Evolutionary explanation
Evaluate a specific historical explanation rather than accepting a plausible story as a test.
The question
What evidence distinguishes an evolved adaptation from a byproduct or a learned response?
Evolutionary explanations of behavior inherited a distinction between traits shaped for a function and features arising as consequences of other traits. Buss and colleagues (1998) set out competing evolutionary categories.
What the claims mean
Adaptation hypothesis
A proposed psychological mechanism is explained by selection for a particular function. It needs evidence of design and predictions that distinguish alternatives.
Byproduct or exaptation
A feature may arise from another adaptation or acquire a use different from the one that shaped its origin.
Learning and development
An evolutionary explanation still needs a developmental account. Learning can be part of an evolved system rather than an alternative to evolution.
Evidence to examine
Buss and colleagues (1998) discuss adaptations, exaptations and spandrels as distinct explanatory possibilities. Their paper is a theoretical analysis, not a direct experimental confirmation of every proposed adaptation.
Shared ground and disagreement
What the accounts can share
Evolution is relevant to human biology. That general fact does not validate any particular proposed explanation of a behavior.
What remains at issue
Which historical selection pressures and functional mechanisms account for a specific feature, and whether a rival explanation predicts the observations equally well.
Limits and next tests
A behavior being common, useful now or different between groups does not by itself establish its evolutionary origin. Historical explanations face limited direct access to ancestral conditions.
What would help distinguish the claims?
Specify rival predictions using comparative, developmental and cross-population evidence. Ask what result would count against the adaptation claim before collecting confirmatory examples.
Textbook connection
ContextualOpenStax Psychology 2e: 3.1 Human Genetics
The section provides background vocabulary. It does not cover the full debate or establish the status of later research.
Sources and access
- Buss, D. M., Haselton, M. G., Shackelford, T. K., Bleske, A. L., & Wakefield, J. C. (1998). Adaptations, exaptations, and spandrels. The American Psychologist, 53(5), 533–548. https://doi.org/10.1037//0003-066x.53.5.533Consulted sourceAbstract inspected
Primary bibliographic record and complete abstract retrieved from Europe PMC on October 21, 2026. Full paper methods and supplements were not inspected.