Attention

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Attention

Neuropsychological Evidence

Koch: conciousness can be seen as the outcome of competitions / alliances / cooperations between biased neurons

Lamme:

Objects in receptive fields compete for processing limited amount of neurons

Attention as guiding feed forward sweep of information

"Last Traces"

Weights of stored knowledge of the system (genetics, salience, needs)

Depression

Attentional Bias: Emotional Stroop: Take longer to name the colour of anxiety related words

Balint Syndrome

Damage to pariatal lobe

Unable to shift attention

Able to see only one thing at a time

Neglect

Attend only onle side of the visual field

Location Based

Half Plate is eaten

Object Based

Half Clock drawn

Stages of Perception

Attn for concious report? Yes!

Ennns & DiLollo:

Other Evidence

Flanker Effect (Shaffer and LaBerge)

Broadbent saves Treisman

Cat is not percieved - its primed, or it takes only minimal Att because of priming

It takes longer to decide ‘dog’ is an animal when surrounded by words of another category

Non attended words are processed - Att. not needed to join features

Re-Entrant Model of Processing

Evidence:

Observational

Masking effects

Enns& DiLollo: Masking: With four dots around -isn't expected

Attentional Blink

No awareness of secnd T if presented shortly after first

Neurological

Recurrent Processes are stopped

Top-Down: Hypothesis confirmation

Bottom-Up Parrallel: Generates highlevel Hyptothesis

DiLollos& Gisbrechts

Two-Stage Model

If the second customer chats to behind forgets what he came for (info overwritten)

RSVP: Epsiodic info morea easily overwritten

RSVP: If stim. replaced /decayed= nothing to attend to possible

While Stage 2 is engaged , made difficult later information cannot be processed, so has to remain at Stage 1

2. Serial (Attention) Processes to join Sem + Epi for concious report

1. Parallel processing of features (Identity (Semantic), Size. Location, Shape, Colour(Episodic)

Attn needed for Perception? No!

Negative effects of short term exporsure

Sperling (50ms)

Only Simple cues: not "attend to vowels "

3-4 letters from 12 when cued by after signal

If attended: Enter WM

->Iconic memory

Attention by simple cues: colour and position (tone cue)

Lamme

Phenomenal Conciousness

Attn to glue features into objects

More complex stimulus pop out

Flanker-Effect should not be possible: Words need binding - However Attn only only on middle word

Duncan + Humphreys: L+T (L should still pop-out)

Today: "Efficient Search"

POP-Out Effect

Parallel Search (no Attn)

No. of distractors play no role

If only single feature no Attn required

Target pops out

Serial Search (Attn)

Conjunction Search (Featrue binding is neccessary)

No. of Distrators plays role

Distractors

Distractors need Attn

Target

Doesn't pop out

Paralell search when target and distractors discriminated by single feature

Patient with pariatal damage wrongly binds features

"Preattentive" Processes vs. Focal Attn.

Binding Features (Inital Perception as "Soup of features")

Relation to conciousness

Naish: "Attention gives rise to concious processing"

Coltheart: A Masked Stimulus is fully processed but: Uniting episodic & Semantic required for consciousness

Koch: Attention as mechanism that could be modeled: No consciousess needed

We can proces the stiumulus but not be concious of it: no Access Concious

Modality dependent

Auditory

Visual

Forms

Situation Dependent

Location dependent

Unfocused

Devided

Sinlge

Zoom in / out

level of detail gets worse

Contious / vs. Partial

Object / Location based / Semtincs based

Attention tying together different modalities

Ventriloquism Effect

Firure / Ground selection

Can follow story ear to ear

Covert

By changig neural acitvy (shrinking / enancing receptive field)

Overt

By Eye Movements

Top Down (Goal Driven)

Visual Search

Bottom up (Stimulus Driven)

Orientation reaction

Genetic / Ecperience Depenent

Attention as LTM /learned system bias

Lamme: Stimulus driven: size, contras, movement etc

Information Processing Account

Non-concious Material: Stuff that we have no receptors for

Stages of Processing

Attention needed

So many things might be processed automatically to an even categoric level (Lamme)

Only if attended to, matrial can be selected for concious report

An attentional filter is constantly surveying input channels for important material

Attenion can be biased

Current Goals / needs

Salient Stuff

Many things are processed in parallel but not fully

Meaning rather than specific Epsisode

Several Modules are constantly processing input

Why / What for: Theorys

Attention several different functions

Attention for action:

Allports Berries:

We cannot pick more than 2 berries

Attn. fits possible actions

Attn for Binding

To enable for concious report

Coltheart

Evidence: When pushed in Sperling they report letters but no colours or loc.

Dorsal and Ventrals (What, Where) streams in visual processing

Patient DF: It has been suggested (Goodale and Milner)ventral system recognizes objects. Object Related! The dorsal system more in driving some action in relation to an object. Viewer Related

--> Attn joining two parallel proceses

Consious generelly only when Combining Semantic (general) and Epsisodic (detail)

Cross modal Binding

ventriloquism effect: sound seems to come from lips in front although speakers on side

To combine features

We need attention to combine features into objects

For Filtering

Late Filtering: Deutsch and Deutsch were wrong: Not Everything is processed fully

Bottleneck to protect serial procssor

To overcome limited number of neurons

Lamme / DeLollo

receptive fields of neurons of higher visual areas seem to "shrink" around biased stiumuls

Early Filtering: Broadbent

Not Completely

Treisman

What about unattn. Stim?

Attn can follow simple cues to shift

dont need much attn to be recog

Reason=Priming

Masking Evidence

Evett & Humphreys: Invisible Lion Primes Tiger

Shadowing Evidence

Neurological Evicence

Meaning Cues Corteen and Wood: Response to unattended "Shocked words"

Cocktail Party Effect

Meaning Cues: Little red riding h continued on the other ear even when shadowed

We do process meaning!

Evidence: ERPs

Brain Stem: Normal Signal. Cortical: less magnitudeattending away from a stimulus actually reduces the intensity of the signal in the brain

Attention for Attentuation (Turning Down a Signal)

Completely

Broadbents Filter Theory

Evidence

but remember if voice m/f

but echoic store: If short messages: remember last words

Broadbent: Dichotic Listening: Dont remember anything from unattended ear

We can only attend to one thing ("gate") at a time

Need to protect a serial processor overflow