A joint study between the University of Liverpool and the University of Miami has found a statistical correlation between handedness and cognitive ability in mathematical reasoning. According to a news release published by the University of Liverpool, the study involved asking random participants between the ages of 6 and 17 years to complete mathematics questions and other problem-solving tasks. The study found that the most lateralized individuals, meaning those who prefer one side most strongly, have a slight decrease in mathematical ability. However, the researchers found that left-handed males in this age group tend not to follow this trend.
One of the principal researchers in the study, Liverpool psychologist Giovanni Sala, states that while the experiment found a statistical correlation, the link between handedness and mathematics is not enough to be definitive yet:
This study found there is a moderate, yet significant, correlation between handedness and mathematical skill. Moreover, the amount of variance in the maths scores explained by handedness was about 5-10%, a surprisingly high percentage for a variable like handedness.
Researching handedness, or laterality, can be difficult on an empirical level due to the fact that handedness is the product of deep, hard-wired connections in the motor cortex. Studies like the one above rely on a questionnaire called the Edinburgh Handedness Inventory, which asks a series of questions in order to ascertain a degree of laterality. Since the Edinburgh Handedness Inventory relies on self-reported answers to predetermined questions, the margin of error can be high.
Previous studies of laterality have found that in almost every human population, an overwhelmingly large majority of people are right-handed, yet the reasons behind this trend are still unknown. Misconceptions and contradictory data surround the conversation about hand laterality and brain lateralization, making discussion of the topic often veer into pseudoscience or conjecture.
Studies that seek to find connections between handedness and cognitive skills are not new to the neuroscience or psychology worlds. Previous experiments have found connections between handedness and spelling ability, verbal aptitude, and even brain structure. Despite these studies finding some levels of correlation between handedness and cognitive skills, the exact relationship between the two remains a mystery.