How can I become ambidextrous

Ten percent of people are "two-handed"

Clear majorities: Humans remain the only animal in which right-handers have a clear majority: Only around ten percent of all people are real left-handers, but a further ten percent seem to be two-handed, as is the case with the largest meta-study on this topic with 2.4 Millions of participants confirmed. It has not yet been clearly clarified whether the "two-handed" are by nature or whether this is due to cultural influences.

Whether writing, holding a cup or screwing in a screw: The majority of people use their right hand for such activities, and estimates suggest that only ten to 15 percent are left-handed. Researchers have only partially clarified why this is so. There seems to be a genetic basis for the deviating handedness, but prenatal influences and even the season of birth obviously play a role.

Around ten percent are real left-handers

But how many people are left-handed? Marietta Papadatou-Pastou from the University of Athens and her colleagues have now examined this in the most extensive meta-study on the subject to date. To do this, they evaluated the data from five meta-analyzes with almost 2.4 million participants, whose handedness had been examined in studies during various activities.

The result: "The best estimate is a total of 10.6 percent left-handedness," report the researchers. However, the exact number also depends on how strict the criteria for handedness are: Is it enough to write with the left hand or do all other activities have to be done with the left hand as well? If the most stringent criteria are used, the proportion of left-handed people is 9.34 percent, and if the criteria are less strict, 18.1 percent are not right-handed, according to the scientists.

These figures confirm the unusually large majority of right-handed people in humans compared to the animal kingdom. Because with most species of monkeys and other animals, the handedness is much more balanced. Most of the time, the proportion of right-handed and left-handed people is roughly equal.

Another ten percent are two-handed

Also interesting: In addition to the real left-handers, there also seem to be real "two-handed" people - people who use different hands for different tasks. "If you assume three categories - left-handed, ambidextrous and right-handed, then the proportion of ambidextrous people is an estimated 9.33 percent - that's almost as many as left-handed people," report Papadatou-Pastou and her colleagues.

According to the researchers, this underscores that there is a much larger group of people who prefer different hands depending on the task. Whether these are left-handed people who have adapted to at least some of the activities due to socio-cultural influence, as assumed by Leonardo da Vinci, for example, or whether these people are by nature ambidextrous, remains to be investigated. (Psychological Bulletin, 2020; doi: 10.1037 / bul0000229)

Source: Ruhr University Bochum

April 15, 2020

- Nadja Podbregar