Conditioned Stimulus


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Conditioned Stimulus

 

a signal that causes a conditioned reflex; it may be any stimulus of an organism’s external or internal environment that is perceived by the sensory organs and that causes excitation in the cerebral cortex.

The conditioned stimulus precedes an unconditioned stimulus or coincides with it. Natural conditioned stimuli are used in unconditioned reinforcement; examples are the sight and smell of food. Artificial conditioned stimuli are more varied and do not have a direct relationship to the properties of the unconditioned stimulus; they become positive or negative conditioned signals only when a conditioned reflex is being developed. Conditioned stimuli that are indirect signals of the food-related, defensive, and sexual reflexes are of great importance in the adaptive behavior of animals.

References in periodicals archive ?
Once the respondent relation is established, repeated occurrences of the conditioned stimulus without the unconditioned stimulus weaken the S-R relation until the conditioned stimulus elicits no response.
As mentioned earlier, there was a training session for each pair of participants and a whistle tone as conditioned stimulus.
For Pavlov, learning was stimulus substitution; the conditioned stimulus (CS) substituted for the unconditioned stimulus (UCS).
During the final test, rats were allowed to choose between R1 and R2 in the presence and in the absence of each conditioned stimulus.
Jansen's (1998) cue reactivity theory states that after systematic associations of cues (the conditioned stimulus, CS) with food (the unconditioned stimulus, US), the CS cues will reliably signal food.
Via imaging technique, researchers could see that some neurons were activated by the saccharine, or the conditioned stimulus, and the lithium chloride or the unconditioned stimulus activated others.
A transformation of respondently conditioned stimulus function in accordance with arbitrarily applicable relations.
For example, exposure to glutaraldehyde, a known irritant, is accompanied by an odor that could act as the conditioned stimulus.
Initially designed to account for variations in the effectiveness of reinforcement in conditioning, the model was intended to explain variations in the strength of an associative link between a conditioned stimulus and a reinforcer (pavlovian conditioning) or between an action and its outcome (operant conditioning).
A possible explanation for these results starts out from considering that the DS, in turn, can acquire conditioned stimulus functions (that is, could function as a conditioned reinforcer), increasing the response rate in its presence (Williams & Dunn, 1991).
Experiment 2 demonstrated that similar effects could be found with true statements serving as the conditioned stimulus as well as false statements.
One conditioned taste aversion experiment with rats assessed the impact of extinguishing a target conditioned stimulus (CS), S, in compound with a second CS, A, upon conditioned responding elicited by CS S when presented alone at test.