Science / Psychiatry / Extinction: The weakening of a reinforced operant response as a result of ceasing reinforcement. See also operant conditioning. Also, the elimination of a conditioned response by repeated presentations of a conditioned stimulus without the unconditioned stimulus. See also respondent conditioning.
Science / Biology / Mass Extinction: A time during which extinction rates are generally accelerated so that more than 50% of all species then living become extinct; results in a marked decrease in the diversity of organisms. Mass extinct MORE
Science / Biology / Ordovician Extinction: Paleozoic-aged mass extinction possibly related to glaciation in the southern-hemisphere supercontinent Gondwana. MORE
Science / Biology / Secondary Extinction: The death of one population due to the extinction of another, often a food species. MORE
Science / Geology / Extinction Angle: The angle between a crystallographic direction, such as a face or cleavage plane, and the direction in which all light is blocked by a pair of crossed polarizers. MORE
Science / Psychiatry / Sensory Extinction: Failure to report sensory stimuli from one region if another region is stimulated simultaneously, even though when the region in question is stimulated by itself, the stimulus is correctly reported. MORE