James Hurford, “The Origins
of Meaning”.
Reviewed by Derek Bickerton
James Hurford has been working on the
evolution of language for the last two decades.
His first paper on this topic appeared in the 1980s (Hurford 1989),
antedating the work of Pinker, myself, and just about anyone else currently
active in the field. He has written
numerous stimulating and insightful, if often controversial, papers and has
co-edited two collections of conference proceedings (Hurford et al. 1998,
Knight et al. 2000). However, until now
he has not attempted any full-length treatment of the subject, so the current
volume has aroused considerable interest and high expectations.
This volume is the first of two on
language evolution; the second, on formal and structural aspects of language,
will be published at a later date. The
present volume devotes itself entirely to the question of how the formal units
of language came into existence, and how obstacles to using such units communicatively
were overcome. The book is divided into
two parts, “Meaning before communication” and “Communication: what and
why?” These parts, each of which
contains five chapters, are of almost identical length, accurately reflecting a
balance between the cognitive developments that led up to language and the ways
in which, and purposes for which, that cognition was expressed in interactive
ways.
Chapter 1 performs the
ground-breaking operation, vital in any interdisciplinary inquiry, of removing
ambiguities from expressions that may have different meanings in different
disciplines, or between lay and expert users: “reference”, “intention”, and of
course “concept” are just some of these.
In the second chapter, Hurford picks up the notion of “concept”, sticking
closely (as he does almost throughout) to the literature on animal
experimentation, to discuss properties that may form necessary pre-requisites
for a semantics adequate to support language, such as transitive inference,
object permanence, animate-inanimate distinctions and cross-modal links. While he overtly rejects any kind of
cognitive scala naturae leading
ineluctably to humans, it is not easy to see how such a ladder would differ greatly
from his stated belief that “our animal ancestors approached modern human
cognition to various degrees” (20).
In Chapter 3, he deals with
the evolution of episodic memory, essential in humans first for the
organization of experience and second for retailing those experiences with the
help of a syntax based upon argument structure. He analyzes behavior that suggests the
presence of some form of episodic memory in animals, from scrub-jays caching
food to rats interrupted in searching mazes, and appeals to Kant’s
philosophical notions to support a clear distinction between semantic and
episodic memory, likening their content to, respectively, Kant’s “analytic” and
“synthetic” propositions. He sees the
ability to distinguish between the two forms of memory as being shared by animals
as disparate as rats, jays and chimpanzees, and as an essential pre-adaptation
for language.
Chapter 4 returns to the
theme of an earlier article (Hurford 2003) in which Hurford hypothesized that
the dorsal and ventral pathways in the brain are what underlie the most basic
distinction in formal logic, that between predicates and arguments—the dorsal
pathway (the “where” channel) merely predicating the existence and location of
something, the ventral pathway (the “what” channel) analyzing sensory data more
finely to determine what that something is.
Since these pathways are fully operative in many animals, he concludes
that the latter are able to process predicate-argument structures. Since he
regards the logical predicate/argument distinction as prior to, and in some
sense underlying, the most basic distinction in linguistics (that between
subject and predicate), he sees a capacity to make the logical distinction as a
pre-adaptation for basic syntax. To put
it more simply, animals can, potentially at least, form mental propositions
In the final and fifth
chapter of Part 1, and the only one that does not draw extensively on the
psychological literature, Hurford seeks to “capture the private mental
representations of animals at an evolutionary stage just prior to the emergence
of public language” (125)—in other words, to show how the mental propositions
of Chapter 4 might be represented in animal brains. Since propositions normally involve ascribing
some behavior (a predicate, an action or event) to some entity (a subject, an
entity of some kind), he then faces the difficult task of determining how, in
terms of mental operations, animals might have gone about making distinctions
that are not obvious from the stream of raw sensory data that constitutes the
input to cognitive processes—the “blooming, buzzing confusion” that William
James described. In analyzing a scene,
the “global” and “local” distinctions derived from dorsal and ventral pathways
here furnish the basis of a novel formalism for expressing what, according to
Hurford, animals can see and know but cannot yet express.
Although he never uses the
expression “language of thought”, the notion of something similar to this seems
implicit in much of what Hurford writes in this and other chapters. He cites Fodor approvingly, and concludes the
first half of the book with the following advice to seekers after the
pre-requisites for language: “[S]tart your thinking…by imagining yourself in a
non-linguistic state, but otherwise
cognitively pretty much as you are” (164, emphasis added). Summarizing that first half in a final
sentence, he says, “We’ve seen what [animals] know; in Part II…we’ll examine
why they don’t tell.”
The second part of the book
kicks off with a chapter (#6) on the origins of communicative behavior. Hurford notes that “communicative acts
evolved out of non-communicative acts” (169) and that common to all of them
should be some benefit to the actor. He
sees early communication as merely dyadic, involving a sender and a receiver
but no third party, no referent that is meant to focus the attention of both,
and hypothesizes that more complex forms of communication developed out of,
rather than alongside, this more primitive form. The remainder of the chapter examines dyadic
communication in other species, the factors that promote it, and the extent (a
limited one, he admits) to which one could say that signals used by animals
were learned rather than innately specified,
In Chapter 7, Hurford turns
to an examination of how objective reference might have entered animal communication
systems. He discusses the mixed evidence
with regard to what is perhaps the most basic referential act—pointing—in
animals, and continues with a discussion of types of animals signal (food calls
and alarm calls) that contain what has been termed “functional reference”. He concludes that at least some signals, for
example the alarm calls of vervets (who must be tired by now of appearing in so
many language-evolution books) not only refer but denote, and like words have a
particular class as their extension.
Chapter 8 focuses on
motivation. To communicate information
to others seems to run counter to the self-interest of the informant, since it
is the receiver not the sender who principally benefits from such acts; for
this reason, language constitutes a long-standing puzzle for evolutionary
biologists, Hurford surveys some of the
major attempts at solving that puzzle, including theories of kin selection,
inclusive fitness and reciprocal altruism, as well as theories that try to
relate language to conspicuous display such as Zahavi’s handicap principle and
Miller’s sexual selection scenario.
Since none of these attempts seems to solve all the motivational
problems, he then gives qualified approval to the notion that here the group
rather than the individual may be the unit of selection. Groups where members communicate more with
one another collect a greater store of useful information than groups where
they do so to a lesser extent; the former should therefore out-compete the
latter under most circumstances.
However, such communicative groups
must first establish high levels of cooperativeness and mutual trust; words are
cheap and cheaters have much to gain.
Chapter 9 suggests how such levels
might be obtained; one pre-requisite is some sort of theory of mind, an ability
to perceive the intentions of others, and to know that these are not necessarily
the same as one’s own. Co-operation
depends on shared intentions, and Hurford endorses the claim of a recent
article (Tomasello et al. 2005) that shared intentionality necessarily preceded
language. As for mutual trust, he notes
some experiments with the neuro-peptide oxytocin, raised levels of which may
have provided the level of trust necessary to offset the cheapness of words. The tenth and final chapter, a mere three
pages, briefly summarizes his view that the cognitive and communicative
capacities of great apes had already reached a stage of imminent
language-readiness, and concludes with a capsule summary of the companion
volume that will detail the “cascade of consequences” (333) following the
“breakthrough” into language.
As the foregoing suggests,
Hurford brings to his task an almost encyclopedic knowledge of the literature
in a half-dozen fields. This knowledge
is displayed in a superbly-organized argument into which hundreds of disparate
pieces of information are neatly slotted, giving rise to a smoothly-flowing and
cohesive whole. Only rarely does his
erudition lead him into superfluous detours: his occasional nitpicking to
satisfy philosophers, or the discussion of “simultanagnosia” on pages
107-109. For the most part, the reader
is swept along effortlessly, despite the inevitable density and complexity of
much of the material. For a work aimed
both at experts and educated laypersons, his tone is pitch-perfect; he never
condescends to nor patronizes the reader, nor does he oversimplify complex
material, yet he makes difficult ideas easy to digest and even, quite often,
entertaining. He balances opposing
arguments fairly, yet seldom equivocates or fails to indicate where his own
sympathies lie. For once, book-jacket
encomia—“this major intellectual endeavor,” “the major publication dealing with
language evolution to date”—do not seem over-strained.
I sincerely wish it were
possible to close my review on this note.
I genuinely admire what Hurford has done here, and doubt whether anyone
else in the field could have synthesized so much information in so palatable
and user-friendly a manner. Yet I would
be remiss in my duty if I stopped there.
Precisely because the book is so good, it succeeds in concentrating and
focusing as never before an approach to language evolution that is very widely
shared--a view some aspects of which I myself have shared--but one that over
the last few years I have come to regard as an obstacle rather than an aid in
the search for the evolutionary origins of language. What follows should therefore be regarded not
so much as criticism of Hurford and his book as criticism of the tradition that
it represents. Indeed, I am in Hurford’s
debt, since the clarity and thoroughness of his work has helped to clarify my
own thinking on the vitally important issues the book raises.
Hurford mentions two or three
times—unlike many writers in the field, he doesn’t hide things—that the fact
that humans alone, but no other species, not even those closest to us, have acquired
language poses a serious problem for explanations of how language evolved. He frankly admits he has no solution to this
problem, but since nobody has ever even suggested one (and most people don’t seem
to recognize the problem) he then drops the subject. At the same time, although he makes
occasional disclaimers (“We will also see the still large gap that exists
between us and other species,” p. 2), his statement (cited above) that the
primates who pioneered language were “cognitively pretty much as you are”, plus
his view that “animal concepts provide a foundation for the meaning of words”
(19), suggest that he regards the cognitive capacities of other great apes as
little inferior to those of humans. The
only thing he doesn’t realize is the strange place that the conjunction of
these two lines of thinking leads to.
In his Ulyssean voyage across
the tangled landscapes and manifold perils of the field, Hurford must, sooner
or later, meet with a Scylla and a Charybdis:
Scylla: the lower you rate the cognitive
capacities of apes, the harder it
becomes to explain how we got
language.
Charybdis:
the higher you rate the cognitive capacities of apes, the
harder it becomes to explain
why they didn’t get language.
It was possible, with the
original Scylla and Charybdis, to somehow navigate between them. With this pair, it isn’t. Evade one and you are trapped by the other. Maybe, instead of trying to go between them,
you must seek out some entirely different path.
Hurford is very much aware of
Scylla, indeed he describes it quite explicitly: “If concepts only appear with
language, the origin of language itself is that much more of a mystery”
(10). So let’s look a little more
closely at concepts, but first let’s put them in a broader framework.
Hurford’s book appeared,
unfortunately, too late to include reference to a seminal but sure-to-be-controversial
article (Penn, Holyoak & Povinelli, in press) that takes a diametrically
opposite view on the cognitive capacities of apes. Citing many of the same sources Hurford cites,
the authors re-analyze the findings of these, and find a massive discontinuity
between ape and human forms of cognition; in particular, apes and other
non-human species lack the ability to perceive higher-order relationships such
as transitive inference and hierarchical structuring. But equally compelling, and quite uncontroversial,
is the point from which their article starts: “Human animals—and no other—build
fires and wheels, diagnose each others’ illnesses, communicate using symbols,
navigate with maps, risk their lives for ideals, collaborate with each other,
explain their world in terms of hypothetical causes, punish strangers for
breaking rules, imagine impossible scenarios, and teach each other how to do
all of the above” (p. 1). This list is a
random selection from one that could be multiplied a millionfold. True, many of the things in that longer list
require language, but many do not; representational drawing and tap-dancing are
examples, as is the invention of nooses, deadfalls and spiked pits for catching
the colobus monkeys chimpanzees are so fond of snacking on. If apes are “cognitively pretty much as [we]
are”, why don’t they do ANY of these things?
One possibility is that we
have concepts but they don’t. Since
there are so many definitions of concept around, let me make clear what I mean:
on the analogy of “news you can use”, I mean mental representations, formed
from neurons and their connections, that bear some kind of referential
relationship (we needn’t be too specific here about exactly what) to entities
and events in the real world, but (and this is the really important point) can
be concatenated with one another and purposely manipulated to produce novel
structures of thought. What animals have
in their place is “news you can’t use”—categories, rather than concepts, that
come together in animal minds only when triggered by some external
circumstance; otherwise, they will only appear sporadically in random brain
activity, and cannot be joined or used voluntarily for computation in the
absence of stimuli. This distinction
would have a purely physical basis.
Animal categories would
consist of separate loci, in the visual, auditory etc, areas of the brain,
where, for example, the sounds, smells and appearances that characterize, say,
a leopard would be separately stored, but there would be no locus in the brain
where all these representations came together—where they linked to a single,
all-embracing representation of “leopard”.
Human concepts would be based on a similar set of distributed
representations, but these would on addition be linked with just such a central
locus, which could be voluntarily activated without necessarily evoking all or
any of the partial, particular representations, and would be linked with
similar central loci. Such loci would
often, but not necessarily always, be tightly linked to representations of their
corresponding words. This is NOT a claim
that we can’t think about something if we don’t have a word for it; words were
probably the means by which the first of such conceptual loci were set up, but
we obviously can think about things without using words and about things we
have no words for. The point is that,
however they were originally formed, we would have permanently accessible
instantiations of abstract class concepts while non-humans would have scattered
representations of physical properties that could be brought together only by
external stimuli. Note that the
empirical status of this category/concept distinction can in principle (and
perhaps already in practice) be tested by means of modern brain-imaging
techniques.
Hurford, perhaps wisely in
his case, hedges his bets: “My choice of the terms ‘category’ and ‘concept’
allows the possibility (indeed the probability) that these mental entities are
fuzzy” (17). However, the distinction
made above is not fuzzy, and the distinctions between the things apes
spontaneously do and the things humans spontaneously do (in terms of the Penn
et al. list, above) is not fuzzy either.
The idea that these two discontinuities (sharp ones, no matter how hard
we try to blunt them) are linked—indeed, that the behavioral discontinuity is a
direct result of the representational discontinuity--deserves, at the very
least, closer scrutiny.
This distinction between
being able to perform mental computations only when external stimuli are
present and being able to perform them voluntarily in the absence of such stimuli—what
I loosely described as the distinction between “on-line” and “off-line”
thinking (Bickerton 1995)—becomes crucial in Chapter 3, where the outputs of
dorsal and ventral streams are characterized as combining to produce
proto-propositions. From Hurford’s viewpoint,
if an animal can compute, from sensory input, “X exists” and “X is a Y”, then
it is ready to acquire linguistic labels for X and Y and (once it overcomes the
purely communicative problems set forth in Part II) deploy them in some form of
language. (Just exactly what kind of
language, paleo- or proto- or the real McCoy, Hurford’s second volume will
presumably clarify.)
But we’re talking apples and
oranges here. Given the distinction between
categories and concepts described above, the fact that an animal reacts to
certain types of external stimuli in ways that can be compared with the
components of propositions in no way guarantees, or even implies, that those proto-propositions
then take on a mental life of their own, become subject to voluntary control,
and (once words are available) can without more ado be brought forth in
linguistic dress. Hurford is so
convinced that the “first propositions, then language” position is correct that
he never seriously considers the “first language, then propositions”
possibility. He mentions niche
construction theory, but only in passing.
He should perhaps consider some of its implications; if, as the theory
suggests, a major driving force in evolution is a feedback process between what
animals do (at first with very limited genetic equipment for it) and the
genetic variations that their activities select, the second possibility (or at
least some kind of beneficent spiral) begins to look the more plausible of the
two.
Wherever animal cognition is
concerned, Hurford always gives animals the benefit of any doubt there is. Nowhere is this more evident than in his
discussion of vervet alarm calls. Maybe
it’s just his wording, but to me the following passage seems almost to suggest that
global concepts are epistemologically prior to distributed, sensory-based
representations:”[W]e can expect the vervet monkey to have, not only leopardvervet
but also leopard-motionvervet
and leopard-smellvervet. None of these prelinguistic predicates is
necessarily simply translatable into the words of any human language, but leopardvervet is pretty close
to an English speaker’s leopard”
(97, emphasis added). Little evidence is
offered for the latter claim. Hurford
grants that English speakers can think of leopards in their absence, but
extends a similar privilege to vervets: “[W]e have seen that rats probably
dream of mazes, so might not a vervet dream of a leopard?” (ibid.). Possibly, but so what? Dreams are not subject to the dreamer’s
control, and even with regard to our own dreams, we don’t know whether these
trigger core concepts or merely the distributed representations on which categories
are based, so how could we know what semantic level is being tapped in animal
dreams?
One thing vervets (and other
non-humans) cannot do is communicate any information about past, future and
physically non-present leopards. It
seems likely that this inability merely reflects a similar inability to think about leopards in their absence,
and that both deficiencies are functions of the lack of any of the class
concepts that underlie human thought and language.
But to Hurford, monkeys’
alarm calls are as close to words as monkeys’ internal representations are to
human concepts, and bear the same (or at least
a comparable) relation to one another as human words and concepts do. He treats an experimental finding (that Diana
monkeys show less alarm on hearing an eagle’s shriek five minutes after an
eagle warning than on hearing a leopard’s cough five minutes after an eagle
warning) as evidence that the monkeys have maintained a focal concept of
“eagle” in mind and therefore are less startled when the same threat is
repeated than when a new one appears. He
does not consider simpler explanations; for instance, after an alarm call
monkeys will continue for some time to employ the appropriate strategy (“Scan
the sky, make sure you’re near cover” after an eagle call, “Scan at eye-level,
get near a tall tree” after a leopard call).
Having to suddenly switch strategies, or becoming unsure which strategy
to pursue, is far more alarming than simply having to focus the original
strategy.
The problems with alarm calls
are, however, merely symptoms of a much broader problem, which involves the relative
properties of animal signals and language.
For Hurford, language and animal signals fall under the same broad
umbrella: both involve “the vital illocutionary doing-things-to-each-other
property that is common to primate calls and all human utterances” (184). Well, yes, this is a property they do share,
but aren’t there some equally important ones that they don’t? As mentioned above, Hurford grants that
communicative acts arise out of non-communicative acts, which is certainly not
true of any of the units that compose language.
He does not pursue this issue far enough to ask what these original
non-communicative acts (or the present communicative ones, for that matter)
were for. What they were for, why they
were there at all, of course, was maximization of animals’ (inclusive) fitness;
postures that indicate subservience, for example, refined by natural selection
into stereotyped signals, save animals from being trapped into confrontations
where their procreative potential might be damaged or altogether
destroyed. Obviously such signals won’t
work unless they communicate to the receiver that this dog won’t fight. But communicating information is not their
primary function. Maximizing fitness
comes first; communicating information is incidental to that, and the fitness
enhanced is the sender’s, not the receiver’s.
However, while language as a whole may be adaptive, there is no sense in
which the units that compose it (words, phrases etc.) in and of themselves
contribute in any way to the sender’s fitness.
Indeed, the reverse is often closer to the truth: if I give you
information via language, that information may increase your fitness, but it’s
hard to see how (bar a pious hope for reciprocity) it could increase mine, and
if it gives you an advantage over me it could actually diminish my fitness.
By what metric does one
decide that the “doing-things-to-each-other” property outweighs the properties
of animal signals that distinguish them from language? I don’t know, but inevitably one suspects that
the property in question has been chosen simply because it is the only one that
yokes language and animal signals together, and consequently the only one that
accords with the belief that the one is the true ancestor of the other.
The belief that cognitive and
communicative capacities of great apes brought them to the brink of language
inevitably suggests that such capacities must have developed gradually and
progressively across the phyla, starting from humble beginnings among simple
organisms and reaching some kind of climax among bonobos and chimpanzees—in
Hurford’s own words (cited above), that “our animal ancestors approached modern
human cognition to various degrees”. In
fact, communication systems of other animals show no sign of approaching anything,
least of all richer and more complex cognitive and communicative systems. Such local peaks as there are in the fitness
landscape do not increase in height or number as we get nearer to humans. “Functionally referential” alarm calls,
supposedly as close as other animals get to words, are found among monkeys and
even chickens, but Hurford cannot adduce a single example from our closest
relatives. Number of signals per system
falls into the lower range of double digits, regardless of whether primates or
fish are involved. There are no clear
cases of calls concatenating or modifying one another, and none of the tiny and
highly controversial handful of cases that have
been claimed involves any of the great apes.
The state of affairs in communication is mirrored by other advanced
capacities; Caledonian crows show at least as much dexterity in making tools as
any ape, and the episodic memory of scrub jays at least equals that of any
mammal. Far from a steady march towards
heightened powers, what one sees looks more as if someone had shaken up a
jarful of varied abilities and then scattered them randomly across the phyla.
But what might look random
from a progressive perspective is anything but random when seen from the
viewpoint of evolutionary biology. Here
there is no “approaching” of anything; species get the particular cognitive and
communicative skills they need in order to exploit the particular niches that
they have chosen or constructed, and once they have those skills, Nature,
wholly uninterested in perfecting the type, simply stops selecting. Hurford
gives a favorable mention to niche construction theory, and I kept hoping he
was going to draw the conclusion I drew from it: that the key to the origin of
language must be sought somewhere among the niches constructed by human
ancestors between the date of the last common ancestor of humans and other apes
and the present—niches very different from any occupied by other apes. But he did not.
He did not, for a very
interesting reason. I spoke earlier of
how well Hurford covers evidence from a variety of fields. But there is one startling omission—at least,
one that would be startling, were it not found among so many other writers on
language evolution. He virtually ignores
anything to do with human evolution.
Only two of the numerous species ancestral (or possibly ancestral) to
humans, habilis and erectus, are even mentioned, and each
species is mentioned only once in the entire volume. Moreover, these mentions are not even
Hurford’s, but merely brief and tangential references in passages from other
authors that he cites! He seems unaware
that in ignoring the overall pattern of human evolution he is not only closing
the most promising avenue to the origins of language but also falsifying the nature
of the human ancestors who first developed language, for whom forest-dwelling,
at least partially arboreal apes make very poor ecological models.
In consequence, it is hardly
surprising that when it comes to actually specifying what was the tipping point
from call-system into language and what pressure drove our ancestors past that
point, Hurford has nothing substantive to offer. Granted, his case is that minor improvements
in ape cognition and communication gradually accumulated until some progenitor
of humans became “language-ready”, so that the actual transition to language
was no big deal. But any such claim
sends its maker spinning into the vortex of Charybdis. If these minor improvements accumulated in
one ape species, why not in all, or at least one or two others? Why are these improvements not continuing in
modern apes, so that we can observe them in action? Why is it that while we have thousands of
complex languages with convoluted structures and tens or hundreds of thousands
of words in each, they have communication systems resembling those of birds and
fish? Why, while we are making
moon-landings and sonatas, cathedrals and concentration camps, are they still
fishing for termites and cracking palm-nuts?
Nobody as intelligent as Hurford
could fail to be aware that, without at least some account of the
tipping-point, his book is seriously incomplete. Indeed, in at least one place he is commendably frank about this; to a
reader who complained that “[Chapter 8] needs a more powerful conclusion that
matches the great expectations created in the introductory pages” (305), he
responds “I’m sorry, but we have to be honest…Humans, with the emergence of
language, appear to have squeezed through an evolutionary loophole, and it is
hard to specify exactly which combination of the factors discussed in this
chapter provided that loophole” (ibid.).
The most he does is to suggest the emergence of shared intentionality,
plus elevated levels of oxytocin—a chemical that appears to induce trust, in
this case trust in the honesty of cheap words.
Such things, of course, raise more questions than they answer. How did shared intentionality evolve? What selected for it? Why wasn’t it selected for in other
species? What caused oxytocin levels to
rise in humans? Why didn’t they rise in
other species, or if they did, why didn’t they have the same results as they
did in humans? These aren’t solutions,
they’re just additional problems. Yet
the penultimate paragraph of the book commences: “We have reached a
watershed. As soon as the breakthrough
was made for animals to communicate their thoughts freely to others, a cascade
of other innovations were (sic) selected…” (333).
Breakthrough? What breakthrough? Early last century there was a genre of
serial magazine adventure stories for boys in which at the end of each episode
the hero was caught in some trap from which there seemed no way of escape. The reader bit his nails for a week,
wondering by what incredible miracle of ingenuity the hero could survive for
the next week’s adventure, only to find the new installment beginning with some
such sentence as, “With one bound, Jack was free.” Well, having made the breakthrough sound as
impossible as any of Jack’s predicaments, Hurford transitions to his next volume
in exactly the same way. With one bound,
Jim is free to continue the story of language in his second volume.
I hope you’ll read that
volume, as I certainly will, and I hope that nothing I have said will prevent
you from reading the present one. Whether
you agree with it or not, it’s a must-read for anyone who’s ever had the
slightest interest in language evolution, or in how humans came to be human, if
it comes to that. Hurford is always a
stimulating and thought-provoking writer, and never more so than here; proof of
that stimulation can be found in this very review, where his book has forced me
to sharpen and express my own ideas in ways I had not imagined before. I doubt if anyone will produce a more
competent and thoroughgoing defense of what Irene Pepperburg (2005) called the
“primate-centric” position. Those who
would challenge that position, from whatever perspective, must be able as a
minimum to answer all of Hurford’s arguments, or abandon their enterprise
altogether.
References
Bickerton, D. 1995. Language and human behavior.
of
Hurford, J.R. 1989.
Biological evolution of the Saussurean sign as a
component of the language acquisition
process. Lingua 77.187-222.
________. 2003.
The neural basis of predicate-argument structure.
Behavioral
and Brain Sciences 28 (3).261-283.
________, J.R.,
Studdert-Kennedy, M. & Knight, C. (eds.)
1998.
Approaches
to the evolution of language; social and cognitive bases.
Knight, C, Studdert-Kennedy,
M. & Hurford, J.R. (eds.) 2000. The
evolutionary emergence of language.
Press.
Penn, D.C, Holyoak, K.J.,
& Povinelli, D.J. (in press)
explaining the discontinuity between human
and nonhuman minds. To
appear in Behavioral and Brain Sciences
Pepperberg, I.M. 2005.
An avian perspective on language evolution:
implications of simultaneous development
of vocal and physical object
combinations by a Grey parrot (Pittacus erithacus), In Yallerman, M.
(ed.),
Language origins, 239-61.
Tomasello, M., Carpenter, M.,
Call, J., Brehne, T., & Moll, H.
2005,
Understanding and shared intentions: the
origins of cultural cognition.
Behavioral
and Brain Sciences 28.675-735.