Defining the stimulus--a memoir.

Area of Science:

• Psychology
• Animal Cognition
• Learning Theory

Background:

• The definition of a stimulus is central to understanding behavior.
• Traditional learning theory focused on direct stimulus-response (S-R) connections.
• The limitations of S-R models necessitated new theoretical frameworks.

Purpose of the Study:

• To explore the expansion of the stimulus definition in animal learning.
• To investigate the role of internal representations in animal cognition.
• To demonstrate how representations enhance explanatory power beyond traditional models.

Main Methods:

• Reviewing historical and theoretical shifts in learning and cognition.
• Analyzing examples like delayed matching-to-sample, concept formation, and spatial memory.
• Operationally defining internal representations for scientific inquiry.

Main Results:

• The concept of internal representations bridges the gap between stimulus and response.
• Representations account for behaviors where the stimulus is absent.
• Expanded stimulus definitions incorporating representations significantly improve performance prediction.

Conclusions:

• Animal cognition research necessitates the inclusion of internal representations.
• Operationalizing representations allows for rigorous scientific investigation.
• An expanded stimulus concept provides a more comprehensive model of animal behavior.