Task 6- Consciousness Flashcards
What is a split brain?
Commissurotomy: surgical transection (cutting) of the corpus callosum (=important for communication between right and left hemispheres)
What is the ‘other minds’ problem?
to left hemisphere, the right one is an “other mind”; can only make inferences based on emotional reactions and behavior
–> Is the right hemisphere conscious?
What is the criterion/bridging principle for C according to Eccles?
- IVR (Introspective verbal report)
- -> Right hemisphere is not conscious
What is the criterion/bridging principle for C according to Sperry?
-Dual C?
- Dual C -> two separate C’s if split brain
- bridging principle: intelligent behaviour
- unified C if intact (-> Emergent interaction theory)
What is the original criterion/bridging principle for C according to Gazzaniga?
- Dual C?
- What is his argument about C based on?
- IVR-> one consciousness
- bridging principle: language ability
- argues that right-hemisphere consciousness is rare in split-brain patients, and that when it occurs it is highly correlated with the presence of language abilities in the right hemisphere!
- -> based on patient P.S. -> could not speak but arrange Scrabble letters
How did the observation of an ‘alien hand’ support evidence for C in the right hemisphere?
- alien hand -> intelligent action
- spontaneuous, voluntary action from left hand would support RH C
- sometimes left hand does smth (slammed a drawer while right hand wants to get a pair of socks from that drawer)
What is cross-cueing and how does that support evidence for C in the RH?
-inadvertent cross-cueing: left hemisphere interpreting responses that were made spontaneously but unintentionally by the right hemisphere
-e.g. LH can report what RH has seen or felt
-e.g. ability to name color patches: when making mistake, head chuckled, right hemisphere could hear answer, changed his answer -> emotional reaction or deliberate cue of right hemisphere?
==> RH: conscious, independently of LH
How does visual processing works?
- General principle: left occipital cortex sees the right visual field (RVF) (=are to the right of the fixation point)
- RVF -> seen by left parts of eyeballs -> left parts of eyeballs get processed by left hemisphere
Which functions are primarily in the left hemisphere (=LH)?
o Language understanding and production -> cortex slightly thicker
o Superior at verbal and conceptual tasks
o Self-recognition
–> better at recognizing different faces
-> has been called “dominant hemisphere”
Which functions are primarily in the right hemisphere (=RH)?
o Spatial construction
o Superior at recognizing similar faces
o Manipulo-spatial superiority
o Drawing
o Making causal inferences and temporal discrimination
o Superior at recognizing musical melodies
o Creativity
Are the differences between right and left hemispheres absolute?
No, they are relative
What does the ‘Left brain, right brain mania’ say?
more accurate view is that in the normal brain different styles of thinking (rational, intuitive, imaginative) are complex processes that involve the interaction of different subsystems (or modules) within each hemisphere as well as interactions between the right and left hemispheres
How does the experiment with z-lenses support evidence for C in RH?
- Z-lens limits vision to left visual field (-> RH)
- Self-recognition in right hemisphere -> cannot verbalize it (cause that’s only possible in LH)
- emotional reaction (laughing) and RH trying to speak/articulate -> enable LH to speak/ say correct answer
Which two psychological constructs can be seen when blocking the right visual field with z-lenses?
Self recognition and social values
Why is split-brain research so hard?
- Most people with one had a severe epilepsy
- Only few split-brain patient
- Split brain subjects show considerable variability among themselves
What is the object identification task?
Naming object by feeling it