Chapter 10

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. 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 Gestural Theory of Language

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. Motor projection areas related to speech Broca’s area Auditory cortex Wernicke’s area 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

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. Universal Grammar • 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% men 25% women social leisure culture politics work

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?