Eye blinking in archers and kendo: Hamaguchi 2012

The study compares eye blinking in 18 university kendo practitioners with 18 students from archery (10) and kyudo (8) clubs during a laboratory reaction task. The aim was to find in the kendo group a trace of zanshin, the attention that stays alert after the strike; the archers serve as a comparison, as people from disciplines that aim at a stationary target.

The archers and kyudo practitioners did not differ on any measure (for instance t(16) = 1.63 for blinks after the warning signal), so they were analysed as a single group. Compared with them, the kendo group blinked neither more nor less after the warning (21.5% against 18.6% of trials) or in the first second after the stimulus, and had the same reaction times (320.9 against 318.3 ms). The difference lay in the following second: the kendo group more often delayed their first blink to 1 to 2 seconds after the stimulus (18.2% and 15.3% of trials, depending on whether they had to respond or hold back, against 10.6% and 7.4% in the archery and kyudo group; F(1, 34) = 10.78).

Only in kendo was this delay related to level, with correlations of 0.73 and 0.71 with the club ranking. In the archery and kyudo group no blink measure was associated with level, with coefficients between -0.22 and 0.15, and neither was reaction time (0.33, not significant).

All participants were right-handed men. The kendo practitioners (mean age 21.1) held 3rd or 2nd dan; the archers (19.7) and kyudo practitioners (20.8) belonged to their university clubs and had no kendo experience. Forty-three started, and seven were excluded because their traces did not allow blinks to be identified. Seated in a shielded room with the right hand on the table, they watched three small LEDs one metre away: the central yellow one lit up as a warning and, two seconds later, one of the two red side lights came on. Depending on the instruction, they had to respond by quickly covering a photoelectric switch with the index finger or hold back (a Go/NoGo task). Each did 12 blocks of three minutes, 260 trials in all.

Blinks were recorded by electro-oculography at 500 Hz, with electrodes above and below the left eye and at the outer corners of both eyes, so that they could be told apart from eye movements. For each trial the authors noted where the first blink fell: in the second after the warning, in the first second after the stimulus, or in the second after that. Competitive level was the athlete's position in his club's ranking: for kendo, the percentage of wins in 51 bouts of the internal league; for archers, the annual mean score in club competitions relative to 720 points; for kyudo, the annual mean hit rate over 20 shots.

The study is built around kendo, and archery enters it only as a point of comparison: ten archers, pooled with eight kyudo practitioners because the two groups did not differ, with no analysis of their own. With numbers this small, the absence of a difference between archers and kyudo practitioners does not show that they behave alike, and a modest correlation with level within the mixed group would have gone unnoticed.

An archer's level is his position in the club ranking, based on an annual mean out of 720, and the ranking in the mixed group sets side by side archers and kyudo practitioners measured in different ways; we are not even told what bows the archers used or how well they shot. The laboratory task, moreover, asks for a quick response to a light, which is far removed from shooting: it describes blinking during waiting and rapid response, not during aiming. The zanshin interpretation, backed by a latent variable model that explains 76% of the variation in kendo level across 18 people, is the authors' reading.

For an archer the useful information is thin and mostly negative. In a waiting and reaction task, blinking did not distinguish archers from kyudo practitioners and was unrelated to their club ranking, while in the kendo group a delayed blink after the stimulus went with higher level. The authors attribute the difference to a kind of training specific to kendo, which demands continued alertness after the strike.

Archery has something comparable in the attention held after the release, but this study does not measure it: it does not record blinks during shooting and does not look at what happens after the arrow has gone. Anyone interested in blinking while aiming will find here only references to older Japanese studies reporting that some experienced shooters suppress blinking for longer on successful shots.