The Difference Between Mixed-Handedness and Ambidexterity

When most people think about handedness, they have two different forms in mind: Left-handedness and right-handedness. Overall, studies that investigated how many people are left-handed and right-handed found that about 10.6 percent of people are left-handed and 89.4 percent are right-handed (Papadatou-Pastou and colleagues, 2020).

But there are more forms of handedness than just left-handedness and right-handedness.

Some studies include a third category called mixed-handedness. While left-handers perform most or all skilled motor activities like writing and drawing with their left hand, right-handers perform most or all skilled motor activities like writing and drawing with their right hand. Mixed-handed people do not have such a clear preference for one side. As the term suggests their preferences are mixed. They might use their right hand for writing and throwing a baseball, but their left hand for drawing and opening the lid of a glass of jam. While there are a few people who identify themselves as mixed-handed, mixed-handers are not as rare as you may think. If only studies that included three categories for handedness were assessed, the percentage of mixed-handedness was 9.33 percent (Papadatou-Pastou and colleagues, 2020).

The riddle of ambidexterity

A further form of handedness is ambidexterity. As the term suggests, ambidextrous people have equal dexterity to perform motor tasks like writing letters with the left and right hands.

Ambidexterity is not the same as mixed-handedness. If you have 10 skilled activities to be performed with one hand, a mixed-hander would have good skills with the right hand for some of them but would have trouble doing them with the left hand. For other behaviors, a mixed-hander would have good skills with the left hand, but trouble doing them with the right hand. A truly ambidextrous person would be equally good with both hands, no matter the task. Despite this difference, mixed-handedness and ambidexterity sometimes get mixed up when people talk about handedness.

Clear criteria for mixed-handedness and ambidexterity

A recent initiative of experts in handedness and other forms of laterality now included suggestions on how to determine ambidexterity (Vingerhoets and colleagues, 2023). In the publication, published in the science journal Laterality, the authors made some interesting suggestions.

Mixed-handedness is typically determined using a preferences questionnaire. In such a questionnaire, people are asked which hand they prefer to perform an activity such as writing. It is, however, not measured whether they are better with the preferred hand. Some people may prefer the right hand and write better with the right hand, but others prefer the right hand but write equally well with both hands. Ambidexterity, as the term implies, refers to dexterity, for example, actual skill not preferences. While mixed-handedness can be measured with a preference questionnaire, ambidexterity can only be determined by using actual skill tests. For example, one could use the alphabet test to determine ambidexterity for writing. In this test, people need to write the alphabet as one word as fast and accurately as possible. An ambidextrous person would be swift and accurate with both hands. Therefore the authors of the initiative paper suggested that ambidexterity can only be determined using performance tests. Moreover, they suggested that ambidexterity needs to be determined separately for different behaviors. For example, somebody can be ambidextrous for writing but not drawing.

How do I know whether I am mixed-handed or ambidextrous?

According to the study, mixed-handedness is an ambiguity in preference while ambidexterity indicates very similar performance abilities with both hands for one specific task. If you want to know whether you are mixed-handed, think of different activities that you can perform with your hands such as writing, drawing, opening a box, using scissors, and so on.

If you tend to use the left hand for some activities and the right hand for others, chances are high that you are mixed-handed. If you only prefer one hand, you are left-handed or right-handed.

If you want to know whether you are ambidextrous, you could for example try out the above-mentioned alphabet test and write the alphabet as one word on a sheet of paper with the left hand and then with the right hand. Measure the time it takes for both hands with your smartphone. If the time is very similar for both hands and the writing looks equally well, chances are you are ambidextrous.