extinction

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extinction

 [eks-ting´shun]
in psychology, the disappearance of a conditioned response as a result of its not being reinforced; also, the process by which the disappearance is accomplished. See also conditioning.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ex·tinc·tion

(eks-tingk'shŭn),
1. In behavior modification or in classical or operant conditioning, a progressive decrease in the frequency of a response that is not positively reinforced; the withdrawal of reinforcers known to maintain an undesirable behavior.
2. Synonym(s): absorbance
[L. extinguo, to quench]
Farlex Partner Medical Dictionary © Farlex 2012

extinction

(ĭk-stĭngk′shən)
n.
1.
a. The act of extinguishing: The extinction of the fire took several hours.
b. The condition of being extinguished: mourned the extinction of her dreams.
2. The fact of being extinct or the process of becoming extinct: the extinction of the passenger pigeon; languages that are in danger of extinction.
3. Psychology A reduction or a loss in the strength or rate of a conditioned response when the unconditioned stimulus or reinforcement is withheld.
4. Physiology A gradual decrease in the excitability of a nerve to a previously adequate stimulus, usually resulting in total loss of excitability.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

extinction

Psychiatry A facet of operant–classical conditioning, in which the conditioned response is weakened and eventually disappears by nonreinforcement. See Operant conditioning, Respondent conditioning, Sensory extinction.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

ex·tinc·tion

(eks-tingk'shŭn)
1. In behavior modification or classical or operant conditioning, a progressive decrease in the frequency of a response that is not positively reinforced.
See: conditioning
2. Synonym(s): absorbance.
[L. extinguo, to quench]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

extinction

  1. the act of making EXTINCT or the state of being extinct.
  2. the elimination of an allele of a gene in a population, due to RANDOM GENETIC DRIFT or to adverse SELECTION pressures.
  3. any periodical, catastrophic event resulting in a species or larger taxonomic group dying out abruptly at a particular point in geological history. Such extinctions are thought to be cyclical, occurring every 28.4 million years, and have been attributed to cosmic activity such as showers of large asteroids or comets, though neither the periodicity nor its causes are at present universally accepted.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
"After 2 years of observing parasitism above 90 percent, and extremely poor productivity, we calculated statistically that the bird would become locally extinct within 10 years without immediate intervention."
He was able to reintroduce locally extinct plant species which had resisted dramatic changes and escaped camel overgrazing.
Biologists have even tranplanted CBS monkeys to Cockscomb Basin, a jaguar preserve at the base of the Maya Mountains, to begin a new population where howlers have been locally extinct for years.
For their 12 Seder, after the question, "Why is this night different?" was asked and answered, Rea and Ijichi had participants mention the locally extinct species by name: the California condor, the yellow-billed cuckoo, Swainson's hawk, the bank swallow, the black rail, the Fulvous tree duck, as well as the pronghorn (the American antelope), the long-earned kit fox, and the Southern California grizzly.
Lapwing fared even worse, and could be said to be locally extinct.
The speckled wood was noted as being widespread in the 1840s but was locally extinct by the end of the century.
In the present study, the researchers found that although no species that were present in 1997 had gone locally extinct, many were now so rare as to play little role in the community.
Indeed, some populations may already have become locally extinct as a result of drought and competition from invasive exotic species as well as longer term climate change.
Those species that are listed as being endangered, threatened, extirpated (locally extinct) or of special concern are subject to SARA.
This species is considered to be locally extinct in Germany and Austria for example, whereas it still occurs in Italy and Spain.
We thought they were locally extinct, but earlier this year I spotted a new pair.

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