Philosophical Assumptions: Selectionism, Determinism, Empiricism, Parsimony, and Pragmatism

Key Takeaways

  • Selectionism explains behavior as the product of consequences across phylogenic, ontogenic, and cultural levels.
  • Determinism assumes behavior is lawful and influenced by variables, even when those variables are not yet known.
  • Empiricism requires objective observation and measurement rather than appeal to opinion or theory alone.
  • Parsimony favors simpler explanations before more complex ones, and pragmatism values useful action tied to outcomes.
Last updated: May 2026

Why Assumptions Matter

Domain A items often test the assumptions behind a decision. The question may not name determinism, empiricism, or parsimony. Instead, it may ask what a BCBA should do when data are limited, a team offers a mentalistic explanation, or an intervention is selected because it sounds convincing.

Core Assumptions

AssumptionExam-Ready MeaningApplied Move
SelectionismBehavior is selected by consequences across evolutionary, learning, and cultural historiesLook for reinforcement histories and current contingencies
DeterminismBehavior is lawful and influenced by variablesKeep assessing instead of calling behavior random
EmpiricismKnowledge comes from observation and measurementUse data before conclusions
ParsimonyRule out simpler explanations firstCheck definitions, measurement, and obvious contingencies
PragmatismTruth is evaluated by practical effectChoose actions that improve prediction and outcomes

Selectionism is central to behavior analysis. Behavior that contacts reinforcement is more likely to occur in similar contexts. Cultural practices can also be selected when they produce consequences for a group.

Determinism does not mean every variable is easy to find. It means the BCBA assumes behavior is not capricious or caused by inner traits that end the analysis. The correct answer keeps searching for functional variables.

Empiricism separates behavior analysis from explanation by authority. A supervisor, parent, or teacher may have useful observations, but the BCBA still needs direct or defensible data to support decisions.

Parsimony is a common exam trap. If a learner stops responding, first consider simple behavior-analytic possibilities such as unclear instructions, weak reinforcement, satiation, extinction, or measurement error before complex explanations.

Pragmatism does not mean doing whatever is easiest. In behavior analysis, practical value is judged by whether the approach helps prediction, influence, and socially meaningful improvement while staying conceptually and ethically sound.

Fast Sorting Rule

When an answer says behavior is unknowable, choose against it. When an answer says measure, test, replicate, or examine contingencies, it is usually closer to Domain A.

Test Your Knowledge

A learner's requests increased after requests consistently produced access to preferred items. Which assumption is most directly illustrated?

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B
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D
Test Your Knowledge

Staff say a client's self-injury is random because it occurs in several rooms and with several people. What response best reflects determinism?

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B
C
D
Test Your Knowledge

A team proposes a complex sensory explanation before checking whether task difficulty changed. Which assumption should guide the BCBA first?

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B
C
D