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Published on: August 25, 2020
Visually guided, aimed movements can be unaffected by stimulus-response uncertainty
Charles E Wright1, Valerie F Marino, Shane A Belovsky
1Department of Cognitive Sciences, University of California, Irvine, CA 92697-5100, USA. cewright@uci.edu
Experimental Brain Research
|January 24, 2007
Summary
Visually guided hand movements, like saccades, are not slowed by increased stimulus-response choices. This suggests that effector-specific, highly compatible tasks, not privileged pathways, explain the lack of Hick
Area of Science:
- Cognitive Psychology
- Neuroscience
- Motor Control
Background:
- Hick's Law states response times increase with stimulus-response alternatives.
- Exceptions to Hick's Law are rare and theoretically significant.
- Previous research identified exceptions for saccade latencies.
Purpose of the Study:
- To investigate if visually guided hand movements also exhibit an exception to Hick's Law.
- To test the privileged pathway hypothesis for hand movements.
- To explore the role of stimulus-response compatibility and effector specificity.
Main Methods:
- Two experiments were conducted involving visually guided, aimed hand movements.
- Stimulus-response uncertainty and repetition were manipulated.
- Equiluminant stimuli were used in a second experiment.
Main Results:
- Response times for hand movements were unaffected by stimulus-response uncertainty.
- Response times were also unaffected by stimulus-response repetition.
- The lack of uncertainty effect persisted with equiluminant stimuli.
Conclusions:
- Visually guided hand movements do not follow Hick's Law, challenging the privileged pathway hypothesis.
- The absence of stimulus-response uncertainty in hand movements may be due to effector specificity and high stimulus-response compatibility.
- Posterior parietal cortex is unlikely to be the privileged pathway for hand movements.
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