title: Lateral interception II: predicting hand movements.
abstract: D. M. Jacobs and C. F. Michaels (2006) concluded that aspects of hand movements in lateral catching were predicted by the ratio of lateral optical velocity to expansion velocity. Their conclusions were based partly on a modified version of the required velocity model of catching (C. E. Peper, R. J. Bootsma, D. R. Mestre, & F. C. Bakker, 1994). The present article considers this optical ratio in detail and asks whether it, together with a control law, predicts the (often curious) hand trajectories observed in lateral interception. The optical ratio was used to create a succession of target-position inputs for the vector integration to endpoint model of hand movements (D. Bullock & S. Grossberg, 1988). The model used this succession, initial hand position, and model parameters (fit to 60 trials) to predict hand trajectories on each trial. Predicted trajectories were then compared with observed hand trajectories. Hand movements were predicted accurately, especially in the binocular condition, and were superior to predictions based on lateral ball position, the input variable of the required velocity model. The authors concluded, as did C. E. Peper et al. (1994), that perceivers continuously couple movements to optics.
authors.affiliation: Center for the Ecological Study of Perception and Action, Department of Psychology, University of Connecticut, Storrs, CT 06269, USA. claire.michaels@uconn.edu
authors.forename: Claire F
authors.initials: CF
authors.lastname: Michaels
authors.forename: David M
authors.initials: DM
authors.lastname: Jacobs
authors.forename: Raoul M
authors.initials: RM
authors.lastname: Bongers
mesh_terms: D001288:Attention; D004193:Discrimination Learning / Q000502:physiology*; D004215:Distance Perception / Q000502:physiology; D030141:Feedback, Psychological; D006225:Hand / Q000502:physiology*; D006801:Humans; D007600:Judgment; D008960:Models, Psychological; D009039:Motion Perception / Q000502:physiology; D009048:Motor Skills / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D011214:Practice, Psychological; D011340:Problem Solving