Multi-use and constraints from original use

Anderson's theory is plausible and largely consistent with the data. However, it remains underspecified on several fronts, and we highlight areas for potential improvement. Reuse is described as duplicating a functional component, preserving one function and tinkering to add another function. This is a promising model, but Anderson neglects other reasonable alternatives and we highlight several. Evidence cited in support of reuse fails to uniquely support it among a broader set of multi-use theories. We suggest that a more stringent criterion for direct support of reuse may be satisfied by focusing on previous adaptive functions (original use).