories explain behavior by analyzing it at the molecular level.
Molar theories assume behavior could be understood as a whole without being reduced to its individual components
Tolman’s Purposive Behaviorism
Tolman believed that all behavior has a purpose, and all actions are directed toward some goal by cognitions.
cognitions = intervening variables tied to observable behaviors; abstractions that should only be inferred from behavior, not through introspection
A cognitive map is an internal representation of relationships between goals and behaviors as well as knowledge of the environment.
Education Implications and Summary Principles
Behavior is purposive.
All behavior is guided by expectancies, which are related to goals.
Teachers need to find ways to influence expectancies and guide students’ goals and expectations.
Behavior is cognitive.
Cognitions, knowledge of a link between stimuli and expectancies of acquiring a goal, develop after experiences with stimuli and rewards.
Teachers should arrange for students’ most desirable behaviors to be followed by positive outcomes.
Reinforcement establishes and confirms expectancies
Expectancies develop in situations where reinforcement is possible, and role of reinforcement is confirming expectancies.
To the extent that teachers control and influence students’ environments, they can influence learning and behavior.
A theory of purposive behaviorism is molar.
Purpose, a single, unified goal, directs behavior.
Links stimuli with expectancies rather than reinforcement or responses.
Less mechanistic, less rigid, view of the learner; learner is thoughtful being.
Though behaviorism and cognitivism birthed at same time and both still exist, behaviorism dominated during 1920s to mid-century, and cognitivism began to dominate around mid-century.
Tolman’s theory was transitionary into more cognitive theories.
Contributed to importance of maze learning in terms of cognitive mechanisms and memory.
Somewhat inconsistent or unclear in terminology.
Tolman’s views reflect both behaviorism and cognitivism.
Gestalt means “whole;” the whole is greater than the sum of its parts.
Kohler observed apes solving problems by stopping, possibly thinking, and carrying out correct reactions in one consecutive whole.
The cornerstone of Gestalt psychology is insight, the perception of relationships among elements of a problem situation.
Insight is a type of relational thinking, in that it requires a mental reorganization of problem elements and recognition of the correctness of the new organization.
Insight is not a “special” quality but applies to understanding common facts and solving general, everyday problems.
Only through an understanding organization or structure do people know things; organizing what is perceived is much more important than trial and error.
Behavior cannot be understood through its parts; it cannot be reduced to isolated sensations or to isolated stimuli and responses.
Gestalt Theory: The laws of Perception
Pragnanz: Good form
Insightful solutions often seem to involve an “abrupt reorganization of given materials, a revolution, that suddenly appears ready-made on the mental scene”
The brain appears to be directed by a tendency for whatever is perceived to take the best form possible.
Principle of closure: the act of completing a pattern.
Principle of continuity: perceptual phenomena tend to be perceived as continuous
Principle of similarity: objects that are similar tend to be perceived as related.
Principle of proximity: objects or perceptual elements tend to be grouped by their proximity
Learning and Memory
Learning results in the formation of memory traces.
Learned material, like any perceptual information, tends to achieve the best structure possible relative to the laws of perceptual organization.
What is remembered is not always what was learned or perceived, but it is often a better gestalt than the original.
Organizational tendencies of memory:
Leveling = a tendency toward symmetry or toward a toning down of the peculiarities of a perceptual pattern.
Sharpening = the act of emphasizing the distinctiveness of a pattern; qualities that most clearly give an object identity in one’s memory tend to be exaggerated in reproducing that object.
Normalizing = the reproduced object is modified to conform with previous memories
Not the world as described by physics, but the world as individually perceived (of “direct experience”) is far more important for understanding the individual’s behavior.
The behavioral field is the actor’s personal view of what is real.
appearance vs. reality: what people see is not necessarily what is really there; to understand behavior, it’s necessary to know something of the individual’s perception of reality (behavior or psychological field).
Because the psychological field includes people’s individual perceptions of other people, this approach lends itself more easily to understanding social behavior.
Gestalt psychology is considered the beginning of contemporary cognitive psychology because:
of its concern with perception, awareness, problem solving and insight.
it rejected behaviorism for being overly mechanistic, incomplete, and unsuitable for explaining higher mental processes.
difference with contemporary cognitive psychology:
Gestalt psychology used animals in research frequently and deals mainly with problems of human perception.
Contemporary cognitivism deals with problem solving, decision making, information processing, and understanding, studying mostly humans in topics such as understanding prose, memory for words, paraphrasing, language learning, and reading.
Learning situations should be structured in such a way that learners can eventually achieve insight.
Problems selected for presentation to a learner should not be problems that can be solved by memorizing a series of steps.
Problems should be presented in meaningful, real-life situations so that learners can see their importance and their relationship to real, day to day problems.
Learners need to be encouraged to understand the problem rather than to attempt to copy a set of prescribed procedures.
Guidance from teachers should help students discover solutions for themselves, achieve their own insight, rather than imparting all information and procedures from teacher to student.
Employment of constructivism, rather than direct learning
constructivist = highly learner-centered and reflect the belief that meaningful information is constructed by learners rather than given to them.
Direct teaching = teacher-centered approaches
Theoretical ideas were vague and not useful for predicting or explaining behavior. (ex. “parts” sometimes mean specific units of perceptual analysis but at other times refer to physiological or neural activity in the brain).
Provided useful applications in counseling and therapy, such as Rogerian (uses terms phenomenological and phenomenal field instead) which emphasizes understanding behavior by considering a person’s personal view.
Contributed significantly to development of later cognitive theories; served as basis for contemporary cognitive theory.