Psychological Science 21(9) 1215–1219 © The Author(s) 2010 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0956797610378307 http://pss.sagepub.com Increasing evidence suggests that merely seeing objects that are typically manipulated in certain ways automatically trig- gers motor simulations for using them. For example, people are faster to make orientation judgments about a picture of a tool when the tool’s handle is oriented toward the hand that will make a response than when it is oriented away from the responding hand. This finding suggests that the orientation of a tool evokes an action program for grasping it with the closest hand (Tucker & Ellis, 1998). Similarly, when reaching for a pencil, people have a larger grip aperture if a hammer is also present than if the pencil is by itself, which suggests that action programs for grasping different objects in peripersonal space are covertly triggered in parallel and interfere with each other (Castiello, 2005). Furthermore, neuroimaging studies indicate that cortical networks for hand action are engaged more by the sight of tools than by the sight of animals (see Lewis, 2006). However, the extent to which motor simulations contribute functionally to tool recognition (as proposed by accounts of embodied cognition) remains unclear. Three possibilities exist: First, motor simulations may be necessary for tool rec- ognition. Second, motor simulations may be supportive but not necessary for tool recognition. And finally, motor simula- tions may be connected to, but not functionally relevant for, tool recognition. Recent findings that bear on this issue come from neuropsychological studies of patients with apraxia, an impairment of tool use that cannot be attributed to either low- level disturbances of motor control or high-level problems with task comprehension. Whereas some apraxic patients are impaired in both tool use and tool recognition, many are impaired in just tool use and have intact tool recognition. This suggests that motor simulations are not necessary for the latter task (Negri et al., 2007). Nevertheless, motor simulation may still have a functional role in tool recognition. Motor interference impairs learning how to use functional objects (Paulus, Lindemann, & Bekker- ing, in press). Furthermore, motor simulation appears to play a causal role in several other types of cognitive processing, most notably in language comprehension. Facilitation of motor regions for the arms and legs (via transcranial magnetic stimu- lation) decreased participants’ time to make judgments of action words related to the specific body part that was stimu- lated (Pulvermüller, Hauk, Nikulin, & Ilmoniemi, 2005; but see Buccino et al., 2005, for another causal, though inhibitory, Corresponding Author: Jessica K. Witt, Purdue University, Department of Psychological Sciences, 703 Third St., West Lafayette, IN 47907 E-mail: jkwitt@purdue.edu A Functional Role for Motor Simulation in Identifying Tools Jessica K. Witt 1 , David Kemmerer 1,2 , Sally A. Linkenauger 3 , and Jody Culham 4 1 Department of Psychological Sciences, Purdue University; 2 Department of Speech, Language, and Hearing Sciences, Purdue University; 3 Department of Psychology, University of Virginia; and 4 Department of Psychology, University of Western Ontario Abstract Embodied cognition promotes the involvement of the motor system in cognitive processing, such as tool identification. Although neuropsychological studies suggest that the motor system is not necessary for identifying tools, it may still have a functional role in tool recognition. To test this possibility, we used a motor interference task: Participants squeezed a rubber ball in one hand while naming pictures of tools and animals. Participants were faster and more accurate in naming the tools that were oriented with the handle facing away from the squeezing hand than in naming the tools that were oriented with the handle facing toward the squeezing hand. There was no effect of orientation for animals. Given that participants simulate grasping a tool with the hand closest to the handle, this result demonstrates that interfering with the ability to simulate grasping impairs tool naming and suggests that motor simulation has a functional role in tool identification. Keywords tool use, object identification, motor simulation, motor interference, embodied cognition Received 2/24/09; Revision accepted 2/1/10 Research Report