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.

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]

extinction

/ex·tinc·tion/ (eks-tink´shun) in psychology, the disappearance of a conditioned response as a result of nonreinforcement; also, the process by which the disappearance is accomplished.

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.

extinction

[iksting′shən]
a state of being lost or destroyed.

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.

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]

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.

extinction

the disappearance of a conditioned response as a result of nonreinforcement.
References in periodicals archive ?
As Cizik puts it, "We cannot love our neighbor if we allow the consequences of climate change, pollution, habitat destruction, species extinction, and the spread of human infection diseases to go unabated.
Dr Miranda Stevenson, director of BIAZA, said: "The commended programme demonstrates the huge investment of energy and resources made by our leading zoos to support conservation and help to prevent species extinction in the wild.
It specifically noted problems of water stress, species extinction, declining fish stocks, land degradation, forest loss, urban air pollution in developing countries and increasing greenhouse gas emissions.
Second, they claim that forestry (logging) is the main cause of species extinction when they can't actually name a single species made extinct by forestry.
Conservation biology now recognizes exotic species as second only to habitat destruction in the loss of biodiversity because of their contribution to native species extinction.
In fact, the rates of species extinction cited by Lovejoy and others are consistent with Lomborg's estimate.
The Gordon and Betty Moore Foundation pledged the money to Conservation International (CI) to develop a global initiative to stop species extinction in specific hotspots of biodiversity.
For example, to discredit scientists who study the rate of species extinction, Lomborg offers the following "quote" from researcher Paul Colinvaux, as a way of dismissing estimates such as those published by Norman Myers, E.
Myers is being awarded the prize for being the first to warn of mass species extinction and for continuing to speak out about environmental issues, while May will receive the award for developing mathematical ecology and the fundamental tools for ecological conservation planning, according to the Asahi Glass Foundation, which presents the awards.
In February the Army Corps concluded that opening dams in the spring might avert species extinction, reports Russell.
As the world's population continues to multiply, so, too, will problems such as food shortages, species extinction, and environmental destruction, they say.