Bilateral Transfer is grasping a skill with both hands. It refers to the idea that we are better able to acquire a new skill, if we practice with both our dominant and non-dominant hands. A number of experiments support this theory (Halsband & Lange, 2006. Senff & Weigelt, 2011. Stöckel & Weigelt & Krug, 2011).
Some context:
I’ve only recently discovered the term bilateral transfer, but I’ve been working with it for years. When I first started delivering welding classes, I wanted to make sure I was able to easily perform any weld I might encounter in the field. So, I practiced to a goal of perfection.
At one point, while struggling to complete, I used my non-dominant hand out of desperation. My success was not great, but when I went back to my dominant hand, I found improvement. From there, I incorporated the practice into my curriculum. Any time a student struggled to make a weld, I’d suggest they try with their other hand. It has usually provided positive results.
I explain it to the student this way: There are three advantages to using your opposite hand. Firstly, it’s like you’re creating a second pathway to the same end. By using your other hand, you activate the other side of your brain, and build new connections (bilateral transfer). Second, because you’re doing something new, you spend a bit of time thinking about how you do that, how you are going to do it in mirror, and then take any discoveries back to your dominant hand (critical reflection (Brookfield, 1991)). Thirdly, I tell them it doesn’t matter if they succeed or not. They are at the disadvantage of using their non-dominant and unpracticed hand, any expectation of a better result is unrealistic. Have some fun with it (gamification).
The Evidence:
One of the studies that looked at bilateral transfer, focused on the sequential effects of practicing with either the dominant or non-dominant hand, before being tested with the dominant hand (Senff & Weigelt, 2011). They found that those that first practiced with their non-dominant hand, then their dominant hand (nd/d), showed greater ability than those that practiced with their dominant hand, then their non-dominant (d/nd). Similarly, the nd/d group outperformed those that practiced exclusively with their dominant hand (d/d). It was also noted that those that practiced with only their non-dominant hand (nd/nd), ranked second in terms of performance.
Another set of experiments then evaluated the sequential effects of using both hands to practice, but evaluated the performance of both the dominant and non-dominant hand (Stöckel & Weigelt & Krug, 2011). They found similar result, with the nd/d group showing greatest improvement with both hands, and the second ranked was a group that switched back and forth between the dominant and non-dominant hand while practicing.
In terms of brain activity, functional studies (Halsband & Lange, 2006) show that the spatial region of the right hemisphere is used in early skill acquisition, while the left brain motor associated areas engage later, as the skill is refined and practiced. The sequential effect on practice was also examined, with those participants who practiced with their right hand then their left (d/nd), showing activity linked to mirroring activities, while those that practiced left to right (nd/d), demonstrated the transfer of spatial information.
This fits with the results of an experiment where participants were tasked with two activities, one requiring accuracy, and one requiring strength (Stöckel & Weigelt, 2012). In both cases, the groups were trained either d/nd, nd/d, d/d, or nd/nd. In the accuracy test, the nd/d group scored best, as spatial reasoning was the critical learning. In the strength test however, the d/nd came out on top. This could be attributed to the natural tendency for greater strength in the dominant hand.
Conclusion:
All of the participants were right-handed. So, these studies indicate that it may be advantageous for right-handed individuals to begin all motor skill learning with the left hand, for the gain in spatial awareness, before shifting to the right hand for refinement of the motor skill and completion of the task (nd/d). It also suggests that left-handed individuals make acquire skills faster, but could be out paced by their right-handed peers over the long run, as the brain activity shifts from the right to left hemisphere. Further extrapolation- left-handed learners should begin with their left hand, move to their right hand to help refine the motor skill, then back to their left/dominant hand for completion (d/nd/d).
Going forward, I will test these theories in the shop. Armed with a better understanding of how the brain works, my goal will be to further incorporate this strategy into my delivery, and identify the point at which point students should migrate to their other hand.
Try it out. Let me know what you think.
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Brookfield, S.D. (1991). Using critical incidents to explore learners’ assumptions. In J. Mezirow and Associates. Fostering critical reflections in adulthood, 177-193. San Francisco: Jossey-Bass.
Senff, O., & Weigelt, M. (2011). Sequential effects after practice with the dominant and non-dominant hand on the acquisition of a sliding task in schoolchildren. Laterality, 16(2), 227–239. https://doi.org/10.1080/13576500903549414
Stöckel, T., Weigelt, M., & Krug, J. (2011). Acquisition of a complex basketball-dribbling task in school children as a function of bilateral practice order. Research quarterly for exercise and sport, 82(2), 188–197. https://doi.org/10.1080/02701367.2011.10599746
Halsband, U., & Lange, R. K. (2006). Motor learning in man: a review of functional and clinical studies. Journal of physiology, Paris, 99(4-6), 414–424. https://doi.org/10.1016/j.jphysparis.2006.03.007
Stöckel, T., & Weigelt, M. (2012). Brain lateralisation and motor learning: selective effects of dominant and non-dominant hand practice on the early acquisition of throwing skills. Laterality, 17(1), 18–37. https://doi.org/10.1080/1357650X.2010.524222
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