Plasticity, stereotypy, intra-individual variability and personality: handle with care

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Animal behavior

Background:

• Recent focus on within-individual variability in evolutionary thinking.
• Proliferation of terms like behavioral plasticity, stereotypy, imprecision, and intra-individual variability (IIV) causing confusion.
• Need for conceptual clarity in understanding behavioral variability origins.

Purpose of the Study:

• Critically review concepts of behavioral variability within individuals.
• Clarify the relationship between within-individual variability and between-individual differences (personality).
• Address conceptual overlaps and potential confusion in the literature.

Main Methods:

• Literature review and conceptual analysis.
• Critical overview of existing terminology and theoretical frameworks.
• Distinction between individual-level and population-level phenomena.

Main Results:

• Behavioral plasticity and IIV do not overlap, but both overlap with stereotypy.
• Stereotyped behavior faces challenges regarding abnormality and function.
• Personality is logically independent of activational plasticity and IIV, emerging at the population level.

Conclusions:

• Acknowledging internal variability and between-individual differences is vital for personality studies.
• Failure to distinguish these phenomena hinders unified accounts from heterogeneous data.
• Clear conceptual frameworks are needed for robust evolutionary and personality research.