What is the role of motor simulation in action and object recognition? Evidence from apraxia

Abstract

An important issue in contemporary cognitive neuroscience concerns the role of motor production processes in perceptual and conceptual analysis. To address this issue, we studied the performance of a large group of unilateral stroke patients across a range of tasks using the same set of common manipulable objects. All patients (n = 37) were tested for their ability to demonstrate the use of the objects, recognize the objects, recognize the corresponding object-associated pantomimes, and imitate those same pantomimes. At the group level we observed reliable correlations between object use and pantomime recognition, object use and object recognition, and pantomime imitation and pantomime recognition. At the single-case level, we document that the ability to recognize actions and objects dissociates from the ability to use those same objects. These data are problematic for the hypothesis that motor processes are constitutively involved in the recognition of actions and objects and frame new questions about the inferences that are merited by recent findings in cognitive neuroscience.

Keywords:

• Apraxia
• Embodied cognition
• Action recognition
• Object recognition.

Acknowledgments

The authors are grateful to the patients and control participants, as well as to their families, for their willing participation throughout many hours of testing. The authors thank Alina Menichelli and Anna Sverzut for their help in testing patients and Eduardo Navarrete for his comments on an earlier version of this manuscript. Preparation of this manuscript was supported in part by an NSF Graduate Research Fellowship to B.Z.M., NIH Grant DC04542 to A.C., and by a PRIN grant to R.I.R.

Notes

¹This line of reasoning does not follow necessarily. It depends on how modular the cognitive systems involved in these various capacities are assumed to be. The above reasoning goes through only on a very general construal of the interdependence between putatively “higher order” social reasoning and “more basic” action recognition.

² It is unlikely that P.I.'s impairment for recognizing the pantomimes can be explained by a general visual impairment, because the patient was within the normal range on the Visual Object and Space Perception Battery (VOSP) and object decision screening tests, ruling out at least some types of a general visual impairment (see Appendices A and C).