Mind Brain and Behaviour

1
Mind Brain and Behaviour

• The Evolution of Language

2
Is language ability innate?
While the behaviourists claimed that language was
just verbal behaviour, the influential
Chomskyian view holds that all humans have an
innate capacity for language. But Chomsky
believed that language was not subject to
selective forces, but was an emergent feature of
increasing brain size. From an evolutionary
perspective, it has been argued that a language
ability is both species-specific and
adaptive. What selective pressures may have led
to the emergence of language in humans? And how
exactly does human language differ from the
communication of other species?
3
Features of human language
Hockett (1960) - some features of human language
may not be found in animal communication, and
thus could be considered defining features of
language.

• Productivity (creation of new utterances)
• Displacement in time and space
• Arbitrariness (no physical similarity between
  words and meanings)
• Cultural transmission

4
Vervet language?
Vervet monkeys produce different types of vocal
alarm calls to signify different types of
predators (leopards, eagles and snakes). Such
calls may be more expressive than symbolic, and
are unlikely to be the precursors of human
language.
5
Ape Language studies
Hayes Hayes - Viki (problem of
vocalisation). Later studies used sign languages
or artificial lexigrams.
Gardner Gardner (1960s) taught Washoe ASL in a
family environment. Washoe learned over 100
signs, including qualifying words like more.
She learnt to produce signs spontaneously and in
appropriate contexts. Most signs were used to
request food or treats like tickles.
6
Can apes be creative?
Other studies Premack (1960s) taught an
artificial symbol language to a chimp called
Sarah. Rumbaugh Savage-Rumbaugh started work
with chimps and bonobos in the 1970s using an
artificial lexigram.
Such artificial languages show one of the key
design features of human languages
arbitrariness. Some of these animal subjects also
seemed to show an ability to create novel terms
and utterances. Upon first seeing a swan, Washoe
signed water bird a novel sign combination for
her. Lucy, another signing chimpanzee, tasting
radishes for the first time, signed the novel
combination hurt cry food.
7
Some of these studies also suggest that apes can
use language to refer to objects not physically
present in time/space. Francine Patterson works
with a gorilla called Koko, who has been taught
to use ASL. The passage below is an exchange
between Koko and a researcher, discussing her
birthday which had been celebrated the day before.
B How about telling me about your birthday, was
it a nice one? Koko Visit gorilla Koko-love. B
What did you like best? Koko That. (to a velvet
ribbon she received as a present.) B What else
did you like? Koko Cat tiger. B Wow, you got a
cat!
8
Criticisms
Terraces study of Nim Chimpsky (1970s). Terrace
suggested that the sentences that Nim signed were
simply imitations or reflections of those of his
trainers. Nim rarely signed spontaneously, or to
make communications not related to goals such as
food. However, Terrace used criteria of spoken
language applied to signing language (there are
clear differences between them). Later
researchers suggested that Nims progress was
hindered by the lack of a stable social
environment.
9
Language as social tool
The importance of the social context within which
language is taught has been shown by
Savage-Rumbaugh in her work with the bonobo
Kanzi. Kanzis language acquisition and use has
been structured around social situations (which
is the way that children learn language).
Kanzi indirectly acquired the ability to use an
artificial lexigram during attempts to teach this
to his mother Matata. Kanzi appears to be able
to use communication to interact spontaneously
with his trainers, and is able to respond to
spoken commands.
10
While many species have sophisticated forms of
communication, the relative success of teaching
artificial languages to apes, dolphins and birds
suggests an important link between language and
complex social abilities (including the ability
to communicate across the species barrier).
Pepperbergs work with African Grey parrots
suggests that birds, as well as mammals, have
complex cognitive abilities http//www.alexfounda
tion.org/cognition/index.html
However, tutored nonhumans do not develop the
complexity and spontaneity of human language use
(but see Marlers suggestion that bird song may
be a closer analogy to human language.)
11
Is human language special?

• Ape language use is similar to that of a 2yr old
  child, but children subsequently show an
  explosion of language use after this age.
• Evolutionary psychologists suggest that humans
  have an innate, specialised language module.
  Evidence for this view
• Children learn language incredibly rapidly
• Language disorders are inherited
• The structure of the human vocal tract and
  auditory system suggest shaping for language
• From an evolutionary perspective, it would be
  more efficient for NS to produce specialised
  mental modules for important abilties like
  language. A general learning mechanism that has
  to cope with decisions about many different
  aspects of experience would be more error-prone.

12
There is also evidence that language use is
linked to specific areas of the brain Brocas
area seems important for grammar, and Wernickes
area important for language comprehension.
But Greenfield and others suggest that until age
2, language use seems more the product of a
general purpose learning program rather than a
specialised module (capacities for object
manipulation and language in young children seem
to initially rely on the same processes). Apes
may also be using generalised learning rules to
acquire artificial language. Karmiloff-Smith
(1992) suggests that there are domain-specific
modules for abilities like language, but that
these modules gradually begin to work together
allowing humans to combine knowledge from
different domains. She suggests that the
plasticity of early brain development means that
the cultural context determines the types of
different domains that appear.
13
When did language emerge?
Language seems to be specific to Homo species.
Early humans show disproportionate increase in
pre-frontal cortex (Deacon). Casts of fossilised
skulls indicate possible evidence of development
of Brocas area in Homo habilis, but not in
australopithecines. Vocal apparatus probably in
place about 350,000 yrs ago. In both archaic Homo
sapiens and Neanderthals, the vocal apparatus and
brain capacity and structure indicate an ability
to vocalise, if not the capacity for language.
In early humans we see both an increase in brain
size and also clear evidence of the manufacture
and use of stone tools like handaxes for the
preparation and cutting of carcasses.
14
Language or gesture?
Hewes and later writers suggest that early humans
communicated via gesture, and that spoken
language was a later emergence. Evidence that
early humans were bipedal, and had good manual
control and good vision, favouring a gestural
language.
The open savannah environment in which early
humans lived would have encouraged the
development of social cooperation. The ability
to be able to sign to each other (silently) about
predators would have been an advantage. Other
evidence for gestural origins of language deaf
children spontaneously acquire a gestural
language non-human primates naturally use some
basic gestures. Also our spoken language is very
much based upon metaphorical constructions.
15
Speech has added advantage of freeing up hands
(perhaps for tool use) and enabling communication
over longer distances. This may have led to the
cultural explosion in Homo sapiens sapiens of
complex tool use, art and religion (all of which
are absent from earlier humans and nonhuman
primates).
Humans living in Paleaolithic period show
practices such as burying the dead with grave
goods. Also, tools now made from materials other
than stone. All this implies more complex social
systems and the beginnings of a shared system of
cultural beliefs and meanings.
16
Group size and language
Dunbar presents evidence that development of
language is tied to the complexity of social
groups. As group size increases, more time needs
to be found for grooming. He proposes that
language evolved to meet this selective pressure.
Language is a more efficient way of exchanging
social information (allows communication with
more than one individual at a time, frees the
hands to do other things such as use tools).
Using equation relating brain size to group size,
the brain size of early humans suggests
increasing group size for later Homo species
(chimps group size 60 Australopithecus 67
Homo sapiens 131). He estimated relationship of
group size and grooming time (from living
primates), then used this to calculate social
grooming requirements of early humans as being
23 of time budget. Those reducing this time by
using vocalisations to communicate may be at a
selective advantage.
17
Grooming and gossip
Dunbar suggests that human language serves a
similar function to extended grooming in other
primates it enables the maintenance of social
bonds, and serves to increase the exchange of
social information about conspecifics.
Evidence from modern hunter-gatherer societies
suggests they live in groups of about 150
Dunbars predicted cognitive group of early
humans. The cognitive group consists of
individuals a person would have some social
knowledge of (but not necessarily interact with
on a day-to-day basis).
18
What does an evolutionary approach offer?
Some have criticised Dunbars proposal as
tenuous, but it seems clear that, whatever the
nature of early language, the most likely
selective pressure for its development was
increasing compexity in early human social
groups. However, the evidence that modern humans
possess specialised language modules that require
little environmental shaping for their expression
is much more equivocal. In its reliance on
info-processing view of mind, EP tells us little
about how thought and language develop, and
little about their structure. The data
processing mechanisms posited to explain thought
are vague, reductionistic and difficult to
investigate. EP approach to language and
cognition seems similar to black box
cognitivism rather than detailed and testable
hypotheses about human experience.
19
Language and culture
Although it is clear that a language ability is
universal, language is closely linked to the way
in which we structure and categorise our world,
and therefore closely related to culture and
experience. While there may be basic
similarities in cognition (e.g. spatial image
schemata like our experiences of up and down may
be universal) there are also large cultural
differences in the way that we comprehend
experience.
Whorf found clear differences between Western and
Hopi indian views of the world. For instance,
the Hopi have a different perception of time and
do not distinguish between past, present and
future. Today, our perception of time seems to
reflect our economic system (time is a resource).
20
F. David Peat studied language and conceptual
thought in Native Americans of Turtle Island.
Suggests Western European languages more
object-based some Native language focus more on
relationships and process.
Basic difference in categorisation, e.g. between
animate and inanimate objects A non-native
friend of mine had been told that while rocks are
animate, not all of them are alive. Well, which
ones arent alive? he asked. The ones that
dont breathe. was the reply. Peat (1995,
p.231). Algonquin languages refer to patterns of
animation within the water, rather than a
category of fish. When we enter the world of
Indigenous American languageswe encounter
profoundly different concepts and worldviews.
Indeed, not only are the concepts enfolded within
the languages radically different, but even the
meaning of language itself and the function of
the sounds people make is profoundly different.
Peat, p. 222. The languages and conceptual
systems of indigenous cultures are not primitive,
rather they provide a contrast to our Western
urban-industrial perspective.
21
Summary and key points
Evidence from animal language studies suggests
that, while trained animals do seem to use
language in a complex and creative way, patterns
of language development and use in humans are
very different. Along with evidence from the
fossil record, such studies (as well as natural
communication patterns in animals) indicate that
language may have evolved in the face of
increased social complexity, and language may
have facilitated the development of complex tool
use, art, religion and culture. EP suggests that
humans developed a specialised module for
language, and therefore that language ability is
not greatly shaped by culture. Evidence for
developmental studies suggests that young
children show a more generalised language
capacity. Rather than being universal, language
and some conceptual categories can be heavily
structured by culture.
22
References
Cartwright, chapter 7 The Adapted Mind, chapter
12. Corballis, M. (1999). The Gestural Origins of
Language. American Scientist, 87, 2 (see online
readings on the bio web page). Aiello, L.
Dunbar, R.I.M. (1993). Neocortex size, group size
and the evolution of language. Current
Anthropology, 34, 184-183. Dunbar, R.I.M. (1996).
Grooming, gossip and the evolution of language.
London Faber and Faber. Savage-Rumbaugh, S.
Lewin, R. (1994). Kanzi The ape at the brink of
the human mind. London Doubleday. Deacon, T.
(1997). The Symbolic Species. London Penguin.
Peat, F.D. (1995). Blackfoot Physics A journey
into the Native American universe. London
Fourth Estate.