extinction


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Related to extinction: Mass extinction, Extinction of Species

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 ?
Referred to by scientists as the Lau/Kozlowskii extinction, it was triggered by an all-too-familiar culprit: rapid and widespread depletion of oxygen in the global oceans.
* Extinction Rebellion panelists include journalists Anita McNaught, Nafeez Ahmed and David Wallace-Wells as well as Extinction Rebellion spokespeople Roger Hallam and Rupert Read
Extinction Rebellion also offer training in non-violent direct action through their website for individuals planning on taking part, including showing participants "how to de-escalate tense situation, and what to do if you get arrested".
Although humans have been responsible for the extinction of some species in recent centuries, extinctions have always been an integral part of life.
"The invasion of an alien species is often enough to cause native species to go extinct, whereas we found no evidence for native species being the sole driver of extinction of other natives in any case."
Of those studied, 41 per cent of amphibians are now at risk of extinction, along with by 34 per cent of conifers and 33 per cent of reef corals.
Success varied by BSI approach, with the highest first attempt success rate in the unmodified extinction group (90%), followed by parental presence without support (83%), modified extinction (81%), and parental presence with support (65%).
The cow could be left as the biggest land mammal on Earth in a few centuries, according to a new study that examines the extinction of large mammals as humans spread around the world.
Summary: Size-biased extinction started at least 125,000 years ago in Africa, study says