Evolution of general intelligence: The role of working memory, metaphor, and analogical reasoning in solving novel problems

  Evolutionary psychologists have proposed that the mind is a collection of modules – domain-specific and encapsulated mechanisms that map characteristic inputs onto characteristic outputs.  These mechanisms present optimal solutions to recurrent problems with a restricted problem space. However, modules are incapable of solving novel problems, or generating novel solutions to longstanding problems – things that humans, and many other animals (e.g., ravens), are capable of doing. To explain how we deal adaptively with novelty we need to postulate mechanisms of general intelligence (g). Mechanisms underlying g include the executive functions of working memory able to activate goal-relevant representations while at the same time inhibiting potentially distracting representations. These mechanisms are critical for constructing, executing and maintaining a plan of action. They are domain-general; measures of working memory capacity predict performance across a wide range of tasks (provided they are novel and demanding of attentional resources). They are also unencapsulated: Representations activated in problem solving come from a wide range of domains. Paradigmatic examples of this are metaphor and analogical reasoning – capacities known to correlate highly with g. Metaphor and analogy involve activating representations associated with a source domain (e.g., “weeds”) and mapping those features onto a target domain (e.g., “rumors”). Properties irrelevant to the mapping are inhibited.  The features involved tend to be higher-order, abstract features associated with concepts.  The abstract nature of metaphor and analogy allows for conceptual mappings to occur across semantically very different domains. There seems to be no limit to the domains that humans can bring together to create such representations, including ones useful for solving novel problems. This is inconsistent with the assumption that the mind is made up of solely modular mechanisms.