Inclusivity guide: usability design for left handedness 101
By: Ruben Babu
Tags: Usability, User Experience, Accessibility, Product Design, Hci

1 . Make sure you ask your users.

The Ruben’s Paradox (like the Fermi paradox)

If studies and survey’s conducted tell us that 10% people in the word are left handed, then why aren’t all apps and products inclusive of left handedness?

Globally, 10% is a very large group of users. But, this is not uniform across the globe however. It is true that some people in countries like India culturally discourage use of the left hand at a young age and they convert them to right handed users although that is now changing in the developing country. Most middle eastern countries have users who are primarily left handed because they write Arabic, which is a right-to-left script. So this percentage might be lower or higher in some geographies. Also another theory is the kind of work people do.

To quote Mwaniki, Andrew of theworldatlas, “The brain hemisphere associated with speaking and handiwork operates in one sphere instead of it being divided. This theory asserts that left-handed people have a reversed brain division which makes the left-hand more dominant.”

Why aren’t there more inclusive products? One answer to this question could be that you don’t know if you have such users. You haven’t asked this question in your user research process early on. If there are good designers on your team, then it stands to reason that they have conducted some form of user survey or field research where they try to understand the user’s world. Chances are that if you ask your users this question, you will find out that a few left handed users actually exist.

2. Layout of the control surfaces

Buttons on an app, handles on a physical product, or even food or culinary experiences and products like cutlery, microwaves or blenders.

Rock, Paper, Scissors! Easy to design, even easier to get it wrong. Same is true for clothing, industrial equipment and entertainment devices.

Ever wondered why there are keys repeated on both sides of the keyboard? Did you know the mouse controls can be flipped? Why did matchboxes have strike strips on both sides? That’s inclusivity at its best. I think that in the old days, when a lot of things were invented for the first time, designers were more thoughtful and considerate, like the design of a pen — who cares which hand you hold it? it works either way.

Nowadays we’ve all just fallen into the trap of optimising only for primary user base. The other 90%. Gender, Age and Status biases are even more real and I’ll cover them in later articles. In summary, buttons on the far right or the far left is being unfair to the other.

In App UX; here’s a map of how far thumbs reach for both the persuasions.

If you really must put buttons in one of the corners, Consider a wider one that the other user can reach if not possible to tap right at its centre.

Desktop web browsers have buttons on the top left before the URL, so when you make websites, put the main call to actions somewhere at the centre of the cards or information blocks on the page so that neither of the users have to drag their mouse pointer all the way.

3. When in doubt, centre align.

When users approach in a hurry, if they can’t get access, they leave it. This is important if your product is being designed to save lives.

Often products fail that fail their users. If the user cannot approach your product quickly enough or has to go through self-training to use it due to their handedness, you need to re-think the whole thing. Like, measuring cups that do not have the measurements on both sides are terrible to use.

Imagine a fire extinguisher that cannot be used by both hands. Thats the bottom line for the designer’s career and for the poor user, unfortunately :( Luckily there are regulatory systems in place for such things, yet they fail too sometimes and non-inclusive design gets through the cracks in the system.

If you are a product designer or an industrial designer who makes transportation or utilitarian products, this must be on your checklist. Think pull up and pull down interactions rather than pull left or right. Next time you get into your car, notice the door handles. Or a push cart at the shopping mall, or even the emergency exit door handles at any public area.

4. Test with both hands

Go ahead and try to use your product with both the hands separately.

Because we forget. Because we have one side dominant (except those <1% of users who are ambidextrous) we are likely to use our favourite side and not test for this usability.

Remember this list and answer the very real cry for help of all your users. After all, thats the “real why” behind good design.

All you have to do is figure out the how, when and where.