Chapter 1: Consciousness enters the lab

Question 1

What are characteristics of conscious access?

Answer 1

open (=vast potential) and selective (= depending on switch of attention → conscious of colors, scent, sound etc.

Question 2

What is a difference between potential consciousness and actual consciousness?

Answer 2

Potential consciousness is extremely vast, however, actual consciousness is limited - reduced to one conscious thought at a time

Question 3

Why actual consciousness is limited?

Answer 3

at any given time, a massive flow of sensory stimulation reaches our senses, but our conscious mind seems to gain access to only a very small amount of it

Question 4

How would you define pre-conscious?

Answer 4

accessible but not accessed, not necessarily unprocessed (you may unconsciously adjust your posture)

Question 5

What is Troxler fading illusion? How can you study it?

Answer 5

The pink dots on the screen -> optical illusion affecting visual perception -> when one fixates on a particular point for even a short period of time, an unchanging stimulus away from the fixation point will fade away and disappear

You can record discharges of neurons from different places in the brain during moments in which dots are seen vs unseen

Question 6

How would you describe the difference between conscious access and attention?

Answer 6

Attention is selective isolation of one of elements of the environment - it can operate (and operates) largely unconsciously!
Conscious acess makes us aware of selected information + and makes it reportable to others

Question 7

How would you describe the difference between conscious access and vigilance?

Answer 7

Vigilance is the level of excitement in cortical and thalamic netoworks (sleep-wake cycle) which supports conscious state, however does not guarantee consciousness per se.

Question 8

What is a difference between consciousness and sense of self?

Answer 8

Sense of self is often measured in mirror self recognition tests. However, those tests have significant restriction - may just be measuring the extent to which an organism has learned enough about its own body to develop expectations of what it looks like, and enough about mirrors to use them to compare expectation with reality.
Moreover, self knowledge seems not to be necessary for conscious perception (vibing at a concert)

Question 9

metacognition

Answer 9

capacity to think about one’s own mind -> the ‘‘I’’ appears in mind twice -> as perceiver and perceived!

Question 10

When does paradox of two ‘‘I’’ dissolves accroding to John Stuart Mill?

Answer 10

Paradox dissolves when the observing and the observed are encoded at different times or within different systems (word on tip of our tongue -> we know we should know)

Question 11

why is minimal contrast important?

Answer 11

because it enables treating conscious perception as an experimental variable that changes considerably even though the stimulus remains virtually constant (example: disappearing dots)

Question 11

minimal contrast

Answer 11

a pair of experimental situations that are minimally different but only one of which is consciously perceived

Question 12

Why concept of ‘‘frequency tagging’’ is important for rivarly studies?

Answer 12

each image is “tagged” by flickering at its own specific rhythm, measured with EEG

during rivarly, the two frequencies exclude each other → if one oscillation is strong, the other is weak

importantly! dependent on attention (no attention, no rivarly)

Question 13

What are main findings from binocular rivarly studies in monkeys (house and face stimuli)?

Answer 13

1) Monkeys saw alterations between face and house stimuli
2) Illusion was not present at earliest stages of visual processing (V1, V2 unaffected)
3) Higher regions of cortical hierarchy (IT, STS) -> most cells correlated with subjective awareness -> their discharge rate predicted which image was subjectively seen !

Question 14

What are main take-away messages from rivarly studies?

Answer 14

binocular illusions prove that visual image can be physically present in the eye and be processed by the brain but still suppressed from conscious experience; consciousness is not a matter of initial visual processing but a later stage, rivalry depends on attention

Question 15

attentional blink paradigm

Answer 15

illustrates temporal limitations of conscious perception

easy identification of T1, but failure to perceive T2 if it follows T1 in 250 - 350 ms time window

attention is still busy processing T1 so T2 is missed (psychological refractory period - processing delay due to attentional bottleneck)

Question 16

inattentional blindness

Answer 16

when people become so absorbed in what they are doing that they lose awareness of their surroundings (mental isolation so to speak) - gorilla study as example

Question 17

What is example of experimental design with inattentional blindness paradigm?

Answer 17

participants gaze at the center of a computer screen but are told to attend to the top side, because the letter will apear there; however, after some trials unexpected shape appears in the centre → 2/3 of participants fails to notice it

Question 18

change blindness

Answer 18

inability to detect that part of the picture has been erased → two versions of the picture are presented alternatively on the screen → people fail to notice the change

-> possible confound: may arise not from a lack of awareness but from an inability to compare the old scene with the new one (so more of a memory issue!)

Question 19

choice blindness

Answer 19

experiment: male subject is shown 2 cards with picture of female face and he needs to choose which one he prefers, experimenter swaps the cards then, participant ends up with the card he did not choose, 50% of participants don’t notice it

Question 20

masking

Answer 20

-> making image invisible by flashing a picture surrounded in time by other similar shapes that act as masks and prevent its conscious perception

-> masking needs to be brief (40 ms and below)

Question 21

What is the timing of consciously perceivable images (supraliminal)?

Answer 21

60 ms and above

Question 22

What is the threshold of conscious image presentation?

Answer 22

50 ms -> people have 50/50 chances of seeing the image

Question 23

What is take-away message related to masking?

Answer 23

masking reduces naming and memory abilities → thus subjective reports should be trusted (subjective invisibility → objective consequences)

Question 24

out-of-body experience

Answer 24

a person perceives the world as if from a location outside their physical body

subjective experience which cause is in the brain

• reported by some patients during surgery

Question 25

what area is responsible for out-of-body experience?

Answer 25

cortical region in the right temporoparietal junction, when impaired or electrically perturbed, repeatedly caused a sensation of out-of-body transportation

Question 26

why is temporoparietal junction responsible for out of body experience? what it so special about this region?

Answer 26

high-level zone where multiple signals converge: those arising from vision; from the somatosensory and kinesthetic systems (our brain’s map of bodily touch, muscular, and action signals); and from the vestibular system (the biological inertial platform, located in our inner ear, which monitors our head movements)