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Discriminative Stimulus

Techniques > Conditioning > Discriminative Stimulus

Description | Example | Discussion | See also

Description

A discriminative stimulus is one which will reinforce a particular action, increasing the chance that the action will be performed when the stimulus is presented.

A more general description of a discriminative stimulus is of a stimulus that affects the probability of an action happening. This probability can be positive or negative when the action is more or less likely.

An S+ stimulus is one which tells the subject that a reinforcing reward is available. An S- stimulus is one which tells the subject that the reinforcement is not available. The subject will hence learn to approach an S+ and avoid or ignore an S- stimulus.

Example

A dog learns that at lunchtime they may get some food. At the sound of plates clattering, the dog heads for the kitchen.

A teacher claps her hands and waits. The class learns that this means she wants them to be quiet and will wait as long as necessary.

Discussion

One of the basic principles of stimulus and response is for the former to cause the latter. It is hence important in condition to understand the effect that any stimulus may have and is actually having.

A discriminative stimulus may be abbreviated to S^D.

When the the stimulus has a reliable effect, the action is said to be 'under stimulus control'.

A person the subject likes is themselves S+ as their approach makes the subject feel good. A person the subject does not like is S-.

See also

Stimulus