Consciousness

Question 1

What does the problem of the inverted spectrum speak to?

Answer 1

The intuition that there is no [empirical] way to determine whether my colour experiences are the same as yours. I.e. whether we have the same colour experience when we talk about “red objects” or “blue objects”

Question 2

What does Jacksons thought experiement “Mary the colour scientiest” aim to prove?

Answer 2

That even if someone had all the physical information about brain states, this would not be sufficient to know what experience (f.e. of colours) is like from the first person perspective.

(Jackson himself takes this to refute phyiscalism, however this is highly contested, and Haynes doesnt seem to interpret/use the thought expirement this way)

Question 3

What are subliminal stimuli? Do they influence behaviour?

Answer 3

Sublimanl stimuli = stimuli below the (subjective) conscious perception threshhold

Influence on behaviour ONLY if action was already planed.

Question 4

What is the difference betweeen the subjective and objective conscioussness treshhold? Which one is lower?

Answer 4

Subjective threshold = report about presence of stimulus
Objective threshold = above chance guessing without (ability to) report of presence of stimulus

Objective threshold is more liberal/lower than subjective threshold.

Question 5

Brain activity in response to flickering of a screen without conscious awareness is an example of what?

Answer 5

Unconscious processing (=differential response (in this case neural activity in visual areas) to stimulus feature without awareness))

Question 6

What is the phenomena of blindsight?

Answer 6

above chance guessing of stimuli in scotoma (visual field deficit area) while reporting no awareness i.e. blindness in that region.

Question 7

How does blind sight relate to the subjective and objective conscioussness treshhold?

Answer 7

Stimulus below subjective but above objective threshold

Question 8

What causes the phenomena of blindsight?

Answer 8

Caused by damage to V1 -> causing blind spot.

LGN projections to extrastriate visual cortex explaining why there is information present still in brain (seen on fMRI activity)

Question 9

What does the phenomena of blindsight suggest for the neural correlates of visual conscioussness?

Answer 9

That V1 representation of a visual stimuli is necessary for conscious expierence of that stimuli

Question 10

What is Binocular Rivarly? How is it experimentally demonstrated?

Answer 10

(typically) Use of colour glasses in order to present one stimuli to one and another to the eye at the same time.

The stimuli do not fuse together in perception but alternatingly indivudally perceived.

Question 11

What do fMRI studies of binocular rivarly show?

Answer 11

fMRI shows that at points in time where stimuli 1 is perceived (based on report) the brain area coding for that kind of stimulus is more active wheras when Stimulus 2 is percieved the he brain area coding for that kind of stimulus is more active. F.e. When the face is perceived the FFA is more active.

Question 12

Name the 6 “models of neural mechanisms of consciousness” discussed in the lecture

Answer 12

1. Microconscioussness
2. Level of activation
3. Higehr Stages of Visual Processing
4. Ventral vs. dorsal Pathway
5. Recurrent Processing
6. Global Workspace Theory

Question 13

What is the key claim of the theory of Microconscioussness?

Answer 13

Selective activation of brain area specialized in a feature representation is sufficient for awareness of those contents

Question 14

What is one argument for and one against the theory of Microconscioussness?

Answer 14

Pro: Binocular Rivalry (selective activation of corresponding higher order visual areas when stimulus is perceived, f.e. FFA when face is perceived)
Con: Would FFA in a petri dish be sufficient for conscioussness? Intuition no. Theory (kind of) has to say yes.

Question 15

What emprical evidence supports the “level activation” theory of conscioussness?

Answer 15

Whereas V1 is always active, corresponding brain areas increase activity correlating to stimuli salience.

Question 16

What emprical evidence supports the “Higher Stages of Visual Processing” theory of conscioussness?

Answer 16

Only 20% of cells V1/V2 differentially respond to different stimuli, but 90% of higher order areas (in monkeys of course)

Thus: consciousness depends on higher order stages of visual processing

Question 17

What function does the ventral and dorsal pathway refer to? What is the difference between the 2?

Answer 17

Ventral -> What (object recognition)
Dorsal -> Where/How

Question 18

Which visual pathway is associated with Conscioussness and why?

Answer 18

The Ventral Pathway (“What”) is assosciated with conscious perception. Lesion studies in humans show that damage to the ventral pathway leaves interaction ability with external stimuli intact, but leads to inabiality of recognition.

Question 19

What is recurrent processing?

Answer 19

Recurrent processing = feedforward + feed backward + horizontal processing

Question 20

What is the Global Workspace Theory? What, according to GWT is necessary according for conscious experience of a stimuli?

Answer 20

Activation of peripheral areas by stimuli not enough. Only If stimuli is available for processing by many areas in the brain is it conscious. “Brain wide Fame” is the necessary condition for conscious experience.

Question 21

Name one argument for and one against the GWT.

Answer 21

Evidence: Masked words activate only peripheral regions like OC, whereas visible words activate brain wide networks. Mased words are not conscious wheras visible ones are.

Problem: yet no evidence that the other activated areas (i.e. more central, and those recruited into the global workspace) have information about the stimulus. Could be just unspecified activity.