Undermatching and overmatching: The fixed-ratio changeover requirement

Area of Science:

• Behavioral psychology
• Animal behavior studies
• Operant conditioning

Background:

• Matching law in behavioral economics predicts response distribution based on reinforcement schedules.
• Previous research indicated overmatching with higher changeover requirements (5-10 responses).

Purpose of the Study:

• To investigate the effect of lower fixed-ratio changeover requirements (1, 2, 4 responses) on concurrent schedules.
• To determine if undermatching or overmatching can be systematically produced by varying changeover requirements.

Main Methods:

• Concurrent variable-interval schedules (2-min and 6-min) were used.
• The fixed-ratio changeover requirement was manipulated (1, 2, or 4 responses).
• Response and time allocation data were analyzed.

Main Results:

• A 4-response requirement led to overmatching in both response and time data.
• A 1-response requirement resulted in undermatching in time data, with mixed response data.
• A 2-response requirement showed undermatching in time data and overmatching in response data.

Conclusions:

• Matching is not a fixed outcome; it is sensitive to changeover requirements.
• Systematic variation of changeover requirements can produce either undermatching or overmatching.
• Findings extend previous research and suggest a continuum of matching behavior based on response requirements.