The University of Indianapolis Math Department hosted a lecture through the Mathematical Association of America entitled, “Why Do Left-Handed People Survive?” on Wednesday, Feb. 24. An audience of about 25 students and faculty attended the event. Associate Provost for Faculty Affairs and Professor of Mathematics and Statistics at Valparaiso University Rick Gillman studied the research and statistics of many published experiments and presented his findings in the lecture.
The lecture was chosen from a list sent to the University of Indianapolis by the MAA, according to Associate Professor of Mathematics and Computer Science Krystina Leganza. Leganza, along with most of the math department, is an individual member of the MAA.
“This is the first one [MAA event] we’ve hosted, but we’d like to do one MAA event a year and something a little more local, so one event a semester,” Leganza said.
Gillman first said that despite the title of the lecture, his findings did not support a higher death rate for left-handed people. Throughout the lecture, he used more recent studies to disprove his first example, an experiment that researched the death rates of left-handed people in Los Angeles and claimed that a higher percentage of left-handed people were dying young than right-handed people. Gillman explained that despite the fact that much of the world is purposed for right-handed people, it is not causing left-handed people to die younger.
To speak about right- and left-handedness, Gillman first had to describe handedness and laterality in normal vocabulary, so that even non-math majors could understand. There are more left-handed men than women everywhere, except France, Gillman said. He offered a number of statistics: across the world, there are only about 10 to 20 percent of people in the population are left-handed, and that number has stayed constant throughout time, so far as statistics can tell. Even in identical twins, opposite handedness can occur, but only 10 to 20 percent. In a state of being in which all of a person’s organs are on the opposite side of where they belong, called “situs invertus,” only 10 to 20 percent of those people are left-handed. It is difficult to tell handedness in people because a person may write with his left hand but pitch baseball with his right. Gillman explained that there is no standard measure for determining degrees of handedness, but there are questions one can ask to decide. For instance, what hand do you write with, eat with and throw with?
“There’s right-handedness and then there’s a continuum of stuff that’s non right-handedness,” Gillman said. “There are several theories of left-handedness, but there is no gene out there that makes people left-handed.”
A magazine called “Laterality,” which talks entirely about sidedness, describes that species in general are usually split in half on sidedness. The only ones that are not are humans, horses and chimpanzees, according to Gillman. He discussed left-handed athletes and pointed out that boxers and golfers have a higher percentage of left-handed people, but left-handed rowers are less successful. Gillman said that this is because high-competition areas create a favorable environment for left-handed people, but high-cooperation sports require right-handed people.
“We have to be this way because we’re a highly cooperative species,” Gillman said.
Junior math major Courtney Muston said she is left-handed and attended the event because the topic interested her.
“The most interesting thing to me is that the [10 to 20 percent] number of the population has stayed consistent, no matter what,” Muston said.
Junior math major Kayla Lane, who said she is right-handed also attended the event.
“I liked the graphs that said it just happened to be 10 percent, and it could’ve settled at any number, but it settled at 10,” Lane said.
A good example of the effects of left-handedness is driving in London. Since the English drive on the opposite side of the road, and people naturally turn in the direction of their handedness, more left-handed people turn away from the accidents in England, Gillman said. In the United States, left-handed people turn toward the other car and more head-to-head collisions occur. Language is not kind to left-handed people, either, Gillman said. The Anglo-Saxon word for left, lyft, means weak or broken. The German word means clumsy or uncouth, as does the French.
“When someone says, ‘Oh, you’re left-handed,’ that phrase has never, ever, ever been a compliment,” Gillman said. “It’s always with that condescending, slightly pejorative sense of, ‘Oh, you’re not quite right.’”