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Is Fitts' law continuous in discrete aiming?
Rita Sleimen-Malkoun1, Jean-Jacques Temprado, Raoul Huys
1UMR 7287 Institut des Sciences du Mouvement E.J. Marey, CNRS and Aix-Marseille Université, Marseille, France. rita.sleimen-malkoun@univ-amu.fr
Plos One
|July 21, 2012
Summary
Fitts' law
Area of Science:
- Human motor control
- Human-computer interaction
- Cognitive psychology
Background:
- Fitts' law describes a continuous linear relationship between movement time and task difficulty (index of difficulty; ID) in rapid aiming.
- Recent studies observed a discontinuity in reciprocal aiming tasks, suggesting a shift between dynamic regimes at critical ID.
- The nature of this discontinuity in discrete aiming tasks remains less understood.
Purpose of the Study:
- To investigate the presence and nature of Fitts' law discontinuity in discrete aiming tasks.
- To determine if manipulating target width or distance affects the observed discontinuity.
- To explore the implications of Fitts' law discontinuity for understanding neuro-muscular adaptations and the speed-accuracy trade-off.
Main Methods:
- Participants performed discrete aiming tasks with varying index of difficulty (ID).
- Experiment 1 manipulated ID via target width.
- Experiment 2 manipulated ID via target distance.
Main Results:
- A discontinuity in Fitts' law was observed in discrete aiming when ID was manipulated via target width.
- No discontinuity was found when ID was manipulated via target distance.
- The findings suggest the discontinuity is sensitive to how task difficulty is modulated.
Conclusions:
- Fitts' law discontinuity is a robust indicator of neuro-muscular-skeletal system adaptations to task demands, irrespective of task type (reciprocal vs. discrete).
- The results highlight the importance of target width in modulating discrete aiming dynamics.
- This research offers new insights into the dynamic regimes governing discrete aiming and sensori-motor control.
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