This article is a highly speculative account of how our distant ancestors evolved the capacity for speech, together with the evolved capacities that would later be exapted to the behavioural functions of reading and writing.
I shall not pretend to be an infallible guide. Whenever you have a chance, take counsel with other travelers who have passed along the same route before. Compare their observations with mine and if this leads you to different conclusions, I shall certainly not be angry with you.Hendrik Willem Van Loon (1882-1944), Ancient Man, the Beginnings of Civilisations
Did our human ancestors actually 'invent' writing, or did spoken language and writing co-evolve?
Consider that in reading we can generally read the intent of a writer rather than be baulked by the writer's errors. Evolution has provided us with a largely subconscious error-correction mechanism which operates for both speech and writing.
I suggest that the human invention of writing 'out of thin air' is an impossibility. When writing first began to be used it must have had a firm underlying evolutionary basis in language, or some component of language, in order to be used as a system of visible tokens for language. I suggest that there must have been components of speech linked or linkable to eye-hand coordination without which writing could not have been developed.
Just Another Ape
Humans and other primates have much in common. In particular, we are vocalisers and tool users. At some time in the past when hominids diverged from other primates there was only one feature common to all hominids and lacking in other primates: all hominids stood upright. This, I suggest, is a crucial factor in the evolution of our use of language.
It has become unremarkable to suggest that evolution of the upright stance freed the hands to use tools. Nevertheless, I suggest that, since various primates use tools without the benefit of an upright stance, the upright stance must have evolved from other causes and then permitted a more skillful use of tools, especially with the evolution of opposable thumbs.
I suggest that upright stance co-evolved with ever more refined vocalising abilities. An upright stance would appear to allow a greater degree of voluntary control over breathing, perhaps related to swimming. Such breathing control is a pre-requisite for human-style, precisely-controlled, smooth vocalisation. Other refinements to the 'organs of speech', such as the descended larynx, may have become possible only after the upright posture was fully, or nearly fully evolved.
The Silent Ape
Before the evolution of language, there had to be a role for language to fill, an evolutionary advantage to be gained. On the reasonable assumption that our remote ancestors were hunters, an advantage suggests itself: cooperation in the hunt. However, a species that coordinates the hunt by making noises is going to be less successful than a species that can hunt in silence.
It appears reasonable to suppose that, in a sufficiently open area, first body language and then overt gestures could have evolved as a means of coordinating the hunt. Co-evolution of gestural abilities and of intelligence seems a plausible evolutionary path. Hunting requires an ability to find, track, and hunt down prey. A species which can out-think the prey has an evolutionary advantage. A sufficiently evolved gestural language, together with the necessary mental skills, would eventually allow a hunting species to plan ahead for the hunt as a social group.
A sufficiently evolved gestural language would eventually permit planning ahead in general, and the more precise allocation of tasks. This would enhance the survivability of a group whilst concurrently contributing to the evolution of greater cohesion. I suggest that the evolution of language was in parallel with the evolution of a social grouping based on a greater division of labour than occurs in animal societies generally: the precursor of human society.
Scratches in the sand
Once a facility evolved to interpret gestural signs as having ever more precise meaning, it would take little brain evolution to provide a capacity for the abstraction of signs. An ability to associate marks in the sand first with the creatures that made them, and then with gestures, would assist in planning a hunt.
I suggest that once the association of marks with gestures became possible, the groundwork was laid for an association of sounds with marks and gestures. I suggest that a gestural language, a language of marks, and a sonic language all co-evolved, with speech perhaps lagging behind. Later, in an environment where line-of-sight communication became difficult, spoken language would have had greater survival value. It could have rapidly overtaken gestural language in its utility and versatility, perhaps by exapting gestural brain functions to speech.
Through co-evolution, our distant ancestors could have evolved the capacity for speech, together with the capacities that would later be exapted to the functions of reading and writing. Our remote ancestors hunted using gestures during the hunt. This evolved to abstraction: gestures to plan the hunt, later accompanied by and even later replaceable by both marks in the sand and sounds. Later, the sounds and marks (sketches) came to be signs for objects, actions and finally, ideas.
It is highly unlikely that we may find the fossilised remains of marks deliberately made in the sand by an ancestor. However, it is not difficult to imagine an ancestor showing a child how to track an animal by making approximations of animal tracks and human footprints in the sand.
The 'drawing' skill would later be evidenced first in cave art, then in pottery and carvings, finally in recognisable visual abstractions of sounds, i.e. writing.
References / further reading:
Christophe Boesch, Cooperative Hunting Roles Among Tai Chimpanzees
Fragaszy et al, Wild Capuchin Monkeys (Cebus libidinosus) Use Anvils and Stone Pounding Tools
Bart de Boer, Articulator Constraints and the Descended Larynx
Riede T, Zuberbühler K., Pulse register phonation in Diana monkey alarm calls
[edit - added two more links]
University of St. Andrews, How gorilla gestures point to evolution of human language
University of St. Andrews, The Development of Spontaneous Gestures in Zoo-living Gorillas
Dr. C. George Boeree, Human Evolution
Dr. Dennis O'Neil, Primates
If you have enjoyed reading this, you may also enjoy New Hominid Discovered : Anoiapithecus brevirostris and other articles on language and linguistics in my blog: The Chatter Box.