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The Origins of LanguageJordan Zlatev

Lecture 10Why language evolved?

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Constraints on explanations

No “future utility” – evolution does not plan ahead!

Should benefit the individual (also), not just the group

Match timeframe and environment: hunter-gatherers, (mostly) on the savannah

Why not in other species? (The “why don’t chimps talk?” test…)

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Factors as “the main selective pressure” for language

Change in diet: Hunting and provisioning

Change in technology: complex tool-making

Change in sexual system Change in child care (and growth

pattern) Change in group size Change in social relations

Machiavellian intelligence (competition) “Christian” intelligence (co-operation,

empathy)

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Relevant traits: apart from language

Efficient bipedalism, allowing (long distance) running

Brain: three times larger, and at least in part, re-organized (rapid increase with H. erectus)

Larger groups, but still relatively “peaceful” (Partially) monogamous Neotony and unusually long childhood, then

sudden puberty (with Neanderthals) “Natural pedagogy” Technology – complex stone tools (with H.

erectus) Mimesis (imitation and pantomine/gesture)

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Finally…

There may be other adaptations, less directly related to language, but preparing the (long) road towards it…

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Hunting (and gathering)

Pro- Important both for hominines and for present hunter

gatherers (Kaplan et al 2000)- Increased levels with life in open habitats (also in

chimpanzees, baboons)- Requires “quality education” (Roebroeks 2001)- Increased levels of co-operation and possibly division of

labor (male/female)- Meat diet matches timeframe for brain growth and

stone tools Con- To a large extent present in chimpanzees (males),

possibly for “bonding”- A largely “silent activity” (Dunbar 2003)

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(Active) scavanging

Pro- Chimpanzees don’t scavange (Plummer &

Stanford 2000)- Large carcasses on the savannah – require large

groups, scouts, recruitment, displaced communication (Bickerton 2009)

- Not a “silent activity”- Meat diet matches timeframe for brain growth and

stone tools

Con- Chimpanzees scavange (O’Connell et al. 2002 etc)

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Tool-making

Con- Chimps and other animals use (and even

manufacture) tools too- A “solitary activity” in which language plays little role- Slow rate of change- No clear match between stone industries and species

(Davidson 2003) Pro- Acheulian tools mark a transition in complexity; with

H. sapiens a “clear acceleration of the pace of technological and cultural innovation” (:201)

- Even if not a direct factor for the evolution of language, a factor for mimesis (Donald 1991)

- “Sequential and combinatorial activity” (: 202): an exaptation for communication

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Sex

Pro- Clearly relevant: “if you don’t reproduce, you are an

evolutionary failure” (: 202)- Human reproductive systems are unique for mammals:

(partially, serially) monogamous, while maintaining life in (large) groups + paternal provisioning and collaborative hunting => symbolic communication (Deacon 1997)

Con- Communication/language not a matter of sexual

selection: clearly functional- Humans and chimps have similar levels of sexual

dimorphism- Not obvious that human sexual system is more complex

than that of chimps, and could even have been “mainly polygynous in the very recent past” (: 204) – Dupanloup et al. (2003)

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Child care and teaching

Pro- Unusual growth pattern: neotony,

childhood, sudden transition (Bogin 1999)- Parental – and group child care: less

(sexual) competition, more social learning- Active teaching: (near) universal, and

unique for our species Con- Cultures reported “without pedagogy”- Why adaptive for language, and not in

other species?

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Social relations

Pro- Large groups: ecologically “good”, but require

management of intra-group competition for food and mates

- “Solution to the dilemma lies in the evolution of social intelligence” (: 210) > brain growth

- Communication required to reduce the “cognitive arms race”, “vocal grooming” (Dunbar 1996)

- Motivation to provide information :“reputation” and social status are important for individual fitness (Dessalles 2004)

Con- Vocal grooming: “pleasant but meaningless noices”

(Bickerton 2002)- More emphasis on “politics” – competition and “reciprocal

altruism” rather than (true) empathy

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Other (non “crackpot”) factorsChildhood play: animals play, but not

“symbolically”Singing: a factor in the transition from

mimesis/gesture to speech (Burling 2005)Narratives: all cultures have stories and

most “myths”, and these require an elaborate, sequential, semiotic system (Donald 1991)

Visual art: not a cause, but not an obvious consequence of language either – still, an index of cultural (and cognitive) complexity

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Conclusion: no single cause, and hence explanation

A combination of factors (and theories) is necessary in order to explain the multiple ape-human differences, and their interrelation, such as a “scenario” relating: Bipedalism Complex social life Intersubjectivity (empathy, normativity) Mimesis (in skill and communication) Speech and narratives

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Bipedalism

Often explained as an adaptation to ecological changes: drier climate, life on the savannah, energy economy…

But the transition to bipedalism occurred earlier than the drying up of Africa around 3.5 million years ago

A possible explanation: apes stand on two legs when they need to “display” > in hominines: also for displaying… sexual parts (clear evidence for sexual selection)

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Bipedalism and intersubjectivity Freeing of the hands for other tasks

(carrying, tool making, gesturing) Changes in the birth canal: immature

infants, need for longer parental care Exaptation: more social learning (and play) for

children Adaptation: longer childhood, teaching

Selection for good “mothers and others” (Hrdy 2009): empathy and intersubjectivity

Selection for …“love” (Fisher, Maturana)

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Complex social life and mimesis Living in larger groups: negative “side

effects”: intra-group competition Vocal grooming, “song”: affiliation (Dunbar) Male hunting and provisioning, and food distribution

=> origin of “marriage”, a binding social contract (Deacon)

Selection pressures for mimetic skills: tool-use, and social learning

Exaptation for communication: representational gestures

Recruitment using displaced communication (Bickerton)

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Speech and narrative

Vocal communication More efficient than whole-body Vocal control trained independently by

song?

Narratives A “selective pressure” for the cultural

evolution of languages – the complexities of grammar are most functional for relating multiple propositions and discourse referents