A delay-specific differential outcomes effect in delayed matching to sample

Area of Science:

• Cognitive Psychology
• Animal Behavior
• Learning and Memory

Background:

• Delay-specific remembering shows enhanced accuracy at certain retention intervals.
• The differential outcomes effect (DOE) improves accuracy across all delays with varied rewards.
• Existing DOE theories link effects to reward expectancies influencing stimulus control.

Purpose of the Study:

• To investigate a delay-specific differential outcomes effect (DOE).
• To test if differential outcomes at specific delays, and same outcomes at others, enhance accuracy selectively.
• To examine implications for theories attributing DOE to reward expectancies.

Main Methods:

• Four pigeons performed delayed matching-to-sample tasks with mixed within-session delays (e.g., 0.5, 5, 15 s).
• Differential reward durations (differential outcomes) were provided for correct choices at some delays.
• Same reward durations (same outcomes) were provided at other delays within the same session.

Main Results:

• Evidence of a delay-specific DOE was observed, with improved accuracy at delays featuring differential outcomes.
• Accuracy was higher when differential outcomes were used compared to when same outcomes were used.
• A standard DOE was confirmed in a separate experiment comparing all-same vs. all-differential outcomes.

Conclusions:

• The findings support the existence of a delay-specific differential outcomes effect.
• Results suggest that reward expectancies may exert influence selectively at specific delays.
• This provides valuable insights into the mechanisms underlying memory and decision-making under delayed reward conditions.