Maintenance of responding by squirrel monkeys under a concurrent shock-postponement, fixed-interval...

Area of Science:

• Behavioral psychology
• Animal behavior studies
• Operant conditioning

Background:

• Operant conditioning principles explain how consequences shape behavior.
• Shock-postponement (avoidance) and shock-presentation schedules are used to study learned responses.
• Squirrel monkeys serve as a model organism in behavioral research.

Purpose of the Study:

• To investigate the development and maintenance of behavior under shock-based schedules.
• To determine if prior avoidance training influences subsequent response to shock-presentation.
• To examine the differential control of behavior by simultaneous shock-presentation and postponement.

Main Methods:

• Two squirrel monkeys were trained on a chain-pulling response under a shock-postponement schedule.
• Lever-pressing responses were introduced with no consequence, then under a concurrent fixed-interval shock-presentation schedule.
• Subsequent phases involved shock-presentation alone, followed by simultaneous shock-postponement and shock-presentation schedules.

Main Results:

• Chain-pulling behavior was maintained by shock-postponement.
• Lever-pressing behavior developed and was maintained by the fixed-interval shock-presentation schedule.
• Simultaneous schedules resulted in differential responding: steady chain-pulling and accelerating lever-pressing.
• Response rates correlated directly with shock intensity.

Conclusions:

• A history of shock-avoidance training facilitates the development of responses maintained by shock-presentation.
• Differential behavioral patterns can be simultaneously maintained by both shock-presentation and shock-postponement schedules.
• Electric shock intensity is a critical factor in controlling response rates under both schedule types.