Which principle states that simple explanations should be ruled out experimentally before more complex explanations are considered?

• A. Echoic
• B. Parsimony
• C. Philosophic Doubt
• D. Mand

Answer: (B)

Parsimony is the principle that the simplest account that explains the data should be tested and preferred over more complex ones. In ABA practice, when several accounts could explain a behavior, you start with the simplest hypothesis and design experiments to rule out those minimal accounts before accepting a more elaborate theory. This keeps interpretations tied to observable variables and data, avoiding unnecessary assumptions. Echoic and Mand refer to verbal operants, while Philosophic Doubt describes a general scientific attitude; the idea of preferring simpler accounts is what parsimony embodies.