Biology subjects

McDougle, S.

Publications and source records attributed to McDougle, S..

2 recordsLinked to original sources

bioRxiv2023

Independent Influences of Movement Distance and Visual Distance on Fitts' Law

Fitts Law is one among a small number of psychophysical laws. However, a fundamental variable in Fitts Law - the movement distance, D - confounds two quantities: the physical distance the effector has to move to reach a goal, and the visually perceived distance to that goal. While these two quantities are functionally equivalent in everyday motor behavior, decoupling them might improve our understanding of the factors that shape speed-accuracy tradeoffs. Here we leveraged the phenomenon of visuomotor gain adaptation to de-confound movement and visual distance during goal-directed reaching. We found that movement distance and visual distance can influence movement times, supporting a variant of Fitts Law that considers both. The weighting of movement versus visual distance was modified by restricting movement range and degrading visual feedback. These results may reflect the role of sensory context in early stages of motor planning. Public SignificanceYou will automatically slow your movement when picking up a needle five inches away versus a handkerchief three inches away. This fact is elegantly formalized by Fitts Law, which mathematically relates movement duration to movement difficulty. However, one of the fundamental variables in the law - the distance of a planned movement - is ambiguous: Is it the actual distance the hand must move that biases movement duration, or is it the visually perceived distance? We decoupled these variables, finding that Fitts Law is shaped by both quantities, and that the influence of one versus the other may be related to the relevance of visual information. We believe our "addendum" to Fitts Law is timely, as everyday motor behavior has become increasingly enmeshed with virtual environments that abstract our movements into digital realities.

neuroscience↗

bioRxiv2023

Metacognitive Judgments during Visuomotor Learning Reflect the Integration of Error History

People form metacognitive representations of their own abilities across a range of tasks. How these representations are influenced by errors during learning is poorly understood. Here we ask how metacognitive confidence judgments of performance during motor learning are shaped by the learners recent history of errors. Across four motor learning experiments, our computational modeling approach demonstrated that peoples confidence judgments are best explained by a recency-weighted averaging of visually observed errors. Moreover, in the formation of these confidence estimates, people appear to re-weight observed motor errors according to a subjective cost function. Confidence judgments were adaptive, incorporating recent motor errors in a manner that was sensitive to the volatility of the learning environment, integrating a shallower history when the environment was more volatile. Finally, confidence tracked motor errors in the context of both implicit and explicit motor learning, but only showed evidence of influencing behavior in the latter. Our study thus provides a novel descriptive model that successfully approximates the dynamics of metacognitive judgments during motor learning. NEW & NOTEWORTHYThis study examined how, during visuomotor-learning, peoples confidence in their performance is shaped by their recent history of errors. Using computational modeling, we found that confidence incorporated recent error-history, tracked subjective error-costs, was sensitive to environmental volatility, and in some contexts may influence learning. Together, these results provide a novel model of metacognitive judgments during motor-learning that could be applied to future computational and neural studies at the interface of higher-order cognition and motor control.

neuroscience↗