Stimulus (psychology)

Last updated

In psychology, a stimulus is any object or event that elicits a sensory or behavioral response in an organism. In this context, a distinction is made between the distal stimulus (the external, perceived object) and the proximal stimulus (the stimulation of sensory organs). [1]

Contents

History

The study of the stimulus in psychology began with experiments in the 18th century. In the second half of the 19th century, the term stimulus was coined in psychophysics by defining the field as the "scientific study of the relation between stimulus and sensation". This may have led James J. Gibson to conclude that "whatever could be controlled by an experimenter and applied to an observer could be thought of as a stimulus" in early psychological studies with humans, while around the same time, the term stimulus described anything eliciting a reflex in animal research.

In behavioral psychology

The stimulus concept was essential to behaviorism and behavioral theories of B. F. Skinner and Ivan Pavlov in particular. Within such a framework several kinds of stimuli have been distinguished.

Sequential illustration of Pavlov's dog experiment Pavlov's dog conditioning.svg
Sequential illustration of Pavlov's dog experiment

In the theory of classical conditioning, unconditioned stimulus (US) is a stimulus that unconditionally triggers an unconditioned response (UR), while conditioned stimulus (CS) is an originally irrelevant stimulus that triggers a conditioned response (CR). Ivan Pavlov's dog experiment is a well-known experiment that illustrates these terms. The unconditioned stimulus is the dog’s food that would naturally cause salivation, which is an unconditioned response. Pavlov then trained the dog by ringing the bell every time before food. The conditioned stimulus is the ringing bell after training, which causes salivation as a conditioned response. [3] [ page needed ]

Moreover, an eliciting stimulus was defined as a stimulus that precedes a certain behavior and thus causes a response. A discriminative stimulus in contrast increases the probability that a response will occur but does not necessarily elicit the response. A reinforcing stimulus usually denoted a stimulus delivered after the response has already occurred; in psychological experiments, it was often delivered on purpose to reinforce the behavior. Emotional stimuli were regarded as not eliciting a response; instead, they were thought to modify the strength or vigor with which a behavior is carried out. [4] [ page needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Ivan Pavlov</span> Russian physiologist (1849–1936)

Ivan Petrovich Pavlov was a Russian and Soviet experimental neurologist and physiologist known for his discovery of classical conditioning through his experiments with dogs.

Operant conditioning, also called instrumental conditioning, is a learning process where behaviors are modified through the association of stimuli with reinforcement or punishment. In it, operants—behaviors that affect one's environment—are conditioned to occur or not occur depending on the environmental consequences of the behavior.

Classical conditioning is a behavioral procedure in which a biologically potent physiological stimulus is paired with a neutral stimulus. The term classical conditioning refers to the process of an automatic, conditioned response that is paired with a specific stimulus.

The experimental analysis of behavior is a science that studies the behavior of individuals across a variety of species. A key early scientist was B. F. Skinner who discovered operant behavior, reinforcers, secondary reinforcers, contingencies of reinforcement, stimulus control, shaping, intermittent schedules, discrimination, and generalization. A central method was the examination of functional relations between environment and behavior, as opposed to hypothetico-deductive learning theory that had grown up in the comparative psychology of the 1920–1950 period. Skinner's approach was characterized by observation of measurable behavior which could be predicted and controlled. It owed its early success to the effectiveness of Skinner's procedures of operant conditioning, both in the laboratory and in behavior therapy.

Behaviorism is a systematic approach to understanding the behavior of humans and other animals. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent stimuli in the environment, or a consequence of that individual's history, including especially reinforcement and punishment contingencies, together with the individual's current motivational state and controlling stimuli. Although behaviorists generally accept the important role of heredity in determining behavior, they focus primarily on environmental events.

Habituation is a form of non-associative learning in which a non-reinforced response to a stimulus decreases after repeated or prolonged presentations of that stimulus. For example, organisms may habituate to repeated sudden loud noises when they learn these have no consequences.

A neutral stimulus is a stimulus which initially produces no specific response other than focusing attention. In classical conditioning, when used together with an unconditioned stimulus, the neutral stimulus becomes a conditioned stimulus. With repeated presentations of both the neutral stimulus and the unconditioned stimulus, the neutral stimulus will elicit a response as well, known as a conditioned response. Once the neutral stimulus elicits a conditioned response, the neutral stimulus becomes known as a conditioned stimulus. The conditioned response is the same as the unconditioned response, but occurs in the presence of the conditioned stimulus rather than the unconditioned stimulus.

Pavlov's typology of higher nervous activity was the first systematic approach to the psychophysiology of individual differences. Ivan Pavlov's ideas of nervous system typology came from work with his dogs and his realization of individual differences. His observations of the dogs led to the idea of excitation and inhibition in the nervous system, and Pavlov theorized that the strength of these processes in the nervous system will determine whether the subject will have a strong or weak nervous system. This theory has influenced research in the field of social psychology and personality.

<span class="mw-page-title-main">Blocking effect</span> Elaboration on classical conditioning in psychology

In Kamin's blocking effect the conditioning of an association between two stimuli, a conditioned stimulus (CS) and an unconditioned stimulus (US) is impaired if, during the conditioning process, the CS is presented together with a second CS that has already been associated with the unconditioned stimulus.

Comparative cognition is the comparative study of the mechanisms and origins of cognition in various species, and is sometimes seen as more general than, or similar to, comparative psychology. From a biological point of view, work is being done on the brains of fruit flies that should yield techniques precise enough to allow an understanding of the workings of the human brain on a scale appreciative of individual groups of neurons rather than the more regional scale previously used. Similarly, gene activity in the human brain is better understood through examination of the brains of mice by the Seattle-based Allen Institute for Brain Science, yielding the freely available Allen Brain Atlas. This type of study is related to comparative cognition, but better classified as one of comparative genomics. Increasing emphasis in psychology and ethology on the biological aspects of perception and behavior is bridging the gap between genomics and behavioral analysis.

Sensory preconditioning is an extension of classical conditioning. Procedurally, sensory preconditioning involves repeated simultaneous presentations (pairing) of two neutral stimuli, i.e. stimuli that are not associated with a desired unconditioned response.

Discrimination learning is defined in psychology as the ability to respond differently to different stimuli. This type of learning is used in studies regarding operant and classical conditioning. Operant conditioning involves the modification of a behavior by means of reinforcement or punishment. In this way, a discriminative stimulus will act as an indicator to when a behavior will persist and when it will not. Classical conditioning involves learning through association when two stimuli are paired together repeatedly. This conditioning demonstrates discrimination through specific micro-instances of reinforcement and non-reinforcement. This phenomenon is considered to be more advanced than learning styles such as generalization and yet simultaneously acts as a basic unit to learning as a whole. The complex and fundamental nature of discrimination learning allows for psychologists and researchers to perform more in-depth research that supports psychological advancements. Research on the basic principles underlying this learning style has their roots in neuropsychology sub-processes.

Psychological behaviorism is a form of behaviorism — a major theory within psychology which holds that generally human behaviors are learned — proposed by Arthur W. Staats. The theory is constructed to advance from basic animal learning principles to deal with all types of human behavior, including personality, culture, and human evolution. Behaviorism was first developed by John B. Watson (1912), who coined the term "behaviorism," and then B. F. Skinner who developed what is known as "radical behaviorism." Watson and Skinner rejected the idea that psychological data could be obtained through introspection or by an attempt to describe consciousness; all psychological data, in their view, was to be derived from the observation of outward behavior. The strategy of these behaviorists was that the animal learning principles should then be used to explain human behavior. Thus, their behaviorisms were based upon research with animals.

Counterconditioning is functional analytic principle that is part of behavior analysis, and involves the conditioning of an unwanted behavior or response to a stimulus into a wanted behavior or response by the association of positive actions with the stimulus. For example, when training a dog, a person would create a positive response by petting or calming the dog when the dog reacts anxiously or nervously to a stimulus. Therefore, this will associate the positive response with the stimulus.

The term conditioned emotional response (CER) can refer to a specific learned behavior or a procedure commonly used in classical or Pavlovian conditioning research. It may also be called "conditioned suppression" or "conditioned fear response (CFR)." It is an "emotional response" that results from classical conditioning, usually from the association of a relatively neutral stimulus with a painful or fear-inducing unconditional stimulus. As a result, the formerly neutral stimulus elicits fear. For example, if seeing a dog is paired with the pain of being bitten by the dog, seeing a dog may become a conditioned stimulus that elicits fear.

The memory system plays a key role in the decision-making process because individuals constantly choose among alternative options. Due to the volume of decisions made, much of the decision-making process is unconscious and automatic. Information about how a decision is made is remembered and used for future decisions. Memory is susceptible to biases, but it is integral to the formation of preferences and to differentiation between choices.

An antecedent is a stimulus that cues an organism to perform a learned behavior. When an organism perceives an antecedent stimulus, it behaves in a way that maximizes reinforcing consequences and minimizes punishing consequences. This might be part of complex, interpersonal communication.

Evaluative conditioning is defined as a change in the valence of a stimulus that is due to the pairing of that stimulus with another positive or negative stimulus. The first stimulus is often referred to as the conditioned stimulus and the second stimulus as the unconditioned stimulus. A conditioned stimulus becomes more positive when it has been paired with a positive unconditioned stimulus and more negative when it has been paired with a negative unconditioned stimulus. Evaluative conditioning thus refers to attitude formation or change toward an object due to that object's mere co-occurrence with another object.


Human contingency learning (HCL) is the observation that people tend to acquire knowledge based on whichever outcome has the highest probability of occurring from particular stimuli. In other words, individuals gather associations between a certain behaviour and a specific consequence. It is a form of learning for many organisms.

Association in psychology refers to a mental connection between concepts, events, or mental states that usually stems from specific experiences. Associations are seen throughout several schools of thought in psychology including behaviorism, associationism, psychoanalysis, social psychology, and structuralism. The idea stems from Plato and Aristotle, especially with regard to the succession of memories, and it was carried on by philosophers such as John Locke, David Hume, David Hartley, and James Mill. It finds its place in modern psychology in such areas as memory, learning, and the study of neural pathways.

References

  1. Hochberg, Julian E. (1964). Perception . Foundations of modern psychology series. Englewood Cliffs, NJ: Prentice-Hall. p.  13. OCLC   193307.
  2. 1 2 3 Gregory, Richard L., ed. (1987). "Stimulus" . The Oxford Companion to the Mind . Oxford; New York: Oxford University Press. p.  748. ISBN   019866124X. OCLC   17227958.
  3. Pavlov, Ivan Petrovitch (1941). Conditioned reflexes and psychiatry . Lectures on conditioned reflexes. Vol. 2. New York: International Publishers. OCLC   8586636.
  4. Skinner, B. F. (1938). "The behavior of organisms; an experimental analysis" . The Century psychology series. New York; London: D. Appleton-Century Company, Inc. OCLC   553295.