Blind archers and touch: Coudereau 2006 study

Ten blind archers in the B1 category, competing at regional level with two or three training sessions a week, and ten blind men who did no archery or shooting, all right-handed and aged between 29 and 57, carried out a touch task: finding the centre of balsa sticks 14 to 34 centimetres long with one finger. The authors expected the archers to be more precise, and the opposite happened.

The archers made larger absolute errors (mean 1.23 against 0.98, with the paper not stating the unit explicitly), but the difference was significant only with the right hand starting from the left end. Above all, the archers placed the centre to the left (mean -0.27), while the non-archers showed no shift (0.04): this is pseudoneglect, the slight leftward shift of the perceived centre usually seen in sighted people. In both groups the right hand shifted the centre to the left and the left hand to the right, and the starting side did the same: starting from the right ended up to the left, and vice versa. Shorter sticks produced smaller errors.

Each stick was fixed to a board with its centre aligned to the participant's body axis, and a semicircular cut-out kept the participant in position. Blindfolded, the participant started at one end, ran the finger along the stick and back three times without stopping, and then pointed to the centre; a needle fixed to the index finger allowed the error to be read to the nearest millimetre, negative to the left and positive to the right. Hand, starting end and length were drawn at random on every trial, giving 40 values per person, and the analysis compares group, hand, starting end and length in a repeated-measures ANOVA. The archers trained with a method based on sound cues; in both groups the causes of blindness varied, and in most cases sight loss had begun in childhood.

Twenty people, ten per group, and a single laboratory task. The paper does not say how long the archers had been shooting, with what equipment or what they scored, and the comparison group is defined only by not practising a precision sport: age at onset of blindness, daily activities and manual habits could explain the difference as well as archery could. The study is cross-sectional, so the idea that archery causes the leftward shift remains the authors' hypothesis, as does their proposed explanation, the attention paid to the bow arm in left-hand space. The authors themselves note that the task is sensory and close to the body, whereas shooting works on a distant target. The unit of the mean values is not clearly stated.

For someone who shoots, the study offers nothing practical: it concerns how blind archers represent nearby space through touch, not how they aim. Its interest is more theoretical: it suggests that years of practice in an asymmetric sport, where a right-handed archer's bow arm works on the left, might leave a mark on spatial perception, and that this mark does not amount to greater precision. For coaches of visually impaired archers it is a curious finding, but with ten archers and no shooting measure it supports no conclusions.