Behavioral contrast and relative reinforcement frequency in two multiple schedules

Area of Science:

• Behavioral Psychology
• Animal Behavior
• Operant Conditioning

Background:

• Reinforcement schedules are fundamental to understanding operant conditioning.
• Contrast effects, where performance in one schedule is influenced by another, are well-documented.
• The type of reinforcement schedule (e.g., variable-interval vs. fixed-ratio) can impact behavior.

Purpose of the Study:

• To investigate contrast effects in pigeons under multiple reinforcement schedules.
• To compare the susceptibility of low-rate and fixed-ratio schedules to contrast effects.
• To explore potential preferences for time-based versus response-based reinforcement in pigeons.

Main Methods:

• Pigeons were trained on multiple variable-interval (VI) low-rate reinforcement schedules and VI fixed-ratio (FR) reinforcement schedules.
• Contrast effects were assessed by observing changes in performance when schedules were presented together versus alone.
• Performance on individual components of the multiple schedules was compared to baseline performance.

Main Results:

• Contrast effects were observed in the fixed-ratio (FR) reinforcement components.
• Low-rate reinforcement schedules did not exhibit significant contrast effects.
• The reinforcement rate at which no interaction occurred in multiple schedules was higher for FR than for VI schedules.

Conclusions:

• Fixed-ratio reinforcement schedules are susceptible to contrast effects, unlike low-rate schedules.
• Pigeons may exhibit a preference for time-based (variable-interval) reinforcement over response-based (fixed-ratio) reinforcement.
• These findings contribute to understanding the interplay between different reinforcement schedules and animal decision-making.