Selective Attention 1

What did William James (1890 say about attention?

“Everyone knows what attention is. It is the taking of possession by the mind, in clear and vivid form, of one of what seem several simultaneously possible objects or trains of thought

What is selection?

prioritisation of a subset of info

Why do we need selection? (3)

brain receives info from multiple sensory systems

not all of info is relevant at any 1 time

physiological limits imposed by effector systems sa eyes and hands

What are capacity limits associated with?

neural function and metabolism (<= 10% cortical neurons spike at any one time; Lennie, 2003)

What does the physiology of the visual system do?

imposes constraints on the type and amount of info observers obtain from the env/scene

What does the gradient of visual acuity determine?

the spatial resolution of info sampled in a single fixation

What does covert attention do?

prioritises areas (objects) for action sa eye movements

prioritises info for analyses and retention

What are post perceptual processes?

working memory

capacity limited temporal stores such as verbal STM (7 ± 2) and visual WM (<=  4)

What is the accuracy of recall determined by?

capacity/load

decay function (exponential)

selective attention gates access to VWM (reduces load)

What does attention enhance?

accuracy of recall for selected card

What does selective attention protect?

capacity limits in terms of our effectors systems (action) and cognitive systems (e.g. VWM) and cortical computation

What does selection bias?

perceptual sampling (where do we look) and post perceptual processes (what do we encode)

What can attentional guidance be?

exogenous - bottom up

endogenous - top down

What is exogenous attention?

stimulus driven capture of attention by salient signal sa bright flash

involuntary - attention is captured by non-predictive cue

fast rise time - peak benefit around 150 ms after cue onset

inv inhibition of return

What is endogenous attention?

goal driven selection with a slow rise time

peak benefit around 275-400ms after cue onset

long lasting bias - no IOR

What type of concept is selective attention?

cognitive construct used to explain behaviour and is not directly measurable

What do psychologists do to measure attention?

manipulate stimuli and measure changes in behavioural/physiological responses to make inferences abt selective attention

What did Montagna et al (2009) do?

investigated the effects of ex. and end. cues on spatial acuity

What did Montagna et al. (2009) find?

if shifts of attention are used to allocate limited capacity at perceptual resources - spatial acuity at cued locations should be more than uncued baseline and SA at uncued locations shld be less than uncued baseline

What was found abt spatial acuity at cued location? (2)

significantly higher than uncued baseline

concomitant decrease in acuity at uncued location

What does covert attention mediate?

changes in observer’s spatial acuity in absence of eye movements

What are objects outside the lab often accompanied by?

noise - occluding objects in visual scenes and competing voices in auditory scenes

What did Dosher and Lu investigate?

whether attention includes a noise-exclusion mechanism

What was found abt discriminability of targets?

higher at cued locations than uncued

When was the affect of cueing more pronounced?

in displays containing high levels of external noise

What does selective attention increase?

detection at cued location by increasing signal to noise ratio

What did Spence and Driver investigate?

benefits of auditory spatial attention using an orthogonal cueing paradigm

What does selective auditory attention increase?

increases spatial acuity of auditory localisation and acuity of non spatial judgements (pitch)

What does selective auditory attention protect?

protects selected items from degradation in auditory working memory

What do ex. and end. cues do?

produce similar benefits but have different time course

What is selective attention?

a set of processes that protect capacity limited perceptual and post perceptual resources

What does covert spatial attention increase?

spatial resolution and signal to noise ratio

What does covert spatial attention combine?

sensory info across modalities