28th International Congress of Psychology August 8 ... - U-netSURF

information about the observer's action capabilities (affordances). Infants, children, and adults are
known to use particular types of movements in an exploratory manner, to learn about what they
can do in a given environment or situation. Examples include locomotion, catching, and stance.
1003.3 Rhythmic timing and resonance constraints, D. Sternad, H. Yu, A. de Rugy,
Pennsylvania State University, PA, USA
Three experiments show that rhythmic movements are constrained by the resonance properties of
the moving limb. In our task we manipulate the limb’s inertial properties and determine
metronome frequencies that are longer and shorter than the subject’s resonance frequency. In a
continuation task and two tracking tasks subjects synchronize with the prescribed frequency but
also show systematic deviations such as period drift and phase differences. A model of coupled
oscillations consisting of a neuromechanical level coupled to an external pacemaker via an
internal pacemaker can replicate these features.
1003.4 How do humans deal with variability in the internal/external enviroments to produce
skilled movements? K. Kudo, The University of Tokyo, Tokyo, Japan
Human movements are produced in variable external/internal environments. Because of this
variability (e.g., the amount of neurotransmitter, external forces), the same motor command can
result in quite different movement patterns. Therefore, to produce skilled movements we must
coordinate the variability, not try to exclude it. In addition, because our movements are produced
in the redundant and complex sustem, a combination of variability should be observed in different
anantomical/physiological levels. In the symposium, I will introduce our recent research about
human movement variability that shows remarkable coordination among different levels, and
between the organism and the environment.
1003.5 Accuracy constraints on voluntary movements during standing, M. Duarte,
Universidade de São Paulo, São Paulo/SP, Brasil
Voluntary movements are combined with balance control in many tasks in our daily life. To
perform such tasks, we often have many other constraints and at the same time much more
freedom than we are used to study in a laboratory setting. The present work will discuss one
aspect of this issue: the effects of spatial and temporal accuracy constraints on voluntary
movements during standing. The classical speed-accuracy trade-off paradigm will be exploited to
understand movement and balance control.
1004 INVITED SYMPOSIUM
Attention and perception: Applied Approach
Convener and Chair: J.C. Yuan, Taiwan, China
1004.1 Effects of relative brightness highlighting on target detection performance in a cockpit
display of traffic information, W. Johnson 1 , M.J. Liao 1, 2 , S. Granada 1, 2 , 1 NASA Ames Research
Center, Moffett Field, CA, USA; 2 San Jose State University, USA
This study examined how mixtures of bright and dim aircraft symbols within a cockpit traffic
display affected the search for a target aircraft. The main independent variables were 1) whether
the target was among the bright or dim alternatives, and 2) the target brightness. In one experiment
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