The spatio-temporal architecture of everyday manual behavior

Abstract

In everyday activities, humans use a finite number of postural hand configurations, but how do they flow into each other to create sophisticated manual behavior? We hypothesized that hand movement emerges through the temporal dynamics of a set of recurrent hand shapes characterized by specific transitions. Through a sensorized glove, we collected kinematics data from thirty-six participants preparing and having breakfast in naturalistic conditions. By means of a combined PCA/clustering- based approach, we identified a repertoire of hand states and their transitions over time. We found that manual behavior can be described in space through a complex organization of basic configurations. These, even in an unconstrained experiment, recurred across subjects. A specific temporal structure, highly consistent within the sample, seems to integrate such identified hand shapes to realize skilled movements. Our findings suggest that the simplification of the motor commands unravels in the temporal dimension more than in the spatial one.