Comparing all six sports against one another, he found the proportion of southpaws increased as the time available for players to act decreased. Nine percent of the top players were left-dominant in the slowest contest, squash, while 30 percent of the best pitchers were lefties in the fastest, baseball. Over all, left-handedness was 2.6 times more likely in the sports with higher time constraints (baseball, cricket and table tennis) than in ones with lower time pressure (badminton, tennis and squash).
His results are couched in a broader “nature” versus “nurture” discussion of why left-dominance may be an asset in sports.
The “nature” hypothesis posits that left-handers may innately be better athletes, perhaps benefiting, for instance, from the fact that the right brain hemisphere is in charge of both their dominant hand and visual-spatial awareness.
The “nurture” explanation suggests that left-handers’ relative rarity gives them a competitive edge because opponents are worse at anticipating their movements or are even used to employing strategies that play directly to lefties’ strengths (hitting balls toward the right in racket sports, for instance).
This “nurture” idea is supported by studies that have found a higher incidence of left-handers in professional interactive sports compared with the general population, but not in non-interactive ones like darts, bowling or golf.
Beyond sports, this explanation could account for why lefties have made up just 10 percent or so of the human population for thousands of years.
“From a Darwinian perspective, there seems to be something wrong with being left-handed,” Dr. Loffing said. “But the question is, why doesn’t it wash out? Why isn’t the world only right-handed?”
In 1996, a team of French researchers proposed that lefties have a fitness advantage in duel-like situations. The same group showed that more violent and warlike traditional societies have a much higher incidence of left-handers than more pacifist societies.
Dr. Loffing believes most of the lefties-in-sports trend can be explained by this so-called fighting hypothesis. His latest research suggests that the benefits portsiders derive from the element of unfamiliarity become greater when their opponents have less time to calculate. “We know that things like anticipation and decision-making are more difficult under time pressure,” he said.
In previous studies, Dr. Loffing and collaborators have shown that athletes can counter or even neutralize the left-sider advantage through training. Next, it would be interesting to combine these two findings and see if there is some time pressure threshold beyond which it would be exceedingly difficult for players to train against the southpaw edge — some threshold “beyond which being rare really pays off,” he said.