How does human communication differ from animal communication?
- semanticity (use of symbols to refer to objects & actions)
- structure-dependence (use of grammar, or structured “chunks”)
- creativity (ability to create infinite combinations of symbols)
- Displacement (references to other points in time).
Does language set humans appart?
- Chimps and gorillas can be taught symbolic language (ASL) but, creativity is limited, especially with respect to syntax.
- abilities are roughly equivalent to a 2-year old child.
Is language separate from intelligence?
- Unlike most other cognitive skills, formal instruction is not required. (but must occur within a sensitive time period)
- language ability does not always correlate with intelligence (williams syndrome)
- mutation of the FOXP@ gene causes severe impairment in language learning
- language involves special brain structures that are lateralized.
How and when did language evolve?
- Modern forms of articulatory structures and FOXP2 gene evolved relatively recently (125-150 TYA) and are not present in apes.
- speech probability evolved from communication via gestures and vocalizations.
What do we know about the modularity of language?
- different aspects of language processing are localized in different brain regions.
- Evidence: aphasia, brain stimulation, functional neuroimaging
What is broca’s aphasia?
- impairment in language production
- 1 slow, effortful speech and writing (agraphia)
- 2 poor articulation
- 3 few function words
- 4 signs of frustration.
- relatively good comprehension. (problem with complex syntax)
3 damage to left frontal lobe.
What is wernicke’s aphasia
- Impairment in language comprehension (both spoken and written)
- relatively good production
- 1 grammatic, but devoid of meaning
- 2 problem with semantics rather than syntax.
- 3 lack of awareness of deficit.
- damage to left temporal lobe.
What is the Wernicke- Geschwind model?
- group of structures involved in language processing.
What is conduction aphasia?
- damage to arcuate fasciculus. (connection to wenickes and brocas areas.)
- intact comprehension
- fluent production, but often nonsensical
- impairment in word repetition
What is pure alexia?
- damage to angular gyrus- connection between visual cortex and Wernickes area
- selective deficit to reading
How does aphasia effect deaf singers?
- Damage to brocas and wernicke’s areas produces deficits in ASL production & comprehension, respectively.
- strongly suggests these areas are specialized for communication, not limited to spoken language.
what is lateralization of function?
- the localization of a neurological function in one hemisphere or the other.
- loosely related to handedness
- observed in other species
- causal factors are poorly understood.
Whats up with split brain patients?
- disconnected between the two hemispheres
2. a surgical treatment for severe epilepsy.
How do you test for split brain?
- Tested by presenting a visual stimulus in only visual field (i.e. to one hemisphere)
- the RH can comprehend simple words and commands, but cannot produce language.
- The LH is specialized for language.
Music and intonation (RH)
- right temporal lobe damage produces impairments in- music recognition (amusia), voice recognition (phonagnosia) and other tonal aspects of speech.
spacial perception (RH)
Right inferior parietal lobe damage produces neglect
2. right fusiform gyrus (occipito-temporal) damage produces a deficit in face recognition (prosopagnosia)- impaired “holistic” processing.
