Discrimination

In a learning theory context, the ability of an animal to respond differently to similar but distinct stimuli.

A horse who responds to “walk on” but not to “halt” is discriminating between cues. A dog who fetches the dumbbell but not the glove on cue is discriminating between objects. A parrot who steps onto one hand but not the other when asked is discriminating between hands. A laboratory rat who responds to a tone of 1000 Hz but not to a tone of 1500 Hz is discriminating between tones.

Discrimination is the complement of generalisation within learning theory. Generalisation extends a learned response across similar stimuli; discrimination narrows the response to specific stimuli. Both are normal learning processes and both are useful in their place.

Discrimination is one of the markers of well-installed training. A behaviour that the animal offers indiscriminately, whether or not the cue is present, is not yet under proper stimulus control. A behaviour that the animal offers only when the specific cue is presented, and not at similar but distinct cues, has been discriminated.

Discrimination training is used widely in applied animal training across species. Sniffer dogs are trained to discriminate between target and non-target scents. Service dogs are trained to discriminate between specific commands among many possible signals. Horses in advanced dressage are trained to discriminate between subtly different leg, seat, and rein cues that correspond to different movements.

The term should not be confused with the social sense of the word as in discrimination against people based on characteristics. In behavioural science, discrimination refers specifically to the ability to respond differently to different stimuli, and carries no moral or social meaning.