TASK 5 - CONSCIOUSNESS + ATTENTION Flashcards
Lamme’s theory
= there are 2 selective phenomena
- conscious experience
- attention
Lamme’s theory
1. selective conscious experiences
= we are not aware of everything
- we are aware of whatever is in the focus of attention
- -> based on theoretical + neurobiological grounds
Lamme’s theory
2. selective attention
= some sensory input is processed faster + deeper and becomes more readily available
change blindness study
- we have limited conscious representation of outside world –> selective process in which some items in a scene are privileged over others
1)
2)
3)
psychological arguments
- Lamme’s theory A
= when many sensory inputs reach brain, attention allows only some to reach conscious state
- once something has reached conscious state –> possible to generate conscious report
- 2 levels of processing: attended + unattended
ATTENTED –> CONSCIOUS –> CONSCIOUS REPORT
- BUT, many stimuli activate neurones + sensory processing does not necessarily complete to perceptual stage
psychological arguments
- Lamme’s theory B
= same as A + addition of unconscious processing
- 3 levels of processing: attended + unattended + unconscious
ATTENDED –> CONSCIOUS –> CONSCIOUS REPORT
- BUT, suggest no difference between attended and conscious stimuli –> identical
psychological arguments
- Lamme’s theory C
= eliminates conscious step –> equating conscious to attended
ATTENDED –> CONSCIOUS REPORT
psychological arguments
- Lamme’s theory D
= attention determines whether conscious report about stimuli is possible + whether items are stored in sufficiently stable manner (in WM) to allow report at later time and comparison with other scenes
- attention does NOT determine whether stimuli reach conscious stimuli
- distinguish conscious and unconscious inputs earlier in process
CONSCIOUS –> ATTENDED –> CONSCIOUS REPORT
Lamme’s theory D
- support
- CB + IB are not failures of consciousness but failures of conscious memory
- cue works also long after the item has disappeared –> representation still present and attention can select from it (after onset of stimulus 2 cueing doesn’t help anymore thus by then presentation has vanished)
- -> THUS, there exists a short-live, vulnerable + not easily reportable form of visual experience (phenomenal awareness), which contrasts with a more stable, reportable form of awareness (= access awareness)
- attentional selection is independent of either awareness or memory, but determines whether we go from phenomenal to access awareness
Lamme’s theory
- neuroscience arguments
- attention induces increased selective neuronal activity, making processing faster, better and deeper
- exogenous attention: salient stimuli are processed more efficiently (comes from genetics + visual experience)
- saliency reflects how long-term memory has shaped + modified sensory processing
- priming may influence this by leaving a trace
- endogenous attention: brain parts that extract the meaning of a cue + relate it to current goals pre-activate sensory pathways
- combination of sensory processing with short- + long-term memory explains why a particular brain, at a particular moment in time, is inclined to favour one stimulus over another
- can imagine this to occur without phenomenal experience so attention isn’t a priori associated with visual awareness
mechanisms of phenomenal experience
1. feedforward sweep
= FFS = successive activation of cells in a cortical hierarchy
- visual processing mediated by the FFS, however sophisticated, is not accompanied by visual awareness (= unconscious)
- purely unconscious activation still results in priming + adaption –> memory + awareness are different phenomena but share neural mechanisms
mechanisms of phenomenal experience
2. recurrent processing
= RP = as soon as the FFS has reached an area, recurrent interactions btw neurons within that area can start
- necessary for visual awareness to arise (= conscious)
- depending on the extent to which recurrent interactions btw visual areas incorporate interactions with action/memory-related areas, awareness evolves from phenomenal to access awareness
- whether this occurs depends on attentional selection mechanisms that influence FFS + RP
- other mechanisms determine whether neurons will engage in recurrent interactions at all
- -> THUS whether processing goes from unconscious to conscious
process of phenomenal experience
- if multiple stimuli are presented, these are all represented at the early stages of FFS
- at successively higher stages, receptive fields become larger + larger so that competition starts to arise (results in crowding)
- attentional selection resolves this competition
- only a few stimuli reach highest levels (incl. executive space)
- meanwhile the early visual areas have started recurrent interactions –> features are related + bound to each other –> phenomenal awareness
- since there is little competition at low levels, multiple stimuli can be represented
- can have phenomenal awareness of many items in a scene - when these recurrent interactions grow more widespread + eventually include executive space, the visual info is put into context of the systems current needs + goals –> access awareness
- due to attentional selection, only some recurrent groups get there
- awareness is limited to a few items in the scene
process of phenomenal experience
- support
- backward masking makes initial stimulus invisible –> still evokes FFS but RP is suppressed
- TMS over MT induces motion sensations, only when V1 isn’t disrupted at a later moment in time –> feedback to V1 is necessary for motion awareness
- anaesthetised animals still have FFS but not RP
- figure-ground detection task: when seen –> RP; when not –> only FFS
Watanabe study
- visual awareness + top-down attention are thought to be 2 distinct processes:
1. top-down attention directed to invisible stimuli leads to priming
2. gist of scene can be perceived despite near absence of attention - can’t say how they are neutrally dissociated in the visual system, which is what they are trying to do with this weird god damn experiment I don’t actually understand
