It’s all about Communication (video)… Humans NEED comm’nCommunication.
Chapter 10 The Evolution of Language. Language Language is communication, but not all communication...
-
Upload
elaine-karin-norris -
Category
Documents
-
view
226 -
download
7
Transcript of Chapter 10 The Evolution of Language. Language Language is communication, but not all communication...
Chapter 10
The Evolution of Language
Language
• Language is communication, but not all communication is language
• Currently, unique to humans
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
Components
• Vocabulary– Specific words with specific meanings
• Grammar– Rules for sequencing vocabulary– Allows “limitless” combining of concepts
Questions
• How language evolved– Gestural– Vocalization
• Why language evolved– Dunbar’s social gossip– Social contract– Scheherazade effect
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
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
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
Galogos Calls
• Nocturnal, arboreal African primates
• “Bush babies”
• Mouse to cat sized
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
• 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
Species Differences
• Allen’s galagos– Dense undergrowth
• Low calls
• Elegant galagos– Open canopy top
• High calls
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
Human Speech
• Good for information exchange
• Poor at conveying emotional state of feelings– Metaphor– Default to human-style “grooming”
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 areasrelated to speech
Broca’s areaWernicke’s area
Auditory cortex
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
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
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
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
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
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
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
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…
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
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
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
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
Gossip: Benefits Beyond Group Size
• Relationships between individuals– Alliances, dominance, hierarchies, altruists,
cheaters, etc.
• What do people talk about?75%
50%
25%
social leisure culture politics work
men
women
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
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?
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
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
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
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
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
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
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
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?