1. Chapter 10 The Evolution of Language

2. Language Language is communication, but not all communication is language Currently, unique to humans

3. Defining Language Vocal auditory channel Arbitrariness: symbols don’t inherently mean anything Semanticity: language means something Cultural transmission: cross generational Spontaneous usage Turn taking Duality: language sounds require ordering for sense Displacement: reference across time/space Structure dependence: grammar Creativity: can describe novel events

4. Components Vocabulary –Specific words with specific meanings Grammar –Rules for sequencing vocabulary –Allows “limitless” combining of concepts

5. Questions How language evolved –Gestural –Vocalization Why language evolved –Dunbar’s social gossip –Social contract –Scheherazade effect

6. Gestural Theory of Language Non-human primates use gestures Deaf children learn to sign readily Aimed throwing –Fine motor control and speech centres both localized in (usually) left brain Mirror neurons –Pre-motor cortex (F5) of macaques –Fire when observing another’s hand movement and during self-movement –F5 corresponds to Broca’s area in humans

7. Problems It’s a big step from gesture to speech Gestures not used to convey concepts or ideas Brain lateralization does not indicate common origin –Different neural circuits Recent mirror neuron findings show much more than motor function However, this doesn’t mean that gestural and vocalization communication couldn’t have evolved in parallel

8. Vocalization Theory of Language Non-human primates have elaborate vocalizations –Prosodic and semantic content Semantic content argument “Singing” argument –Synchronizing emotional states –Contact-calling choruses in non-human primates

9. Galogos Calls Nocturnal, arboreal African primates “Bush babies” Mouse to cat sized

10. Thick-tailed Bush Baby Calls: attract companions, repel rivals Presence of predator –Knocks...squawks...whistle yaps Loudness and pattern give information –To predator and other bush babies –Nature of threat –Distance Under attack –Yell; brings other bush babies to help

11. Juveniles separated from mother –Buzzing call 18 calls, each can have up to five meanings Calls depend on physical situation –High pitched calls Close quarters, want social contact –Low calls To communicate over distance

12. Species Differences Allen’s galagos –Dense undergrowth Low calls Elegant galagos –Open canopy top High calls

13. Sonograms “Vocal fingerprints” Can identify different species –Species and dialect differences Combine with physical details Dwarf galagos of West Africa –Not one species, but two –Thomas’: canopy –Demidoff’s: undergrowth 16 to 40+ species

14. Human Speech Good for information exchange Poor at conveying emotional state of feelings –Metaphor –Default to human-style “grooming”

15. Evolutionarily Selected Language production and comprehension neurologically “expensive” Costs –Can’t swallow and breathe at same time –Cognitive delay and/or distraction when speaking Benefits necessary to offset costs –Multitasking, don’t need to visually attend, communicating in dark Motor projection areas related to speech Broca’s area Wernicke’s area Auditory cortex

16. Learning Language Phonemes –Initially, can detect all phonemes –With experience focus on those of your own language(s) Ostensive communication –Associating a sound with an object –Learning words –Classification and categorization

17. Constraints Assisting Categorization Hierarchical elements in language learning Whole object assumption –Word applies to entire object Taxonomic assumption –“Basic level” classification –Word applies to related class of objects Mutual exclusivity assumption –Non-synonymous meaning of words

18. Attending to Others Learning assisted by attending to speaker of words Joint attention E.g., New sound spoken only applies to object if speaker is attending to it E.g., Children eye-track adults to determine what the new sound applies to Innate predispositions assisting language acquisition

19. Chomsky’s Universal Grammar Learnable argument –Language learning is too complex to simply be acquired through behaviorist associations Predisposition to grammatical structure –Innate –E.g., Children implicitly parse speech into noun, verb, and object phrases Universal Grammar

20. Different languages have different syntax and different grammar, but basic abstract properties common to all Person has limited set of parameters (“grammar switches”) that are activated through linguistic experience –Initially, any parameter combination is possible; experience determines which parameters will remain active

21. Universal Grammar and Evolution Chomsky argues for innate psychological mechanisms for learning language But, not adaptively selected for linguistic purpose Language “organ” exapted (co-opted) for current purpose from some earlier purpose

22. Genetic Basis for Language Likely a highly polygenetic condition –No single “grammar gene” Specific Language Impairment (SLI) –Inflectional morphology problems Using language deficits to study genetic basis Some SLI does run in families –E.g., Some genes on chromosome 7 implicated

23. Complications Hypothesis: regular nouns/verbs stored and a separately encoded “rule” used to change tense; irregular words need to be stored individual in each form SLI sufferers may lack ability to apply the rule, so every word must be stored separately Cognitively taxing for storage and recall Thus, genes related to SLI may not be grammatical genes at all…

24. Non-modular Evolutionary Account Michael Tomasello General pattern classifier interpretation –Species-specific and social cognition and cultural learning processes involved Children learn language by actively attempting to understand adult communication in context of attention sharing Theory of mind is essential –Language unique to humans due to humans’ greater level of identification with conspecifics

25. Why Did Language Evolve Earlier theories tended to focus on issues of hunting or teaching More recent evolutionary theories tend to be social (e.g., social bonding, courtship, mating) or social cognitive in their nature

26. Dunbar’s Social Gossip Theory Neocortex size, group size, and language Upper limit on group size –Cognitive constraints –Personal connections Non-human primates –Social connection via grooming –On average, about 20% of time budget –Positive correlation in apes and Old World monkeys

27. Group Size Group size ~20% of time –Limits group to ~50 members But, stable groups of ~150 members Grooming...43% Speaking...~20% –Converse with up to 3 others at once

28. Gossip: Benefits Beyond Group Size Relationships between individuals –Alliances, dominance, hierarchies, altruists, cheaters, etc. What do people talk about? 75% 50% 25% socialleisureculturepoliticswork men women

29. Gossip Increase in group size complicates social living Exchange social information Policing function in large groups –Warnings Reputation management –Advertise our own (or allies’) qualities Solicit/give behavioural advice

30. Policing Function But, most people don’t talk much about others’ misdemeanours; mainly discuss social relationships Why? –Cheating is not a serious problem? –Don’t like discussing cheating in public? –Policing is important, but isn’t an everyday occurrence?

31. Social Contract Hypothesis Mateguarding –Males away (hunting?); what are women doing? Need language to convey information on emotions, feelings, intentions –Abstract symbolic form –Mating fidelity –Regulation of living arrangements

32. Issues This theory takes pre-existence of large, socially bonded groups for granted –But why did the groups evolve initially? Non-human species can solve the same problem without language Verbal contracts do not ensure sexual fidelity Fidelity probably a problem in EEA –Language doesn’t seem to fix this –Expensive courtship rituals, investment, emotional bonding

33. Scheherazade Effect Language to attract, keep mate (Miller, 2000) –Entertaining people are the centre of attention Verbal skills as demonstration of genotype –Handicap principle Brain as sexually selected organ Lekking –Females better at verbal tests and show faster language development –Males have larger vocabulary and are more verbally flamboyant

34. Issues Miller argues that males are more artistically prolific than females –But, many socioeconomic factors could be responsible Unclear if language evolved as a way to attract a mate, or if this was a subsequent byproduct

35. Synthesis Language doesn’t fossilize No certainty as to when language evolved Likely a gradual process from communication to full, modern language Different theories could have held different value at different ancestral times Probably a combination of selective forces

36. Language and Group Membership Allusions and references –e.g., Biblical, Star Trek, comedy groups, etc. Dialect –Us/them –Honest signals of group membership –Rapid evolution Dialect to language –Vocal disguise Social strata and mating

37. Language and ToM Transmitting a specific message –Is the message received? Correctly? –Feedback Speech centres of brain small compared to frontal neocortex –ToM computationally difficult –Understanding your/another’s mind difficult; producing speech easier? –Saying what we mean; metaphor; oblique references; filling in the blanks

38. Language and Culture Are some languages better at explaining certain ideas, concepts, abstracts? –Latin vs. Greek –Postmodernist theory; French vs. English –Technical writing; German vs. English Selective/adaptive pressure?