Cesar
speaks in Dawn of the Planet of the Apes.
This is
amazing
and impossible. But what may be worse – he’s a
face
painter! He would fit in at a hockey game or a
Seinfeld
episode.
|
Is it possible that
they could learn speech within one decade? Are apes just not trying
right now? The grand question would be, why is it that humans are the only
animals that use spoken language to communicate?
To
begin to answer our questions, one first must decide what a language is. Linguists have four criteria for
sounds to be a language. One, each vocalization has a certain order – the short
"i" sound always precedes the "en" sound in the word “in.”
Second, there must be an order to vocalizations – this is syntax. Third, the
vocalizations cannot be tied to or defined by a specific emotional state – you
can yell the word “Hey,” either to let someone know a bus is driving at them, or
to say hi a friend you meet for coffee. And fourth, novel vocalizations are
understood – you can say something that has never been said before, but those
people listening to you will understand its meaning.
If sounds follow
those four rules, then they’re an oral language. So humans have spoken language
and other animals don't - although the majority of people don’t use the gift very
well. But the question remains, why are humans so much better at making sounds
and language than primates? We share 98% of our genes with chimpanzees, but
they can make only three dozen or so vocalizations. Humans can make hundreds of
different sounds – every noise required for every language on Earth. Where did
we separate from apes in terms of vocalization?
Current hypotheses
focus on two areas; brain molecular biology and body anatomy. Let’s focus
on the anatomy – we can make more vocalizations because of how our throats and
chests have evolved.
The tongue is a
muscle, and ours goes further back in our throat as compared to that of apes.
Theirs is housed completely within their mouth, but we can change the shape of our voice box by using our tongue. You
can stick out your tongue and move it side to side and feel your Adam’s apple
move. Your adam's apple is NOT the same thing as your hyoid bone; the adam's
apple is the laryngeal prominence associated with your voice box, but you can
see that moving your tongue can modulate the vocal folds.
The other
characteristic of the tongue that makes a difference is that it is our most
sensitive touch appendage. We can make small and discrete moves with the
tongue, and sense where it is in relation to our teeth and cheeks. This is
another reason we can make so many different sounds, and is also why babies put
everything in their mouths.
Another anatomical difference is that humans have a
free-floating hyoid bone; it is the only bone in the human body that is not
anchored to another bone. By attaching to the pharyngeal and tongue muscles,
our hyoid helps us to make more than hoots and grunts. While apes
do have a hyoid bone, it is not located as deep in their throat as is ours. In
fact, infant (human) larynx and hyoid bone anatomy looks a lot like ape anatomy,
but as we grow, our voice box and hyoid bone descend in our throat, while those
of the apes do not. This is one reason it takes babies a while to learn to
speak, muscle tone being another.
The Foxp2 protein is
involved in vocalization and in understanding language. In songbirds with a
mutated foxp2, their song is incomplete and inaccurate. In humans, defects in
foxp2 activity lead to severe language impairments in both speaking and in
understanding. Two small mutations in the human foxp2 are much of what separates our language ability from that of the apes.
A 2014 commentary
takes the idea of bird song further, hypothesizing that human speech evolution
was a reawakening of avian constructs in the basal ganglia of the brain, with
the “tinkering” afforded by time, pressure, and mutation.
If not, then maybe he understands our language, but he won’t be speaking it. And what about his cohorts? They speak too, although nobody played molecular hanky panky with them. And all this takes place within the lives of this single generation! The 1968 movie had time on its side, the evolution through generations was at least plausible. (but why did they speak English?)
For the new movie, it isn't evolution they so, it isn’t even evolution on steroids. The talking apes
toss out Darwin completely and smell of Lamarckian evolution meets the Hulk
(see this post). Come on Hollywood, give us a little credit – if you want us to
buy in to a world we recognize, then stick to the natural laws we know.
Contributed by Mark E. Lasbury, MS, MSEd, PhD
As Many Exceptions As Rules
Ackermann H, Hage SR, & Ziegler W (2014). Brain mechanisms of acoustic communication in humans and nonhuman primates: An evolutionary perspective. The Behavioral and brain sciences, 1-84 PMID: 24827156
Contributed by Mark E. Lasbury, MS, MSEd, PhD
As Many Exceptions As Rules
Ackermann H, Hage SR, & Ziegler W (2014). Brain mechanisms of acoustic communication in humans and nonhuman primates: An evolutionary perspective. The Behavioral and brain sciences, 1-84 PMID: 24827156