A concept as basic as the hand we choose for eating, writing, making contact with our loved ones, is at the heart of extensive empirical research. Roughly nine in ten of us favor our right hands for these and other tasks, while the tenth either favors the left or, much more rarely, is ambidextrous. Handedness is defined as “the preferential use of one hand for most fine manual tasks. Right handedness is the preferential use of the right hand while left handedness is the preferential use of the left hand.” It is one of those things that the right-handed among us may not think much about, unless they happen to love a lefty.
Historically, the world has not been kind to that tenth person, to the concept of “left.” For instance, some ancient and indigenous cultures view/have used the left hand for “unclean” tasks, frowning on the use of that hand for human interaction. Additionally, in the Bible, Matthew 25:31-46 chronicles what will happen on Judgment Day: “When the Son of Man comes in his glory, and all the angels with him, he will sit on his glorious throne…and he will separate the people one from another as a shepherd separates the sheep from the goats. He will put the sheep on his right and the goats on his left. Then the King will say to those on his right, ‘Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world…’ Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels.” Pretty intense!
Less direly, many household items and modern contexts favor people who are more comfortable using their right hand. Tools like scissors, baseball gloves, and guitars are physical manifestations of the assumption that a given user will be right-handed; this is not unreasonable given the aforementioned percentage of lefties. But while research is inconclusive on whether lefties die more frequently as a result of accidents related to using tools that are designed for the hand they are less comfortable using, these issues can be a nuisance
A New York Times article from earlier this year notes, that the stigmas noted above, as well as the tendency to try to “fix” lefties by making them use their right hands for tasks for which they naturally want to use the left hand, have largely dissipated. What have persisted, however, are questions about correlations between handedness and conditions like schizophrenia; handedness and risk of death from accidents; causes of handedness; whether there is an evolutionary advantage to being right-handed that would explain the prevalence of righties in the population; and, conversely, whether there is an evolutionary advantage to being left-handed that would explain the persistent minority of lefties.
There are some sports-related benefits to being left-handed. Left-handed batters line up on the side of home plate that is closer to first base, while right-handed batters have to line up on the far side. Left-handed tennis players put an unexpected spin on the ball, and their forehand, which is more powerful than the backhand, comes in at a different angle than a rightie’s forehand. Rocky Balboa had an advantage because he was a southpaw boxer.