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 ?
If true passenger pigeons, mammoths and countless other extinct animals remain, despite our best efforts, lost from nature's family tree forever, then what are the logical motivations behind continuing this field of research?
So you brought back a bunch of extinct animals from the dead - now what?
When asked about the possibility of obtaining DNA of extinct animals like the woolly mammoth in order to clone it, Carroll said, "Yes, I think we'll be able to get much, if not all, of the woolly mammoth DNA.
The discovery in 1927, in Folsom, New Mexico, of a projectile among the rib bones of an ancient animal revealed the coexistence of man with now extinct animals during the Ice Age.
Caption: Rachel Schwartz-Narbonne studies the diet of woolly mammoths by analyzing collagen preserved on the frozen bones of these extinct animals.
The icy vials may someday even be used in experiments to resurrect recently extinct animals, like the Hawaiian Po'ouli bird.
bridgei, "we can reconstruct what colors extinct animals example, dinosaurs could see," Tanaka added.
Will extinct animals be able to survive in a changed environment?
Building bots based on living and extinct animals could also help to study fish evolution (SN: 6/2/12, p.
If it were not for their money, there would be many more extinct animals both here and in other countries and continents.
In addition to establishment of national parks, he said safari parks would be established at districts' level where species of different extinct animals would also be introduced and kept to create awareness among students and masses about role of wildlife in our daily lives.
Sir David, who will look at extinct animals in a new show on Sky, also highlighted the plight of garden birds.