Behaviour Modification – Lecture 7
Chapter 7 – Stimulus Control: Discrimination and Generalization
➢ How do we learn to perform certain behaviours at certain times but not others?
➢ Critical Questions
What is an antecedent stimulus and how is it involved in stimulus control of operant
How is stimulus control developed through stimulus discrimination training?
What is the three-term contingency?
What is generalization and how does it differ from discimination?
Behaviour is reinforced in specific circumstances (when specific antecedents are present)
Outcome: Behaviour is more likely to occur in the future in similar circumstances
Behaviour is no longer reinforced when it occurs in specific circumstances (when specific
antecedents are present)
Outcome: Behaviour stops occuring in the future in similar circumstances
Behaviour is punished in specific circumstances (when specific antecedents are present)
Outcome: Behaviour stops occurring in the future in similar circumstances.
➢ 3-Term Contingency (A-B-C's of Operant Behaviour)
Contingency of reinforcement
What is a contingency of reinforcement?
• The reinforcement follows the behaviour and not the other way around.
• The consequences of a given behaviour are controlled by the antecedents or specific
circumstances in the environment. We're focusing only on the antecedents. The
functional relationship among the different components.
• A→ B → C
• Ex: Phone rings → Pick it up → Talk to someone
Phone doesn't ring → Pick it up → No one there
Outcome: You are more likely to pick up the phone when it rings but not when it
is not ringing.
With frends → tell stories → friends laugh
With parents → tell stories → no laughs – maybe reprimands
Outcomes: You are more likely to tell stories to friends but not to parets.
• Overall what's taking place is stimulus discrimination training
➢ Stimulus Discrimination Training:
Reinforce the target behaviour in the presence of 1 specific antecedent
Notation: Sᴅ Sᴅ = discriminative stimulus
The SD is the antecedent stimulus that is present when the behaviour is reinforced
Sᴅ = ringing telephone
Do not reinforce the behaviour in the presence of other antecedents
S∆ = S-delta
other antecedent stimuli that are not followed by a reinforcing/punishing consequence
These are called S-deltas
S∆ is the antecedent stimulus that is present when the behaviour is not reinforced
Sᴅ → Behaviour → Reinforcer (SR)
S∆ → Behaviour → Extinction (EXT)
Outcome: In the future, the behaviour is more likely to occur when the Sᴅ is present but
not when the S∆ is present.
As with other basic principles of behaviour modification, the components of stimulus
discrimination training were clearly delineated in the laboratory.
Pigeons and rats were used.
Basic communication skills are developed through Discrimination Training
• With trial and error we begin to learn
• Ex:Ask kid to spell the word dog. Only reinforce him when he spells dog when the
picture of a dog is shown but