Preference for fixed-interval schedules: effects of unequal initial links

Area of Science:

• Behavioral Psychology
• Animal Cognition
• Operant Conditioning

Background:

• Concurrent schedules of reinforcement are fundamental in understanding choice behavior.
• Previous research indicates biases and undermatching in concurrent schedule performance.
• The interplay between initial and terminal link schedules requires further investigation.

Purpose of the Study:

• To investigate how varying initial- and terminal-link schedules affect preference in homing pigeons.
• To determine if biases and undermatching are independent measures in concurrent schedule performance.

Main Methods:

• Six homing pigeons were trained on concurrent chain schedules.
• Terminal links used fixed-interval schedules (5 sec or 15 sec).
• Initial links varied from VI 27-sec to VI 181-sec, with one constant VI 27-sec.

Main Results:

• Pigeon preference varied as a joint function of initial- and terminal-link schedules.
• When terminal links were unequal, the bias differed compared to equal terminal links.
• The rate of preference change (undermatching) depended on the terminal link assignment of the shorter initial link.

Conclusions:

• Bias in terminal-link schedules is not constant and is influenced by schedule inequality.
• Undermatching is dependent on the specific configuration of initial and terminal links.
• These findings challenge the assumption of independence between bias and undermatching in concurrent schedules.