Can Sol's Explanation for the Evolution of Animal Innovation Account for   Human Innovation?
  Sol argues that innovation propensity is not a specialized adaptation resulting from targeted selection but an instance of exaptation because selection cannot act on situations that are only encountered once. In exaptation, a trait that originally evolved to solve one problem is co-opted to solve a new problem; thus the trait or traits in question must be necessary and sufficient to solve the new problem. Sol claims that traits such as persistence and neophilia, are necessary and sufficient for animal innovation, which is a matter of trial and error. We suggest that this explanation does not extend to human innovation, which involves strategy, logic, intuition, and insight, and requires traits that evolved, not as a byproduct of some other function, but for the purpose of coming up with adaptive responses to environmental variability itself. We point to an agent based model that indicates the feasibility of two such proposed traits: (1) chaining, the ability to construct complex thoughts from simple ones, and (2) contextual focus, the ability to shift between convergent and divergent modes of thought. We agree that there is a sense in which innovation is exaptation--it occurs when an existing object or behaviour is adapted to new needs or tastes--and refer to a mathematical model of biological and cultural exaltation. We conclude that much is gained by comparing and contrasting animal and human innovation. 
Liane Gabora and Apara Ranjan
q-bio.NC q-bio.PE