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 ?
1996: Using statistical probability to increase confidence of inferring species extinction.
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.
The 300 scientists at the September 2006 California Climate Change Research Conference reported that the impacts of global warming on California include: more heat waves like last July's, increased forest fires, increased smog, decreased crop productivity, species extinction, decreased water supply, increasing insect-caused disease and coastal flooding and erosion caused by sea-level rise.
Twycross established a new programme of tertiary education sessions, which demonstrate how modern zoos can be a powerful force for conservation, tackling issues such as species extinction in the wild.
We continue to have a major role to play in tackling many environmental problems, such as climate change, poverty, pollution, species extinction, the conservation of wetlands and their wildlife.
A handful of black-and-white drawings illustrate this high adventure with underlying themes about the importance of cooperation and teamwork, as well as caution against environmental habitat destruction and species extinction.
Other human-related issues that deserve public health attention, Last said, are escalating species extinction, collapsing ocean fisheries, increasing conflicts and changing global climates.
However, the current rate of species extinction is unprecedented.
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.
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.