63: Concepts of Actions and Their Objects

We take concepts to be mental representations involving stored knowledge with some level of generality and modality invariance. Here we explore the neural organization of action concepts. In the neuropsychological literature on action production and comprehension, a mechanical reasoning system diverges from a system based more on object identity, and within the latter system, only rarely is the understanding of tool action selectively impaired relative to concepts of the object involved in an action. The more frequent co- occurrence of action and tool knowledge deficits reflects the close proximity or even extensive overlap of their corresponding neural representations. Neuroimaging work has identified at least two loci important for (primarily concrete) action concepts: in the posterior middle temporal gyrus (pMTG) and the inferior parietal lobe (IPL). Yet both loci seem equally central to aspects of knowledge about tools. Shared neural territory between concrete action concepts and tools seems to reflect more than the fact that tools cue actions. Rather, we argue that it reflects the fact that possibilities for action are inherent attributes of tools and that action concepts inherently specify their typical instruments as part of their predicate structure.