Task 6- Consciousness

Question 1

What is a split brain?

Answer 1

Commissurotomy: surgical transection (cutting) of the corpus callosum (=important for communication between right and left hemispheres)

Question 2

What is the ‘other minds’ problem?

Answer 2

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?

Question 3

What is the criterion/bridging principle for C according to Eccles?

Answer 3

• IVR (Introspective verbal report)

- -> Right hemisphere is not conscious

Question 4

What is the criterion/bridging principle for C according to Sperry?
-Dual C?

Answer 4

• Dual C -> two separate C’s if split brain
• bridging principle: intelligent behaviour
• unified C if intact (-> Emergent interaction theory)

Question 5

What is the original criterion/bridging principle for C according to Gazzaniga?

• Dual C?
• What is his argument about C based on?

Answer 5

• 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

Question 6

How did the observation of an ‘alien hand’ support evidence for C in the right hemisphere?

Answer 6

• 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)

Question 7

What is cross-cueing and how does that support evidence for C in the RH?

Answer 7

-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

Question 8

How does visual processing works?

Answer 8

• 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

Question 9

Which functions are primarily in the left hemisphere (=LH)?

Answer 9

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”

Question 10

Which functions are primarily in the right hemisphere (=RH)?

Answer 10

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

Question 11

Are the differences between right and left hemispheres absolute?

Answer 11

No, they are relative

Question 12

What does the ‘Left brain, right brain mania’ say?

Answer 12

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

Question 13

How does the experiment with z-lenses support evidence for C in RH?

Answer 13

• 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

Question 14

Which two psychological constructs can be seen when blocking the right visual field with z-lenses?

Answer 14

Self recognition and social values

Question 15

Why is split-brain research so hard?

Answer 15

1. Most people with one had a severe epilepsy
2. Only few split-brain patient
3. Split brain subjects show considerable variability among themselves

Question 16

What is the object identification task?

Answer 16

Naming object by feeling it

Question 17

What are the results of the unilateral testing/object identification task?

Answer 17

• LH knew what object the right hand had felt and named it accurately
• RH could not name what the left hand had felt
• -> right hemisphere knew what the left hand had felt because it could show how to use it e.g. while blindfolded, subjects could use the left hand to show how to use a spoon or a paintbrush, using appropriate motions

Question 18

What is the T-scope test?

Answer 18

objects only presented a short time so that both visual fields do not process it

Question 19

What are the results of the T-scope test regarding the two hemispheres?

Answer 19

• left hemisphere can name what it sees
• the right hemisphere knows what it sees, but cannot name it -> could read common nouns, and select the corresponding object by touch and can initiate an emotional reaction

Question 20

What is the block-design test?

Answer 20

subject is required to use a set of colored blocks to construct a pattern that matches a sample pattern shown in a picture

Question 21

What are the results of the block design test?

Answer 21

• construct the correct block pattern quickly and easily using their left hand (RH)
• find the task difficult or impossible with their right hand (LH)

Question 22

Which hemisphere is superior in what according to the block design test?

Answer 22

manipulo-spatial superiority of RH

Question 23

Which hemisphere is better at recognizing faces and under which circumstances?

Answer 23

• RH’s superiority at face recognition was limited to tests involving similar faces, in which it was hard to discriminate between the different faces
• LH did a good job when faces were very dissimilar

Question 24

What does Gazzaniga mean with modules?

Answer 24

independent functional units that can receive information, compute, store and retrieve memories, trigger emotional reactions and produce behaviour

Question 25

What is an 'interpreter system' according to Gazzaniga?

Answer 25

- special module - tries to interpret the diverse actions of the various modules, to explain why they occurred, and to fit them into the narrative sequence of events of our lives and conscious experience

Question 26

Where is Gazzaniga's 'interpreter system' located according to him?

Answer 26

only in left hemisphere

Question 27

What is eventually Gazzaniga's bridging principle after conducting his experiments?

Answer 27

- presence of interpreter system - C: associated with activity of interpreter system - ->Normally occurs only in LH, but it is not the language system itself

Question 28

Which kind of C is Gazzaniga's interpreter system similar to?

Answer 28

similar to the idea of reflective consciousness

Question 29

What does the evidence eventually suggests with respect to which kind of C do the hemispheres have?

Answer 29

- both LH and RH have primary consciousness | - reflective consciousness may be limited to the LH

Question 30

What does the partial- consciousness model say?

Answer 30

- only LH gives rise to C - RH only processes information in an unconscious manner - RH might prime LH towards certain behaviour, but this will only affect C after it has been molded and interpreted by LH

Question 31

What is the split-consciousness model?

Answer 31

- by Sperry - in a split-brain patient each hemisphere has its own C; each has its own sensations, perceptions and cognitive processes

Question 32

What are the 5 hallmarks observed in split-brain patients?

Answer 32

1. Response * visual field interaction (when stimulus is presented to LVF , patient can only respond adequately with left hand) 2. Hemispheric specialization 3. Post hoc-confabulations (after actions with the left Hand -> Alien hand) 4. Split attention 5. Incapacity of comparing stimuli across the midline

Question 33

Which 3 of the 5 hallmarks exist also in patients with unified C?

Answer 33

hemispheric specialization, post hoc confabulations (e.g. gaps in memory) and split attention

Question 34

Is there object-based attention in split brain patients in LVF/ right hemisphere?

Answer 34

No

Question 35

What does the “Conscious unity, split perception model” say about C?

Answer 35

* C is unified in split-brain patients -> are still one conscious agent in control of their entire body and thus feel mostly unchanged * This one agent experiences entire visual field and controls his/her entire body * Easy to respond to stimuli anywhere in the visual field, with any response type

Question 36

How does the “Conscious unity, split perception model” explain differences from healthy patients?

Answer 36

due to unintegrated perception

Question 37

How does the analogy to an out-of-sync movie relate to a split perception?

Answer 37

perception split because you experience a visual and an auditory stream -> unable to integrate these two streams

Question 38

How does the “Conscious unity, split perception model” explain hemispheric specialization?

Answer 38

contralateral hemisphere does all the visual processing -> leads to maximal hemispheric specialization

Question 39

What is the basis for a unified C according to the “Conscious unity, split perception model”?

Answer 39

* 1. Subcortical areas are still unified in split-brain patients * 2. Functional unity -> when connected to common source (e.g. thalamus); indirect connections

Question 40

How does the “Conscious unity, split perception model” challenge the Integrated Information Theory?

Answer 40

Integrated information theory -> says that C is split

Question 41

How does the “Conscious unity, split perception model” challenge the Global Workspace Model?

Answer 41

Global workspace -> headquarter | -implies that partial or split C arises

Question 42

Does the “Conscious unity, split perception model” challenge the Recurrent Processing Theory?

Answer 42

- local processing -> phenomenal C only - unified, reportable C: you need both hemispheres - -> kind of compatible w/ model