Yvonne Steggemann

Selective effects of motor expertise in mental body rotation tasks: Comparing object-based and perspective transformations

Brain imaging studies provide strong evidence for the involvement of the human mirror system during the observation of complex movements, depending on the individuals motor expertise. Here, we ask the question whether motor expertise not only affects perception while observing movements, but also benefits perception while solving mental rotation tasks. Specifically, motor expertise should only influence the performance in mental body rotation tasks (MBRT) with left-right judgment, evoking a perspective transformation, whereas motor expertise should not affect the MBRT with same-different judgment, evoking an object-related transformation. Participants with and without motor expertise for rotational movements were tested in these two conditions in the MBRT. Results showed that motor experience selectively affected performance in the MBRT with the left-right judgment, but not with same-different judgment. More precisely, motor expertise only benefited performance when human figures were presented in (for non-experts) unfamiliar, upside-down body orientations.

Täuschungshandlungen im Sport

Deception in sports: An experimental study on the effect of different frequency distributions on head fakes in basketball Abstract. In sports, many athletes use head fakes to hide their true intentions (e. g., when passing the ball to a team colleague). A recent study by Kunde et al. (2011) showed that the opponents gaze direction is processed more or less automatically, slowing down the identification of the pass direction, if pass direction and gaze direction are incongruent (i. e., head fake). The present study investigates whether the frequency with which head fakes are presented modulates their efficacy. Participants should take longer to respond to a head fake (i. e., larger fake effect) when the fakes are used less often and should respond more quickly (i. e., smaller fake effect), when fakes are used more often. In Experiment 1, participants were presented with a static picture of a basketball player performing a chest pass to the left or right. Gaze direction could be the same (congruent conditions) or differ- ent (incongruent conditions) to the pass direction. Participants were asked to respond to the pass direction as fast as possible. In Experiment 2, two static pictures were presented in close succession, inducing the perception of apparent motion in the observer. The number of head fakes was varied across three blocks of trials (25 %, 50 %, and 75 % head fakes). Both experiments showed that the fake effect decreases when the head fake is used more often. Furthermore, Experiment 1 indicated (and Experiment 2 at least in a numerical sense) a reduced fake effect when the head fake was repeated twice. These findings have important implica- tions for sports practice, especially when it comes to instructing players about the tactical use of fake actions.