Lecture 4 - Language and the brain Flashcards
(21 cards)
What is the social brain hypothesis (Dunbar 1998)?
social complexity drives primate cognition
What is the cultural intelligence hypothesis (Van Schaik et al 2011)?
co-evolution of cognition and culture
Foraging brain hypothesis?
- new research comparing 140 primate species suggests diet not sociality better predicts brain size expansion in primates
- specifically eating fruit and extractive foraging
Brain size in genus homo?
- homo habilis (first member of the genus homo) show evidence of Broca’s area
- homo erectus = larger brains and bigger body size
- brain size doubles between homo Erectus and Homo sapiens
Brain evolution and language?
- rapid increase in homo brain size during a period of dramatic climate change
- Homo sapiens were likely to be the first linguistic species
- language cannot be time stamped as it’s a very gradual process with many blocks already in place
What is the mirror neuron system?
- discovered by Rizolatti and colleagues in 1992
- mirror neutrons match observed and executed actions
- ‘monkey do, monkey see’
- they are implicated in language, imitation , action learning, action understanding and empathy
What is the Gestural theory of language evolution?
- Corvallis (2010) argues that language evolved ‘hand to mouth’ starting with gestures
How do mirror neutrons contribute to language?
- they are active during speech perception
- they contribute to complex control systems in low level ways
What is the left hemisphere of the brain responsible for?
- analysis of sequences
- comprehension/ production of speech and language
- logic, reasoning, analysis
What is the right hemisphere of the brain responsible for?
- visual-spatial skills
- processing space and geometrical shapes including faces
- organising a narrative
- understanding speech rhythm and intonation (prosody) = they way we speak
- recognising and expressing emotions of speech
- music
Split brain?
- epileptic activity can spread from 1 hemisphere to the other through the corpus callosum
- in the 1950s-60s epilepsy was treated by severing the corpus callosum
What did research from Sperry and Gazzangia find?
- left hemisphere = read and verbally communicate
- right hemisphere = identify visuospatial info, could not linguistically communicate
- only processing occurring in the left hemisphere could be described
- also found evidence of hemispheric neural plasticity
What is Broca’s area?
- important region for language production
- located in the left inferior frontal cortex
What is Broca’s aphasia?
- is caused by lesions to Broca’s area
- causes problems in language production
- speech = non fluent, laboured and hesitant
- comprehension = relatively intact
- partial paralysis of the body
What is Wernicke’s area?
- important region for language comprehension
- found in the temporoparietal junction of the posterior temporal lobe
What is Wernicke’s aphasia?
- caused by lesions to Wernicke’s area
- problems in language comprehension
- speech is fluent but meaningless
- patients cannot repeat words or sentences and cannot recognise speech sounds
- no paralysis
What is a problem of bilingualism?
- verbal skills of bilinguals are generally weaker than those of monolingual speakers (Bialystock et al. 2013)
What are some benefits of bilingualism?
- show better executive control (Bialystock et al. 2013)
- executive control = cognitive skills like inhibition, attention and working memory
Joint activation?
- there is neural evidence of joint activation of both languages during bilingual linguistic processing even when focused on 1 language
- bilinguals must select the language from competing options and selectively attend (Krollet et al. 2006)
Bilingualism and mental flexibility?
- fMRI research shows bilingualism leads to grey matter changes
- e.g. Michelle et al. 2004 found that Italian-English bilinguals had higher grey matter density in left inferior parietal regions than English monolinguals
- Peal & Lambert 1962 said that bilingual people have mental flexibility and a more diversified set of mental abilities
How do you assess bilingualism?
- is difficult and depends on factors such as age and duration of exposure
- children may be bilingual but not biliterate