Left Brain vs Right Brain

• Bridge between left and right hemispheres of the brain

Figure 13.3 The cerebral commissures
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Figure 13.5 The route of visual input from the right and left visual fields to the right and left hemispheres
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

The left hemisphere is dominant for speech and language

Figure 13.6 The difference between normal (intact brain) and split-brain individuals
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Figure 13.6 The difference between normal (intact brain) and split-brain individuals
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Picture of fork is on the left side of the screen
• Patient sees a picture of a fork in the left visual field
• Information is process in the right hemisphere
• Right hemisphere is mute

Picture of fork is on the left side of the screen
• Left (language) hemisphere does not see anything
• Patient says “I don’t see anything.”
• Yet, patient can reach under the table with left hand (which is controlled by the right hemisphere) and pick out a fork

What if picture of fork is on the right side of the screen?
• Patient sees a picture of a fork in the right visual field
• Information is processed in the left hemisphere
• Left hemisphere lets patient say “fork”

What if picture of fork is on the right side of the screen?
• Left hemisphere tells the right hand “fork”, right hand reaches under table and picks out an fork

Figure 13.7

What about the right hemisphere?

• Metaphors
• Humor/jokes
• Context (We saw her duck.)
• Emotional aspects of language (e.g., tone)

• Coordinating vision and movement
• Finding your way around

Figure 13.8

Table 13.1
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

• Noam Chomsky
• Universal sequence of language development
– Nonsense sounds
– One word
– Two words
– Telegraphic speech
– Complex sentences
• Language acquisition device (LAD)

• The child needs to be exposed to a language
• Age matters
• Among immigrants who arrive…
– Before age 4: understanding of grammar is as good as native speakers
– Age 11-15: 80%
– Age 17-39: 75%
• Deaf children and sign language

Describe what is happening in this picture
Figure 13.15 A picture from the
Boston Diagnostic Aphasia Examination
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Describe what is happening in this picture
#1
“Water dripping. Boy” (pointing to girl)
“Girl (pointing to boy)
“Okay. Okay… Mother… Mother.”
([Examiner asks] What’s going on?)
“No.”
Goodglass & others, 2001a, p. 64

Describe what is happening in this picture
#1
Figure 13.16 The handwriting of a person with Broca’s aphasia
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Describe what is happening in this picture
#2
“And their falling is scooting that over just getting ready when they have apparently when they want to get it…
He was, he was doing usual, but he has been following water all over the place over here, pushing over that, and the process if doing that, he’s sitting on in and all that sort of stuff, but it wasn’t a bother.”
Goodglass & others, 2001a, p. 68

Describe what is happening in this picture
#2
Figure 13.18 The handwriting of a person with Wernicke’s aphasia
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

• Difficulty producing or understanding language

Figure 13.1 The Wernicke-Gershwind model of language
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Figure 13.14 MRI scans of a patient with Broca’s aphasia
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

• Damage to Broca’s area (left prefrontal cortex)
• Few problems with comprehension of language
• Can understand what other people are saying
• Cannot speak or write normally

Describe what is happening in this picture
#1
“Water dripping. Boy” (pointing to girl)
“Girl (pointing to boy)
“Okay. Okay… Mother… Mother.”
([Examiner asks] What’s going on?)
“No.”
Goodglass & others, 2001a, p. 64

• Agrammatical speech
– Absence of a, an, the
– Verb tense
– Problems understanding sentences with complex grammar
• Poor handwriting
• Problems with selecting correct word
– More problems with verbs than with nouns
X

• Hearing impaired people with Broca’s aphasia
– Have trouble producing sign language
– Able to use hands well in other ways
X

Figure 13.1 The Wernicke-Gershwind model of language
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

Figure 13.17 MRI scans of a patient with Wernicke’s aphasia
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers

• Damage to the left temporal lobe
• No problem producing language, talk fluently
– But makes no sense

Describe what is happening in this picture
#2
“And their falling is scooting that over just getting ready when they have apparently when they want to get it…
He was, he was doing usual, but he has been following water all over the place over here, pushing over that, and the process if doing that, he’s sitting oon in and all that sort of stuff, but it wasn’t a bother.”
Goodglass & others, 2001a, p. 68

• Difficulty with language comprehension
• Paragrammatical speech
– “you” instead of “for you”
– “he” instead of “she”
– “pork” instead of “fork”
• Do not appear frustrated with difficulties

• Alexia
– Inability to read
• Agraphia
– Inability to write