Why we get left and right confused
This post was originally written in November 2019 and was updated in December 2024.
When I was doing my MSc, I spent six months working as a research assistant in the lab of the man who would later become my PhD supervisor, Jamie Ward (now Professor of Cognitive Neuroscience at the University of Sussex). Back then, he worked at University College London, or UCL, which is in central London.
I spent quite a lot of my time at UCL running a series of experiments to understand the links between our perception of colour and our perception of touch. This eventually became my MSc thesis and then part of a chapter in a book.
In an early meeting, Jamie told me that if I had people who weren't familiar with University College London coming in to do experiments, it was very important that I go to meet them. This was because most people were coming in by public transport and getting to the lab from the nearest tube station involved a left turn and then a right turn.
“You wouldn't believe how many people have got lost on the way here because they mix up left and right,” he said.
We were in a pre-smartphone era, which explains why no-one was using Google Maps and also why my evening job was working for a text message question answering service, at which people could and would text us things like “Can you milk a dolphin?” and we would text back with an answer.
Back to the point. The irony was that I am one of those people who struggle with left and right. These days, I get it right about 95% of the time, but unfortunately that means people think I can be relied on and they only learn the error of their ways when I shriek, “NO, THE OTHER LEFT!!!!!” as we zoom past our destination.
What’s going on?
Getting left and right correct might seem like a very simple thing if you can do it with no problems yourself. If that's true of you, then congratulations, because it’s a really complex task due to the number of different processes involved.
These are:
Integrating information coming in through your senses to make a coherent understanding of the world
Recalling that ‘left’ and ‘right’ are meaningful categories we can use to communicate
Figuring out which side of the object we want to refer to
Remembering which way round the labels are
Amazingly, we generally get steps 1-3 correct, even though they are pretty complex. Step 4, which seems like it should be simple, is the one that tends to break down.
Some of the problem is that the way we learn left and right, at least in Western cultures, is a pretty haphazard affair. To understand exactly why this is a problem, let me first of all introduce you to two different ways of talking about space, also known as frames of reference:
Egocentric frames of reference are ones that rely on your location.
Allocentric frames of reference are ones that don’t rely on your location.
You can tell the difference between an egocentric and an allocentric frame of reference with a simple trick.
Point left! Now do a 180 and point left again. You should be pointing in a different direction, because you are carrying your own personal definition of ‘left’ around with you. ‘Left’ and ‘right’ are therefore part of an egocentric reference frame.
Point north! Now do a 180 and point north again. You should still be pointing in the same direction as you were before, because ‘north’ has nothing to do with the way you are facing. 'North’ and ‘south’ are therefore part of an allocentric reference frame.
In everyday British English, we typically tend to say things like “on the left side of the room” or “in your right hand”. Because we use ‘left’ and ‘right’ so much, we can tend to lose sight of the fact that they’re pretty ambiguous terms. Whose left? Whose right?
If you are in the process of learning English, you might or might not realise that ‘left’ and ‘right’ depend on the speaker. And because the person teaching you English is almost certainly fluent, they might not be thinking about this either. So a kid learning English, or any other language that uses egocentric reference frames, is facing a tricky task in figuring out what these terms actually mean. It can take much longer than you might think: in one study with kids in France and New Zealand, the researchers found they could get left and right on their own bodies correct almost every time by seven years of age, but were still confused about left and right on other people’s bodies at the age of eleven.
If this is a problem faced by a kid you know and you want to help them, then the first thing you might want try is something very simple: explicitly tell them what ‘left’ and ‘right’ refer to, rather than leaving them to figure it out for themselves.
This advice is based on a delightful experiment in which the researchers taught four-year-old native speakers of English two completely made-up directions, ‘ziv’ and ‘kern’.
When the kids were told things like “this is the ziv side of the room”, or “this is the ziv side of your body” they tended to interpret it as an allocentric statement – which is fair enough. Those statements are ambiguous and could be allocentric or egocentric. However, when the kids were explicitly told that ‘ziv’ and ‘kern’ referred to different sides of their bodies, they quickly picked up that they were egocentric terms.
It’s probably not about gender
Okay, so labelling left and right is trickier than knowing left and right for children. But we still end up with some adults who are really good at labelling and some who are really bad, so there must be something else going on.
One possibility is whether a passing psychologist would throw you in a bin marked ‘male’, in a bin marked ‘female’, or in a bin marked ‘not in my study’. In more science-y terms: I am generally wary of studies looking at sex differences, because they tend to exclude intersex and trans people and they often conflate sex and gender. It can also be misleading to make broad generalisations about such differences given that there can often be more differences within a sex than between sexes. As a very basic example, personality-wise I am more like my dad (a bookish man who incessantly makes bad puns) than my mum (an extrovert who likes photography and splashing about in rivers).
So, now you know why this is a silly question to ask, what is the answer? Well, there’s quite a lot of research out there on whether men or women are better at telling left and right apart, but after all those caveats… it’s not at all conclusive.
It’s almost like asking ‘is this a thing that women/men/nonbinary people do?’ is generally not very helpful when it comes to psychology.
The serious business section: medicine, flights and strokes
Near the beginning of this blog I mentioned that I now get left and right the correct way round about 95% of the time. There are many other people who get left and right confused at least some of the time, because humans are not perfect. Not even Mr The Rock is perfect, though I admit he is probably the closest we’re going to get as a species.
So… what circumstances make it more likely that someone will mix up left and right? A lot of the research I found on this problem came from studies done with medical students in Northern Ireland, where there is a group of researchers who are really interested in why and how doctors get left and right mixed up. This kind of mix-up doesn’t happen that often in medicine, but when it does the results can be really serious. Imagine you need an operation on your right eye, but when you come round you find it’s your left eye that’s been operated on.
Medicine as a profession is, apparently, very bad at acknowledging that these kinds of human errors can occur compared to other industries – like aviation – where getting left and right mixed up could be equally serious. However, research is starting to reveal what kinds of things can lead to left-right errors in medicine, including stress, fatigue, language barriers between medical staff and patients, senior staff making it difficult for junior staff to challenge errors, and even subtleties like the lighting being better on one side of the room than the other. Distraction can also be a problem – not the background noise of being in a hospital so much as being interrupted with information that needs to be attended to.
Thankfully, there are now protocols in use to prevent these kinds of medical errors, like double-checking you’re doing the correct procedure in the correct area of the body on the correct patient, time-outs before a procedure, and marking the site for the procedure with a Sharpie. Obviously, mistakes can still happen, like a nervous, sweaty patient rubbing their hands together and accidentally transferring a mark from one hand to another. But they should be much less likely with these kinds of protocols.
Lastly, sometimes getting left and right confused can be a sign of a serious problem for the person it’s happening to. While many of us get left and right confused every now and then in the course of our everyday lives, if it happens suddenly to someone who’s been fine at it before it can indicate a neurological condition called Gerstmann’s syndrome, which is normally the result of a stroke damaging the left parietal lobe, though sometimes it can happen with damage to another area of the brain.
During a stroke, blood flow to part of your brain is reduced or cut off. The lack of blood causes nearby brain cells to stop working and those cells will begin to die. The quicker you can treat a stroke, the fewer cells will die – so knowing stroke signs is a very good idea.
There are three major signs that happen in a lot of strokes, which you might be familiar with from the FAST test.
However, because strokes can affect different areas of the brain, not everyone who has a stroke will have any or all of these signs. This is where knowing the signs of Gerstmann’s syndrome is helpful:
Suddenly getting left and right confused.
Sudden inability to write, or serious trouble writing.
Sudden severe difficulty with doing simple calculations like 5 + 3.
Suddenly getting confused about which finger has which name, like being unable to tell which is your index finger and which is your middle finger.
Each of us varies in how good we are at these four things so you’ll need to take that into account, but if any of these happens suddenly and to a degree that’s unusual for you, call an ambulance.