The surprising origins of talking with your hands
Transcriber: Emma Gon
Reviewer: David DeRuwe
There is a secret love affair
that’s been going on your entire life,
and you might not be aware of it.
It’s a hidden romance
between your hands and your voice.
Glenn Gould is one
of my absolute favorite pianists.
What I’ve always loved
about his recordings
is that you can often
faintly hear his voice
singing the melody in the background,
sometimes even multiple melodies at once.
And it creates a feeling of his presence
and echoes the voice
in my own head following along.
Gould himself said
that the singing was unconscious
and that to reach the level
of performance he sought,
he couldn’t help but sing along.
And this anecdote is quite telling
of the very mysterious relationship
between hand and voice.
Throughout my research, I came across
many examples of this relationship
and possible hypotheses of its origin.
I’m a voice expert and a recent
PhD graduate from the MIT Media Lab,
and for the past 10 years,
I’ve researched what makes
a voice so rich and unique
and I build technologies to help
reach a higher level of understanding
of the voice in a holistic manner.
Among various previous projects,
I’ve worked on wearables
for singers to visualize their voice
and change their vocal posture,
apps based on the neurology of the inner
voice to help people who stutter,
devices that let you touch your voice
and become aware
of its physical vibrations,
technological intervention
in zoos to change
to enter cross-species dialogue,
and software that changes the way
you hear your own chewing sound
to affect your perception of taste.
And based on my research,
I’d like to share a story that illustrates
the importance of looking
at the voice holistically
and the insight that might come
from bridging different fields.
So there are many different examples
of this connection between hand and voice,
starting with dexterity,
the fine motor skill control
often referring to manual activities.
Each time you type
on a keyboard or handwrite a letter
or doodle on a piece of paper,
you are precisely synchronizing
the 60-plus muscles that you have
in both hands combined.
Fun fact - you actually don’t have
any muscles in your fingers;
finger joints are controlled
by muscles in the palm and forearm.
And now think of the 100-plus muscles
that you need to synchronize
each time you create a vocal sound.
Most professional pianists
and opera singers alike
know that to push
their musical craft to an art,
they need intense practice,
physical exercise, and muscle care.
But even most of us are very good,
even virtuosos, at the everyday
use of our hands and voice.
There’s really no other part of our body
that we can control so precisely,
But sometimes this control fails.
In Parkinson’s disease,
hands and other extremities
are some of the first
affected by the symptoms,
and yet, patients report that their
difficulties in controlling their voice
and being heard is one
of the most profound handicaps.
This parallel of control
between hand and voice
goes deeper than the eye can see.
In the brain, most of the motor commands
that you do are controlled
by the motor cortex,
and in there, every part
of your body is mapped
in an orderly manner to the brain tissue,
but instead of following
a spatial mapping from head to toe,
this mapping is a little bit
all over the place,
with more space allowed
for more precise control.
Not surprisingly, the control of hands
and the one for facial muscles,
voice, and lips occupy
most of the space in there.
But more interestingly,
they are located right next to each other.
Researchers have hypothesized
that this anatomical proximity
might be due to one important activity
that involves both hand
and mouth - eating.
And indeed, to feed themselves,
one of the most necessary
behaviors for survival,
early primates had to become master
of hand-mouth synchronization.
But this original proximity
might also shed some light
on some of our current use
of hand and voice.
We know that many ape species
have fine motor command of their hands,
but not of their voice.
They can delicately shell peanuts,
but seem to not be able
to articulate sound with much precision.
And one central theory
is that language might
have originated from hand gesture
and was only later transmitted
to the voice muscle.
One way this might have happened
is by some sort of contagion of movement,
a sympathetic subconscious transmission
of motion from hand muscle
to voice muscle.
And this theory was already
being treated by Darwin in 1782
when he observed and I quote,
“Children learning to write
often twist about their tongue
as their finger moves
in a ridiculous fashion,” end quote.
The theory of the gestural
vocal proto-language
is also supported by other
structural aspects in the brain,
one being, handedness.
Most humans have a dominant hand,
and in 90% of the cases,
it’s the right hand.
Also there’s still
argument amongst researchers;
it seems that a lot of species
also show handedness,
or should I say, “pawdedness.”
But in most research
on cats, dogs, and primates,
we see that individuals are more equally
divided between right dominance,
hand dominance, and ambidextrous.
So it seems that humans
are one of the rare species
to have such a drastic
incidence of right dominance.
And as a brain is contralateral,
meaning that each half
of your body is controlled
by the opposite hemisphere in the brain,
it means that most humans
are left-cerebral dominant
for hand control,
and that’s another similarity
with the voice,
as not only most language areas
in the brain of humans
are generally located
in the left hemisphere,
but we also see that in a lot of species
who have left-cerebral
dominance for vocalization.
And a theory here
is that hand dominance might
have come from the voice to the hand.
So to summarize,
language went from hand to voice
and lateral dominance from voice to hand.
Moving away from the brain,
the human larynx or voice box
also keeps all the cues
of this co-evolution
between upper limbs and the voice
in the presence of what we call
the vestibular folds.
So those folds look
like a little pair of curtains
in front of your vocal cords,
and you can think about it
as the vocal cord of a fragile little door
that can be damaged
and can’t take too much pressure.
But the vocal cords are a much stronger
gate that allows us to maintain pressure
of air inside or outside
and maintain more core stability.
And they exist in many other species.
In the salamander,
those vestibular folds are necessary
to resist the water pressure
that would otherwise drown them.
In chimpanzees, they help
with preemption and holding onto branches.
And in humans, they’re very useful
for weightlifters during breath pause,
and also surprisingly, babies.
When babies are born
and until three months of age,
they’re able to hold
their entire body weight with one fist,
and that’s thanks
to those vestibular folds.
When singers apply
too much pressure to their vocal cord,
they can make those
folds’ vocal cord vibrate
and that creates a deep,
rich rumbling sound
that we find in Tuvan throat singing
and also the songs of Louis Armstrong.
But for most of us, this hidden voice
relationship is most often observed
when people talk with their hands.
Whether a learned habit
to be a more efficient speaker
or a cultural trait like in many
Mediterranean languages,
it’s been shown to enhance communication.
And indeed, you can learn
a whole series of tricks
to be a more likeable speaker:
palms up for request,
clenched fist for firm commitment,
but beware of hidden hand or hand on hip
that makes you look less
trustworthy or overconfident.
(Laughter)
In a different context,
voice actors often guide themselves
with hand gestures to guide their tone.
So if you’re looking
for the right tone or prosody,
you can guide yourself with your hands
and let your voice follow your body.
Be your own conductor.
Hand gestures are also associated
with better speaking in children
by improving access to memories.
And this is particularly
true in young girls
who acquire language earlier than boys.
But also in adults, hand gestures
are linked with a good mnemonic.
So next time you can’t find the word,
try moving your hand.
Maybe a hand puppet might help.
(Laughter)
I hope this tour
of various hand-voice phenomena
has shed some light on the many strings
that tie your hand and your voice
in such a tight relationship.
What stands out to me
is that although this union touches
many aspects of communication -
muscle motor command, memory, brain -
it seems to transcend
verbal content and language.
The hands give us a sense
of the richness of the voice beyond words.
This bond also reflects
on the importance of muscle action
as a deep root of the voice
and maybe also its internalization.
If you ask a person deaf from birth
what their inner voice feels like,
they might describe something akin
to a pair of hands moving in a void.
This ethereal image reflects
the immateriality of the voice
as being able to exist
in many shapes and forms.
So what can we learn from this?
Your voice is an action.
It is how you touch people.
It can be a punch or a caress.
It can be a piece of art or a forgery.
It can be a hug or a struggle.
It can be a manipulation or an invitation.
Thank you very much.
(Applause) (Cheers)