Learning to tie well with others: bimanual versus intermanual performance of a highly practised skill

Abstract

Studies indicate that novices are faster in manual tasks when performing with a partner (‘intermanual’) than with their own two hands (‘bimanual’). The generality of this ‘mode effect’ was examined using a highly practised bimanual task, shoe tying, at which participants were experts. Speed–variability correlations confirmed participants were bimanually skilled but not intermanually skilled. Contrary to results using novices, intermanual was slower, such that prior skill reverses the effect. Analyses incorporating the similarity of shoe-tying strategies across dyads implicated a perceptual rather than shared knowledge/representation basis for intermanual performance. Practice effects indicated that intermanual performance built upon prior bimanual skill, such that novel relative timings between dyads' hands must be acquired. Motor transfer effects provided support for this conclusion. During shoe tying, hands were tightly coupled in the intermanual mode due to the perceptual coupling constraints of intermanual performance. Increased coupling was correlated with slower performance. Implications for real-world tasks (e.g. surgical knot tying) are described.

Abstract

Practitioner Summary: Novice participants perform manual tasks faster with a partner (‘intermanual’) than on their own (‘bimanual’). The generality of this ‘mode effect’ was investigated using a highly practised bimanual task, shoe tying. The mode effect was reversed and mechanisms underlying intermanual skill acquisition were identified. Practical implications extend to tasks such as surgical knot tying.

Keywords::

• coordination
• coupling
• interpersonal
• practice effects
• motor transfer
• recurrence

Acknowledgements

Preliminary findings of this research were published in the Proceedings of the Human Factors and Ergonomics Society 2013 International Meeting (Crites and Gorman 2013). The authors are grateful to Nicole Amos, Kelsey Chomik and Sarah Tsai for assisting with task development and data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

^1. We thank an anonymous reviewer for pointing out these connections between bimanual automaticity and the challenges of intermanual shoe tying.

^2. We are hesitant to say ‘learning’ because demonstration of learning conventionally requires evidence of retention, so we say ‘practice effect’ instead to reflect the task-relevant acquisition of a new or modified skill when the coordination requirements for performing a familiar skill change.

Additional information

Funding

Preparation of this article was supported by the National Science Foundation [grant number BCS 1257112].