title: Different Faces of Variability in the Adaptive Process of Motor Skill Learning.
abstract: This study investigated the variability by considering an action programme as hierarchically organized, which reconciles invariant and variant features of motor skills at the macro- and microstructural level of analysis. It was assumed that invariant aspects of skilled actions express the macrostructure and therefore measures of sequencing, relative size, relative timing, relative force and relative pause time. The microstructure was related to the variant aspects so that total size, total movement time, total force, and total pause time were selected as its measures. These propositions were tested in an experimental design comprised by three learning phases: a stabilisation phase that entailed a given number of trials to achieve the functional stabilization on a graphic task, followed by transfer and retention phases. In the transfer phase, the graphic task was modified to yield different demands upon skill reorganization. Two such modifications demanded parametric changes (i.e. microstructure changes), in which graphic size and drawing speed were altered. Another modification demanded structural alterations (i.e. macrostructure change), in which drawing was changed. Overall, results supported the main predictions by showing that parametric changes in the task affected the microstructure, but did not affect the macrostructure consistently. Furthermore, a structural change affected both macro- and microstructure.
authors.affiliation: Universidade de Sao Paulo, Brazil.
authors.forename: Umberto Cesar
authors.initials: UC
authors.lastname: Corrêa
authors.affiliation: Universidade Federal de Minas Gerais, Brazil.
authors.forename: Rodolfo Novelino
authors.initials: RN
authors.lastname: Benda
authors.affiliation: Universidade Nove de Julho, Sao Paolo, Brazil.
authors.forename: Dalton Lustosa
authors.initials: DL
authors.lastname: de Oliveira
authors.affiliation: Universidade Federal de Minas Gerais, Brazil.
authors.forename: Herbert
authors.initials: H
authors.lastname: Ugrinowitsch
authors.affiliation: Universidade de Sao Paulo, Brazil.
authors.forename: Andrea Michele
authors.initials: AM
authors.lastname: Freudenheim
authors.affiliation: Universidade de Sao Paulo, Brazil.
authors.forename: Go
authors.initials: G
authors.lastname: Tani