Sample-stimulus discriminability and sensitivity to reinforcement in delayed matching to sample

Area of Science:

• Cognitive Psychology
• Animal Behavior
• Behavioral Neuroscience

Background:

• Delayed matching-to-sample tasks are crucial for understanding memory and choice.
• Investigating how retention intervals impact stimulus control is essential for behavioral models.

Purpose of the Study:

• To examine the relationship between retention interval, sample stimulus discriminability, and differential reinforcement in pigeons.
• To determine if increasing delay is functionally similar to increasing stimulus similarity.

Main Methods:

• Pigeons were trained on a delayed matching-to-sample task using red and green stimuli.
• Retention intervals (0.01–12 s) and reinforcement probabilities were manipulated.
• Sample-stimulus discriminability and response bias were measured.

Main Results:

• An interaction was found between sample discriminability and differential reinforcement control.
• At longer retention intervals, sample discriminability decreased.
• Choice behavior sensitivity to reinforcer ratio changes increased with longer delays.

Conclusions:

• Increasing retention interval in delayed matching-to-sample tasks functionally resembles increasing physical stimulus similarity.
• Findings suggest that memory decay and stimulus similarity share common control mechanisms in choice behavior.