Organizing Concepts

Whereas Chapters 3–5 deal with different aspects of the representation of word meanings, Chapter 6 focuses on their organization. The two most well-studied domains of object concepts are animals and tools, and words for them (e.g., dog and scissors) appear to be organized as separate, category-specific circuits, each of which includes all three types of representation mentioned above – namely, sensory/motor representations in modal networks, integrated representations in the GSN/DMN, and purely verbal representations in the core language network. The contrasting specializations of these circuits for animal and tool concepts reflect many factors that involve both the learning environment and innate patterns of cortical connectivity. This chapter also shows that three other categories of lexically encoded object concepts similarly appear to have distinct neural substrates: plants (especially fruits and vegetables like apple and potato); people (including face parts like eye, body parts like hand, and unique individuals like Tom Hanks); and places (including generic scenes like beach and famous landmarks like the Eiffel Tower). What’s more, there are some hints that hundreds of other classes of word meanings may be distinguished, like in a thesaurus, by the fine-grained representational geometries of numerous cortical areas, especially those comprising the GSN/DMN.