Stimulus control of responding during a fixed-interval reinforcement schedule

Area of Science:

• Behavioral neuroscience
• Animal behavior

Background:

• Fixed-interval schedules are fundamental in operant conditioning.
• Stimulus control describes how environmental cues influence behavior.

Purpose of the Study:

• To investigate dimensional stimulus control in pigeons.
• To determine how reinforcement history affects stimulus control under fixed-interval schedules.

Main Methods:

• Pigeons were trained on a fixed-interval schedule with a vertical line stimulus.
• Test sessions involved varying the line's orientation to assess stimulus control.
• Response gradients were analyzed during different phases of the interval.

Main Results:

• Excitatory gradients (increased responding) were observed with the vertical line in the terminal interval phase.
• Inhibitory gradients (decreased responding) were seen in the early interval phase, contingent on reinforcement history.
• Conditional stimulus control was demonstrated, varying with reinforcement association.

Conclusions:

• The stimulus present during a fixed-interval schedule exerts conditional dimensional control.
• Reinforcement-associated stimuli modulate whether the interval stimulus elicits excitatory or inhibitory control.