In
psychology
Psychology is the scientific study of mind and behavior. Its subject matter includes the behavior of humans and nonhumans, both consciousness, conscious and Unconscious mind, unconscious phenomena, and mental processes such as thoughts, feel ...
, 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).
*In
perceptual psychology
Perceptual psychology is a subfield of cognitive psychology that concerns the conscious and unconscious innate aspects of the human cognitive system: perception.
A pioneer of the field was James J. Gibson. One major study was that of affordances ...
, a stimulus is an energy change (e.g., light or sound) which is registered by the
sense
A sense is a biological system used by an organism for sensation, the process of gathering information about the surroundings through the detection of Stimulus (physiology), stimuli. Although, in some cultures, five human senses were traditio ...
s (e.g., vision, hearing, taste, etc.) and constitutes the basis for
perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...
.
*In
behavioral psychology
Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that behavior is either a reflex elicited by the pairing of certain antecedent (behavioral psychology), antecedent stimuli in the environmen ...
(i.e.,
classical and
operant conditioning), a stimulus constitutes the basis for
behavior
Behavior (American English) or behaviour (British English) is the range of actions of Individual, individuals, organisms, systems or Artificial intelligence, artificial entities in some environment. These systems can include other systems or or ...
.
The
stimulus–response model
The stimulus–response model is a conceptual framework in psychology that describes how individuals react to external Stimulus_(psychology), stimuli. According to this model, an external stimulus triggers a reaction in an organism, often without ...
emphasizes the relation between stimulus and behavior rather than an animal's internal processes (i.e., in the
nervous system
In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...
).
*In
experimental psychology
Experimental psychology is the work done by those who apply Experiment, experimental methods to psychological study and the underlying processes. Experimental psychologists employ Research participant, human participants and Animal testing, anim ...
, a stimulus is the event or object to which a response is measured. Thus, not everything that is presented to participants qualifies as stimulus. For example, a
cross mark at the center of a screen is not said to be a stimulus, because it merely serves to center participants' gaze on the screen. Also, it is uncommon to refer to longer events (e.g. the
Trier social stress test
The Trier social stress test (TSST) is a laboratory procedure used to reliably induce stress in human research participants. It is a combination of procedures that were previously known to induce stress, but previous procedures did not do so rel ...
) as a stimulus, even if a response to such an event is measured.
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
Psychophysics is the field of psychology which quantitatively investigates the relationship between physical stimulus (physiology), stimuli and the sensation (psychology), sensations and perceptions they produce. Psychophysics has been described ...
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 biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus.
Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...
in animal research.
In behavioral psychology
The stimulus concept was essential to
behaviorism
Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that behavior is either a reflex elicited by the pairing of certain antecedent stimuli in the environment, or a consequence of that indivi ...
and behavioral theories of
B. F. Skinner and
Ivan Pavlov in particular. Within such a framework several kinds of stimuli have been distinguished.
In the theory of
classical conditioning
Classical conditioning (also respondent conditioning and Pavlovian conditioning) is a behavioral procedure in which a biologically potent Stimulus (physiology), stimulus (e.g. food, a puff of air on the eye, a potential rival) is paired with a n ...
, ''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.
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.
See also
*
Sensory cue
In perceptual psychology, a sensory cue is a statistic or signal that can be extracted from the Sense, sensory input by a perceiver, that indicates the state of some property of the world that the perceiver is interested in perceiving.
A ''cue'' ...
*
Stimulation
Stimulation is the encouragement of development or the cause of activity in general. For example, "The press provides stimulation of political discourse." An interesting or fun activity can be described as "stimulating", regardless of its physic ...
References
{{DEFAULTSORT:Stimulus (Psychology)
Behavioral concepts
et:Stiimul
eo:Stimulo
ru:Раздражитель