Learned persistence at 11-12 days but not at 10-11 days in infant rats

Area of Science:

• Developmental Psychology
• Behavioral Neuroscience
• Animal Learning

Background:

• Persistence is a key behavioral trait influenced by early life experiences.
• Partial reinforcement schedules are known to enhance response persistence during extinction.
• Understanding the developmental trajectory of learning is crucial for behavioral science.

Purpose of the Study:

• To determine the transitional age in rat pups for acquiring persistence through appetitive partial reinforcement.
• To investigate the emergence of the partial reinforcement extinction effect (PREE) in early development.

Main Methods:

• Two experiments utilized milk-suckling from an anesthetized dam as a positive reinforcer.
• Rat pups of different age groups (10-11 days and 12-13 days) were trained under partial reinforcement conditions.
• Subsequent extinction trials were conducted to assess response persistence and the PREE.

Main Results:

• Rat pups aged 12-13 days exhibited the partial reinforcement extinction effect (PREE) in Experiment I.
• Pups trained at 11-12 days of age and tested at 13 days showed a PREE in Experiment II.
• Pups aged 10-11 days did not demonstrate the PREE in either experiment, regardless of training or testing age.

Conclusions:

• The critical developmental window for learning persistence via partial reinforcement in rat pups is between 11 and 12 days of age.
• The partial reinforcement extinction effect (PREE) emerges in rat pups around this transitional age.
• These findings highlight a specific period of cognitive development influencing learning and behavioral persistence.