Discriminative stimulus control and the effects of concurrent operants

Area of Science:

• Behavioral science
• Animal behavior
• Operant conditioning

Background:

• Discriminative stimulus control is fundamental to understanding how environmental stimuli guide behavior.
• Concurrent operant contexts allow for the simultaneous investigation of multiple behavioral choices and their controlling stimuli.

Purpose of the Study:

• To investigate the discriminative-stimulus-control functions under concurrent operant schedules in pigeons.
• To determine how varying reinforcement frequencies on concurrent schedules influence stimulus control gradients.
• To assess the impact of changeover delay on stimulus control within concurrent operant settings.

Main Methods:

• Pigeons were trained on concurrent variable-interval schedules with differential reinforcement frequencies on two response keys.
• One key featured a vertical line on a green background; the other featured green alone.
• Stimulus control gradients were measured by systematically varying line orientation, and changeover delay effects were analyzed.

Main Results:

• Steeper stimulus control gradients were observed when reinforcement frequencies were equal between keys.
• Flatter gradients occurred when the alternative key had twice the reinforcement frequency.
• Changeover delay had minor effects on stimulus control, unlike its significant impact on steady-state responding.

Conclusions:

• Reinforcement frequency is a critical determinant of stimulus control strength in concurrent operant situations.
• The relationship between reinforcement schedules and stimulus control is complex and influenced by relative reinforcement rates.
• Changeover delay's limited effect on stimulus control suggests its primary role is in shaping response allocation rather than stimulus discrimination.