Eye dominance and hand in archery: Laborde 2009 study

The study has two parts. In the first, 82 right-handed sport science students at the University of Caen, 48 men and 34 women with a mean age of 19.3, picked up a bow for the first time: after half an hour of instruction they shot ten arrows at 7 m at a 60 cm face and ten more at a 40 cm face, with a beginner's recurve and no sight. Those whose dominant eye and hand were on the same side, that is right eye and right hand, scored more than those whose left eye was dominant (F = 27.47, p < 0.001).

The differences are not small. On the 60 cm face the men with eye and hand aligned averaged 76.3 points out of 100 against 66.4 for the cross-dominant men, and the women 67.5 against 51.0; on the 40 cm face the men scored 66.6 against 55.6 and the women 53.4 against 40.1. Men outscored women (F = 23.73) and everyone scored more on the larger face (F = 95.31), both at p < 0.001.

In the second part a postal questionnaire to 1,323 French archers, from local to international level, asked about laterality in daily life and laterality when shooting. Among the 1,135 classified by level, the share of cross-dominant archers when shooting is 19.0% at local level, 14.9% at regional level and 19.4% at national and international level, with no difference between levels (chi-square 3.30, p = 0.19); with daily-life laterality the shares are 24.0, 21.5 and 26.5% (p = 0.16). More archers are aligned when shooting than in daily life, 934 against 864: those who changed in order to shoot almost always went from crossed to aligned, keeping the dominant eye and switching bow arm.

The authors read the contrast between the two parts as an effect of the sight, which in trained archers would cancel out the disadvantage seen in beginners. That is an interpretation: in the second part nobody shot an arrow for the study, and in the first nobody used a sight.

The beginners were sport science students who did not take part in any other aiming sport. Only right-handers were included, because just nine left-handers had volunteered, too few to form a group. Hand dominance was set with a French translation of the Edinburgh Handedness Inventory, ten questions on the hand used in everyday actions, which yield a laterality quotient between minus one hundred and plus one hundred; eye dominance with the finger-pointing test, in which the person points at a distant object with both eyes open and then closes one eye at a time. The result was 54 aligned participants, 35 men and 19 women, and 28 cross-dominant ones, 13 men and 15 women.

After the basic rules and thirty minutes of practice, each of them shot ten arrows at 7 m at the 60 cm face and then ten at the 40 cm face, with a beginner's recurve and no sight, scoring from 0 to 10 as in the rulebook. The analysis is an analysis of variance with laterality, sex and face as factors.

The archers in the second part were reached by post, so as to cover the whole country. The questionnaire asked for age, level and years of practice, then daily-life laterality with the same inventory and the same finger test, and laterality when shooting with two questions: which hand holds the bow and which eye does the aiming. Questionnaires with no dominant eye, 72 of them, were discarded, as were those of archers who say they aim with both eyes, 51, because in those cases crossing cannot be established. The distribution across levels is compared with a chi-square test.

Eye dominance is set with a single test, as the authors acknowledge: the finger test is simple, but it is not the most reliable of those used in sport. Among the beginners all left-handers are missing, so the cross-dominant group consists only of right-handers with a dominant left eye, and the study does not say how they aimed: we do not know whether they closed an eye, which one, or what the instructor told them. If they shot right-handed, as the text implies, they anchored the string under the right eye while the left eye was leading, and without a sight the result could depend on that more than on laterality as such.

The test is a first contact: half an hour of practice, twenty arrows, 7 m. It shows who starts with an advantage, not who learns faster, and it does not say whether the disadvantage persists after a few weeks. Effect sizes are not reported, nor is the interaction between laterality and sex, which the means in the table give reason to suspect: on the larger face the gap is about ten points among the men and sixteen among the women (my calculation). In the discussion, moreover, the cross-dominant men become 11 instead of the 13 in the table.

In the second part some figures do not add up: 72 and 51 discarded questionnaires make 123, not the 125 declared, and 1,323 minus 125 gives 1,198, while the table classifies 1,135. Nor is it stated whether 1,323 is the number of questionnaires sent or returned. Above all, the trained archers did not shoot: the study counts how many cross-dominant archers there are at each level, not how well they shoot, and anyone who switched bow arm to shoot is counted among the aligned. That the sight cancels out the disadvantage remains a hypothesis of the authors, which these data do not test.

For anyone starting out without a sight, the combination of eye and hand matters in the first arrows: in these beginners the gap is around ten points out of a hundred among the men and over fifteen among the women, on the 60 cm face at 7 m. It is a finding about people at the very start, collected after half an hour of practice, and it does not say how long it lasts.

Among those who shoot with a sight the picture changes. From local to international level between 15 and 19% of archers shoot with eye and hand crossed, and the share does not fall as the level rises: in this sample being cross-dominant did not stop anyone from reaching the top. Those who changed laterality in order to shoot almost always did so to put the bow on the side that lines up their dominant eye, and hardly ever the other way round.

Two things lie outside these data. The first is whether, at the same level, cross-dominant archers shoot less well, because there are no scores for the practitioners. The second concerns those who shoot without a sight even after years, as in barebow or traditional archery: the disadvantage was seen only in beginners, and the study says nothing about experienced archers who shoot without a sight.