Hello and welcome
to this edition of the ILO's Future of Work podcast,
I'm Sophy Fisher.
The 13th of August is International Left-Handers Day.
The aim of the day is to raise awareness of the everyday issues that lefties face
as they live in a world designed overwhelmingly for right-handers.
I know this because it includes me.
With me today is Dr. Marietta Papadatou-Pastou,
assistant professor at the National and Kapodistrian University of Athens.
Marietta led the team behind the largest ever meta-analysis of human handedness.
It included data from more than two million people.
Marietta, welcome, and thanks for joining us
on The Future of Work Podcast.
Marietta Papadatou-Pastou: Thank you very much for inviting me.
It's always a pleasure to talk about left-handedness.
Sophy: Great. I suppose the first question I have to ask you is
are you also a left-hander.
Marietta: No. I'm afraid I'm just a boring right-hander,
[laughs] but I have been working in the field of left-handedness
for more than 15 years now.
Sophy: Right. One of the things that was fascinating about your survey,
your study, that I read,
was that you looked not only at left-handers and right-handers
but there's a large group in the middle of mixed-handedness.
Tell us about that.
Marietta: Exactly, that is correct.
One would typically think that
being a left-hander is just a yes or no question,
I'm a right or a left-hander,
but actually, we know that this is not true.
Handedness is a continuum.
You lie somewhere between being a strong left-hander
to being a strong right-hander.
One can use their right hand for every activity or their left hand,
but there's people in the middle too.
Some people use their left hand for some activities
and their right hand for some other activities.
There's also some people who we call ambidextrous,
who might be equally skilled with both hands
for the same activity.
There's mixed-handedness and there's also ambidexterity,
which is not exactly the same thing.
There's a lot of different ways
one can be left or right-handed or mixed-hander.
More strongly, more weakly, or somewhere in the middle.
Sophy: What did you find was the prevalence of left-handedness?
A figure often quoted is about 1 in 10 people.
Is that what you found?
Marietta: What we did is called a meta-analysis,
as you also used this term.
Meta-analysis is actually
a way to combine, to integrate all previous findings.
We managed to locate 200 studies
and we extracted 262 data sets from those studies,
including actually more than 2 million individuals.
We found best estimate,
an overall estimate of 10.6% for left-handedness,
but the question is more complicated.
We also tried to see
how that translates into more specific things.
For example, when we only looked at handedness
as which hand one writes with,
then this number drops to 9.29%.
It's also interesting how there is a geographical variation
when it comes to left-handedness.
Again, it's not just a simple 10% figure,
even though this number seems to capture reality quite well.
When we looked at studies
that had included participants of European ancestry,
then we found a higher prevalence.
We found a prevalence of 11.12%,
but when we only looked at studies
that had included participants of Sub-Saharan African ancestry,
then we found a lower prevalence,
Even lower when participants were of East Asian ancestry,
We thought this is quite interesting.
Sophy: Why do you think that is?
Do you think that's just different gene pools or what?
Marietta: Yes, that could be one of the explanations.
We thought that it could be either genetics, as you've said,
or the fact that we know that handedness might or might not,
we're not very clear on that in the academic literature,
it might have some sort of correlation with prenatal testosterone levels.
We know there's geographical variations in that,
or it could be due to cultural factors.
We favor this last explanation, actually,
because studies have shown that participants coming from families
with backgrounds with low percentages of left-handedness,
for example, Asian countries,
but have been raised in the Western world,
they show similar prevalence of left-handedness
as the population of the country they have been raised in.
This might happen
because of direct instructions by parents or teachers
or because non-explicit model learning,
so maybe it's the fact that we found lower prevalence of left-handedness
in those cultures
might be exactly because of cultural pressures
to use the right hand,
so the left hand is not considered proper or correct to say it in another way.
Indeed, this cultural hypothesis is supported by data.
For example, in a recent study,
by Zheng et al,
they showed that non-right-handedness in Hong Kong was 8%,
which is higher than in most previous studies in Asian populations.
This could be because of the greater Westernization in Hong Kong
compared with many other Asian areas.
I guess culture has something to do with this variation.
Sophy: It could also be some form of discrimination.
I recall that certainly in European cultures,
there is long-standing historical discrimination
For example, simply the use of the word sinister
in association with left-handedness,
and I can also recall cack-handed, which is usually applied to left-handers,
but which is a pretty disparaging term.
You think that's also the case in other cultures?
Marietta: Oh yes, this is most definitely the case.
We have numerous examples
in different languages, in different religions,
in different cultures around the world,
where being left-handed is considered something negative.
Think of English,
you already talked about the word sinister,
but the word right also stands for correct or proper,
and the same in German, recht is both right,
as in towards the right direction
or the correct thing.
In Vietnamese, for the word right, again, it also means correct or must,
and the word for left also means wrong.
Even in Greek, which is my native language, we use,
sometimes, the word zervos that comes from zavos,
and this word represents stupidity or weirdness.
Even in Chinese, we know that
the left path is sort of the immoral path for one to take.
As I said, there are numerous examples
in many languages across the world
that have words with negative connotations when we talk about left-handers.
Also, religions and cultures.
Let me just give an example from Christianity.
We know that the right hand of God is the favorite hand.
For example, Jesus sits at God's right side.
God's left hand, however, is the hand of judgment,
and when it comes to other forms of discrimination,
we know that homosexuals in the 19th century Europe
were referred to as left-handed
or black magic was sometimes referred to as the left-hand path.
The list goes on and on and on.
Sophy: There is a long history of discrimination against left-handers
and children being encouraged to swap their handedness and so forth,
but what I'm interested in, in the context of this podcast is,
what effect does this have on people when they enter the workplace?
Are there disadvantages or indeed possibly advantages
that we see in the workplace?
Marietta: This is a very good question,
and it's a good question
that has received surprisingly little attention
in the research literature.
Nonetheless, from what we do know,
this question, the question of whether or not
handedness plays a role in workplace
injuries, for example,
it cannot be summarized with a simple general statement
because there seems to be pros and cons to it.
For example, we know that left-handers, as a group,
they tend to perform better with their non-preferred hand
compared to right-handers
and as well as right-handers with their preferred hand.
Sophy: You mean me as a lefty my activities with my right hand
are better than the way that a right-handed person would perform
with their left hand?
Whereas your left hand is as skilled as a right-hander's right hand.
This fact has even supported the suggestion
that left-handers are more employable than right-handers
because they're more flexible
and easier to adjust in the workplace than right-handers,
but also because of this performance asymmetry between the hands.
This asymmetry is less for left-handers.
This does not mean that there are no disadvantages involved
in being a left-hander in the workplace though,
but those disadvantages do not come
from an inherent disability of left-handedness.
It mostly comes from the circumstances in which left-handers are told to work.
If I am to give a more elaborate answer
to whether left-handedness confers or not disadvantage in the workplace,
then we will need to look
into the workplace demands of its occupation.
Clearly, there is no time for that,
or enough data, I should add,
to discuss each and every single occupation.
Let me give you a few examples.
I'd like to talk about surgeons,
workers in the metal manufacturing industry,
woodworkers who operate electric saws, office workers, and professional athletes.
Sophy: I have to say the prospect of being operated on
by a left-handed surgeon
using right-handed tools is rather an alarming one.
Does it actually make any difference?
Marietta: Yes, I think it should.
Let me talk to you about the study
published in the Journal of Current Surgery.
There, participants were 68 surgeons from New York City,
and they were surveyed in their experiences
on being a left-handed surgeon.
This survey showed
that nearly half of the left-handed surgeons surveyed
were anxious about their laterality-related difficulties
in that they sought advice during surgical residency,
but only 1 in 10 programs mentored for laterality dominance.
Moreover, only 13% of the programs provided left-handed instruments
during surgical residency.
-Oh my goodness. -This resulted in surgeons
who considered leaving surgery at some point in their career,
and one surgeon who considered changing specialty
because of left-handedness-related frustrations.
This paper was published back in 2004,
but more recent reviews published in 2010 and 2017 s
howed that this and other issues still remained.
Left-handedness still produces anxiety in residents and their trainers.
There is lack of mentoring on laterality.
There is lack of surgical instruments,
both conventional and laparoscopic,
instruments that are not adapted to left-hand use,
and there is significant pressure to change hand laterality during training.
Left-handedness is considered to be a disadvantage
when it comes to surgical training,
but as I said earlier,
these are not due to inherent lesser ability
on behalf of left-handers.
Sophy: Okay. What about not that many people
are surgeons left-handed or right-handed
and when we've got a lot of people though in the world who are manual workers,
either in metal or wood or something like that.
I know from my own experience that
when you're using, for example, power tools,
quite often the safety devices
and the control of speed and power are set up for a right-hander,
which automatically puts me at a disadvantage.
Is that just me or did you find that more generally?
Marietta: Indeed that most tools are designed for right-handers,
and this is actually also an implicit assumption
in the literature on handedness and hand injuries,
the fact that workstations tend to be designed for right-handers.
However, I must say that this assumption
has been made without proper empirical observations.
This is why a study published by McKinsey and Peters in 2000
in the Journal of Safety Research is very interesting.
What McKinsey and Peters did
is that they surveyed not people but workstations
to see whether they're designed to favor right-handers.
They focused specifically on workstations in the metal manufacturing industry
that require the collaboration of both hands,
and they measured different things.
For example, the number of times the right or left hand was engaged
in seven movement categories,
for example, grasping or turning or applying pressure.
Also, they measured whether emergency controls
found on those workstations were operated by the left or the right hand.
What the study found was that
individual machines do favor one hand over the other,
but overall there was no clear bias favoring the left or the right hand
when operating a machine.
Let me remind you that we're talking specifically about
the metal manufacturing industry here.
However, emergency controls very strongly favored the right hand.
At least in the metal manufacturing industry,
there seems to be no disadvantage to the left-handers
when it comes to operating machines.
Still, left-handers might be at a disadvantage
assuming that they're slower in operating the emergency control with the right-
Sophy: That's very serious. That's pretty serious-
Marietta: -than with their preferred hand. Yes.
Sophy: -because losing a little bit of speed
on operating an emergency control
could have rather drastic consequences.
I did see somewhere
that there are more occupational safety and health accidents
for left-handed workers.
Did you find any data or any evidence to support or disprove that?
Marietta: That takes me to the next occupational category
I would like to talk about,
and this is woodworkers who operate power saws.
In this case,
we know that the power saws do not come in left-handed versions
and they are among the most dangerous tools.
Just to put this in perspective, in wood processing work
there are hand injuries,
and these form something like 37% of all injuries,
but when it comes to saws, hand injuries are 67% of all injuries.
Left-handers are 10 times more likely to sustain a major injury
compared to right-handers when they operate.
Sophy: 10 times.
Because they cannot really see where they're cutting.
Sophy: Right. That's a bit hair-raising.
What about office workers?
Not all of us work with power tools.
A lot of us work in offices,
but there I find, I know, for example,
that when you sit in a lecture desk or in an office desk,
often the desk are set up for right-handed people.
Did you find that that makes a difference in terms of stress
or efficiency or anything like that?
Marietta: It was surprising, but we don't really have published data
on office workers.
We only have a survey performed by CB Library,
which is a UK job website.
This showed that
employers are not really into the habit of asking their new staff members
if they're left-handed.
Once if you have not identified someone as being left-handed,
clearly, you cannot give them the right equipment to work with.
This survey also showed that
only a quarter of businesses provide left-handers
with specialist computer equipment.
For example, a left-handed mouse.
Another interesting finding was that
workers who are ambidextrous,
they say that they would like the freedom to choose
between left or right-handed equipment.
In the case of office workers,
the issue is not so much major injury
but finding the right tools to be productive.
Also feeling valued
and having your differences recognized and respected.
It's more a matter of convenience, of comfort,
of feeling like a member of the team, rather than anything else.
Sophy: Yes. Because it's not that difficult to provide, for example,
left-handed scissors or special computer mouses
or things like that.
Even left-handed rulers.
There are a lot of little things that can make one's work a lot easier.
Marietta: They're inexpensive as well.
Sophy: Yes. One final question that I have to address is,
and it may be an urban myth,
an idea that left-handers are better at things
which are creative
and involve problem-solving, that kind of stuff.
Did you find any evidence for that?
Marietta: That's another good question.
Here we have a number of published studies,
but findings are mixed.
Some studies have shown that this is the case,
others have shown that this is not the case,
so we don't have a clear answer yet.
My understanding of the literature is that
it probably is not the case
when it comes to left-handedness at least.
When it comes to mixed-handers,
then things might be different,
but still, we need more data to come in,
so this is not something that I can answer
with any degree of certainty.
The only thing that I can answer,
on a positive note, is that
maybe creativity is not associated with being left or mixed or right-handed,
but certainly, we can train ourselves to be more creative
whichever handedness we have.
Sophy: You mean to say I'm not innately more creative
than my rightie colleagues?
Marietta: Yes. I'm answering that, we don't really know.
Sophy: That's a little bit depressing.
I might be, I might be more creative.
Dr. Marietta Papadatou-Pastou, thank you so much
for telling us about your survey.
On International Left-Handers Day, let's hear it for left-handed scissors,
left-handed can openers,
left-handed potato peelers, particularly garden secateurs and desks.
To all you lefties, righties, and mixed-handers out there,
thank you very much for listening.
Join us again soon for another edition
of the ILO's Future of Work podcast.