Discrimination, in the context of learning, is the ability to distinguish between a conditioned stimulus and other similar stimuli that do not signal the same outcome. It is the opposite of generalisation, in which an organism responds to stimuli similar to the conditioned stimulus.

For example, a dog trained to salivate to a 1000 Hz tone will initially also salivate to a 900 Hz tone (generalisation). With continued training in which only the 1000 Hz tone is paired with food, the dog learns to salivate only to that tone—discrimination. In operant conditioning, discrimination is the ability to respond differently in the presence of different discriminative stimuli.

Key points

• Ability to tell similar stimuli apart
• Opposite of generalisation
• Strengthened by differential reinforcement
• Essential for adaptive behaviour