title: Fitts' Theorem in Oculomotor Control: Dissociable Movement Times for Amplitude and Width Manipulations.
abstract: The authors examined whether movement times (MT) for discrete saccades are constant given equivalent index of difficulty (ID) values (i.e., unitary nature of Fitts' theorem). To that end, we contrasted ID/MT relations for saccades equated for ID but differing with respect to their target amplitudes and widths. Results showed that MT increased with increasing ID within amplitude and width conditions; however, the ID/MT slope was markedly steeper in the former condition. Thus, the amplitude condition imposed greater information processing demands than the width condition-a result indicating that the constituent elements of Fitts' theorem are dissociable (i.e., nonunitary). Further, examination of saccade kinematics demonstrated that the optimal MT for a given target amplitude was largely independent of target width.
authors.affiliation: a School of Kinesiology, University of Western Ontario, London , Canada.|b Graduate Program in Neuroscience, University of Western Ontario , London , Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Heath
authors.affiliation: a School of Kinesiology, University of Western Ontario, London , Canada.
authors.forename: Ashna
authors.initials: A
authors.lastname: Samani
authors.affiliation: c Faculty of Kinesiology, University of Toronto , Toronto , Canada.
authors.forename: Luc
authors.initials: L
authors.lastname: Tremblay
authors.affiliation: d Department of Kinesiology , McMaster University , Hamilton , Canada.|e School of Sport and Exercise Sciences, Liverpool John Moores University , Liverpool , England.
authors.forename: Digby
authors.initials: D
authors.lastname: Elliott
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D011597:Psychomotor Performance / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Fitts’ theorem; movement time; oculomotor; saccade; speed-accuracy