1. the ability to distinguish between stimuli or objects that differ quantitatively or qualitatively from one another.

2. the ability to respond in different ways in the presence of different stimuli. In conditioning, this is usually established in experiments by differential reinforcement or differential conditioning techniques. See discrimination learning; discrimination training.

3. differential treatment of the members of different ethnic, religious, national, or other groups. Discrimination is usually the behavioral manifestation of prejudice and therefore involves negative, hostile, and injurious treatment of the members of rejected groups. By contrast, reverse discrimination is the favorable treatment of the oppressed group rather than the typically favored group. See also racial discrimination; sex discrimination; social discrimination. —discriminate vb.