'EARLY-BLOOMER' VERSUS 'LATE-BLOOMER' THEORIES
Commentary on Bichakjian on Language-Complexity
Thomas Suddendorf
School of Psychology
University of Queensland
Brisbane, Qld 4071
Australia
t.suddendorf@psy.uq.edu.au
ABSTRACT: By investigating historic changes in complexity
Bichakjian (1999) tries to convince linguists that languages
evolve. Here, I wish to add a reason why speculation about the very
origin of language may be a fruitful endeavour. The significance of
the question, and increasing archaeological evidence, has resulted
in an avalanche of recent proposals. These accounts can be divided
into two broad categories; those that advocate either early or late
emergence. The "late-bloomer" theories face the likelihood of being
disproved by mounting evidence, yet it is precisely for this reason
that theories of the evolution of language might gain
respectability within the realms of scientific inquiry.
1. In 1866, the Paris Societe de Linguistique banned any debate about
the evolutionary origins of language (Figure 1.). Yet, in recent years
theorising about the natural history of human symbolic or
representational capacities has increased dramatically. Psychologists
and philosophers have proposed diverse accounts on the phylogeny of the
human representational mind (e.g., Bickerton, 1995; Corballis, 1991;
Corballis & Lea, 1999; Deacon, 1996; Dennett, 1995; Donald, 1991; Lock
& Peters, 1996; Noble & Davidson, 1996; Pinker, 1994; Suddendorf &
Corballis, 1997; Suddendorf, 1999). The theories differ in many
respects (e.g., emphasis on cognitive, social or ecological factors),
but for the present purpose I want to divide them into two broad
categories: 'early-bloomers' and 'late-bloomers'.
Figure 1. Paris Linguistic Society Ban on Language-Origins Papers
(1866).
ftp://www.cogsci.soton.ac.uk/pub/psycoloquy/1999.volume.10/Pictures/sud.htm
2. The early-bloomer theories argue that language began to develop
early in hominid evolution, perhaps as early as 5 million years ago
(Pinker, 1994). Some 2 million years ago, with Homo habilis and Homo
erectus, there are the first indications, such as stone tools and a
marked increase in cranial capacity, which hint at new cognitive
capacities. Furthermore, there is some evidence for the existence of a
human-like Brocas area (Holloway, 1996). Moderate versions of this
stance hold that representational skills developed gradually over a
long stretch of time. These accounts are supported by the fact that
there was a progressive increase in brain size over the last 2 million
years. Donald (1991) and Corballis (1991), for example, argue that Homo
erectus might already have had some basic symbolic capacities (mimetic
culture) which were progressively exploited in gestural communication.
Early gestural communication may then have gradually developed from, as
Mike Corballis puts it, 'hand to mouth' leading to vocal language in
modern Homo sapiens by about 130,000 years ago. The anatomy of the
vocal apparatus of these early modern humans suggests that they were
capable of speech (Lieberman, 1998). What else would have selected for
the modern morphology (a dropped larynx, for example, raises the
likelihood of choking)?
3. Yet, there are many proponents of late-bloomer theories who argue
that human language evolved rather abruptly in only very recent times.
Bickerton (1995), for example, suggests that a single mutation gave
sudden rise to syntax. Nobel and Davidson (1996) also argue for a
recent advent of language, seeing this as caused not by biological
evolution (mutation) but through the accumulating effects of culture.
An increased understanding that traces (e.g., footprints) stand for
other objects might have gradually led to the conscious use of symbols.
While anatomically modern humans roamed the Earth about 130,000 years
ago, the first strong evidence that they used symbolic representations
(e.g., ornaments, figurines and paintings - 38,000 to 32,000 years old)
is the beginning of Palaeolithic art around 40,000 years ago (Bahn,
1996). The earliest incontrovertible evidence for the presence of
language, however, is of course only about 5,500 years old (i.e., the
first writings). The hiatus between the emergence of anatomically
modern humans and the first evidence for symbolic thought has been used
to support the claim that modern humans evolved language very recently
through social construction (Lock, 1999). Similar arguments have been
advanced for other human representational skills. Baron-Cohen (1999),
for example, claims that only with the artefacts emerging in the last
40,000 years do we have evidence for a representational theory of
mind.
4. It should be pointed out that there are different prospects for
late-bloomer and early-bloomer accounts of language evolution.
Regardless of the sophistication of each of the late-bloomer theories
and, indeed, regardless of whether they are closer to the truth than
the early-bloomer theories, only the late-bloomer theories can be, and
I may add are likely to be, disproved. For example, the finding of a
single clear artefact of symbolic representation confidently dated at,
say, 250,000 years ago would shatter the 40,000 year theories. One
contender for this position (the Berekhat Ram 'figurine') has already
been proposed (Marshack, 1997). However, no find could possibly falsify
an early-bloomer theory that, say, postulates that even Homo erectus
was capable of cave drawings. Absence of evidence is not evidence of
absence.
5. One of the main reasons why these theories have emerged in recent
years has been an increasing amount of archaeological evidence.
However, the crucial aspect of dating these finds is still very
difficult. Many theorists, including myself, unquestioningly took the
word of archaeologists, and treated the fossil record at reported face
value. However, I believe that we are in for a few surprises. Not that
I can foresee the future or that I have discovered a new way of
dating. Rather, some fossil dating is likely to make errors that
underestimate fossil dates, again to the disadvantage of late-bloomer
theories.
6. Most of the dating we find in our textbooks is based on the Carbon
14 method (14C). The radioactive isotope 14C is assumed to have been
present in a fixed ratio to 12C in the atmosphere. When an organism
dies it no longer absorbs 14C and the isotope decays at a constant rate
to 14N by beta-emission with a half-life of 5730 years. Calibrating
samples against tree rings of known age has improved the accuracy of
radiocarbon dating in terms of actual chronological age up to about
6000 years ago. However, the dating of older items becomes increasingly
unreliable and is ever more prone to error. After 40,000 years less
than one percent of the original 14C remains in the sample and
radiocarbon dating becomes nearly impossible.
7. The older the item the greater the chance that there is some form of
contamination. Anything would do: some root material, improper
handling, or some organic waste transported through underground water.
If there is any contamination with later organic matter it will make
the fossil appear to be younger than it actually is by introducing
fresh 14C. A 200,000 year-old object could thus erroneously be dated to
be 32,000 years old. Note, however, that in limestone caves, for
example, more ancient carbon can also be introduced making younger
samples appear older. Establishing the past is difficult and research
continues to deliver surprises [2]. Given that the extent of classic
radiocarbon dating is limited to 40,000 years and that most of the
early evidence for symbolic skill has been dated with this method at
around the end of its dating capacity, it would not be surprising if
better dating methods revealed some older dates. While the age of other
items may have been overestimated, these errors would not pose a threat
to either late or early-bloomer theories. But a few items that prove to
be older than what is currently believed would pose difficulties to the
late-bloomer theories.
8. Indeed, there is already some such evidence emerging. Aborigines
were thought to have reached Australia some 40,000 years ago. The
argument was based on a number of fossil datings pointing to between
32,000 and 38,000 years ago for the oldest finds. Recently, Thorne
(1999) re-examined one of these fossils: Mungo 3, the skeleton of a
male buried in a grave with red ochre. 14C dating put its age at
between 28,000 and 32,000 years old. Thorne used three different
methods of dating: Optically stimulated luminescence, electron spin
resonance, and uranium decay. All three measures converged on a date
between 61,000 and 62,000 years. While this date is still
controversial, it could help explain the extinction of megafauna on the
Australian continent around that time.
9. If this date holds up, it will have a profound impact on the most
extreme late-bloomer theories. Those who argued for a 40,000-year date
for the evolution of language will have to explain how this universal
human skill reached isolated Australia. Aborigines are fully modern
humans with very sophisticated languages. The evolution of language
would therefore have to have happened well before they arrived down
under (unless one was to propose parallel convergent evolution or
cultural transmission from as yet unidentified visitors). In other
words, the latest date for late-bloomer theories would have to be
somewhere around 70,000 years ago. And there is a good chance that this
date will be pushed back further.
10. In contrast to the settlement of Australia, modern humans seem to
have reached Europe only around 40,000 years ago (Stringer, 1996). They
displaced the local Neanderthal population 35,000 to 30,000 years ago
and began to leave the legacy of symbolic artefacts that were part of
what came to be known as the Palaeolithic revolution. One new
technology associated with this advance is the use of bone for tools.
Recently, however, Yellen, Brooks, Cornelissen, Mehlman & Stewart
(1995) reported evidence for a much earlier bone industry. Their finds
in the former Zaire (Republic of Congo) revealed dates from about
90,000 years ago. Our understanding of prehistory is plagued not only
by the difficulty of dating, but also by a bias towards studying the
European past. If it is true that modern humans reached Europe only
40,000 years ago, Africa and Asia would be more obvious places to look
for early symbolic evidence.
11. The early-bloomer theories will never be surprised by a new find of
a Venus figurine that is even younger, but late-bloomer theories will
always be threatened by new evidence pushing back the time when
something first emerged. Naturally, those theories that argue for the
most recent dates are the first to fall victim to such new evidence.
More moderate late-bloomer theorists who see transitions at around
100,000 or even 150,000 years ago can feel slightly more secure. But
the push into the past continues. Here is one more example.
12. The oldest evidence for hunting with spears used to be about
125,000 years old (a thrusting spear recovered from between the ribs of
an elephant), supporting a late-bloomer idea that big game hunting
first emerged with modern Homo sapiens. Yet, Thieme (1997) recently
excavated wooden throwing spears in between deposits of the Elsterian
and Saalian glaciations. The well-studied sedimentary sequence at this
site suggests that the spears are about 400,000 years old. The spears
were found in association with 10 butchered horses, suggesting that
there was coordinated and planned big game hunting well before modern
Homo sapiens. Again, the boundary can be pushed in only one direction.
The question is how far back.
13. This sounds like bad news for all those cherished late-bloomer
theories. However, it is precisely because they are likely to be
falsified that they represent good Popperian science. It may be exactly
for this reason that we might choose to disregard the Socite de
Linguistiques ban.
FOOTNOTES
[1] Bichakjian 19999 argues that the linguistic invention of tense
might have freed our minds from the constraints of the present. In
Suddendorf and Corballis (1997) we argue, to the contrary, that mental
time travel, the ability to generate the mental experience of past and
future, probably preceded the ability to communicate it. The causal
relationship between the evolution of these skills is by no means
clear. After all, both, language and mental time travel appear to be
based on similar attributional, representational, dissociative and
generative skills (Suddendorf & Corballis, 1997).
[2] It is worth mentioning here a very recent blow to one of the most
influential methods of reconstruction of our common ancestry (i.e.,
using sequence markers on mitochondrial DNA to trace maternal
ancestry). Awadella, Eyre-Walker and Maynard-Smith (1999) have shown
that mitochondrial DNA does recombine! Thus, reconstructions pointing
to a common ancestor of all humans (a mitochondrial Eve) living less
than 200,000 years ago (e.g., Waddell & Penny, 1996) are brought into
question. Our common ancestor might well be twice as old (John Maynard
Smith, personal communication, 02.12.1999).
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