Week 5: Attention 1 & 2 Flashcards
Definition of Attention:
1. Sustained Attention (Alertness)
Related to psychological arousal (continuum from drowsy, inattentive to alert, attentive)
Problem of vigilance: performance declines over a long watch (radar operators, quality control inspectors)
Definition of Attention:
2. Selective Attention
Limited in the number of stimuli we can process
Attend to one stimulus at the expense of others
People as limited capacity systems: don’t treat all stimuli equally
“The Cocktail Party Problem”
Cherry (1953)
How do we follow a conversation in a crowded environment?
- Can “pick out” one conversation from background
- “Picking out:” processes take sound energy at ear, translate to understanding
- Translation is selective (stimuli not all treated equally)
To study this process: Dichotic Listening and Shadowing
Dichotic Listening and Shadowing task:
details and results
2 channel: sensory pathway acting as a source of information
Attended vs unattended:
Shadow Message 1, then ask about contents of Message 2
Results
Unattended Channel:
No memory for unattended message
Switch from English to German: not noticed
Switch from male to female: noticed
Reversed speech: “something queer”
Switch from voice to 400 cps pure tone: noticed
Dichotic Listening and Shadowing task:
Cherry 1953:
Conclusions
Only superficial (physical) features perceived
(things distinguishing voice, non-voice, or male, female)
Semantic content not analysed (language, meaning)
Pre-attentive processes vs. focal attention
Neisser, 1967
Sensory (physical) features processed pre-attentively
Meaning requires focal attention
Plausible: aware of unattended stimuli only superficially
Cherry’s version of
How Do We Select the Attended Message
Binaural presentation (Cherry): both ears receive both messages, same voice, differ only in content
Very difficult!
Source localisation in space important cue (phase differences in arrival times at ear)
Criticism of Cherry (3)
looked at what is remembered but we want what is perceived.
Confounds: perception and memory
Might be perceived then forgotten?
Filter Theory (Broadbent, 1958)
Attention acts as a filter to select stimuli for further processing
S10
Due to this limited capacity, a selective filter is needed for information processing.
All stimuli are processed initially for basic physical properties.
based on physical properties, the selective filter allows for certain stimuli to pass through the filter for further processing, while unattended stimuli will be filtered out and lost
splitting of incoming stimuli to attended or unattended channels
Filter Theory (Broadbent, 1958) Procedure and Process
Meaning extracted in limited capacity channel
Filter precedes channel, protects it from overload
All stimuli stored briefly in short term store (STS)
Raw acoustic trace, decays quickly if not selected
Evidence for Filter Theory
Split-Span Experiment:
Details and Results
Interaction of short term store and filter
Dichotic digit stream:
Temporal order: 3-4 correct Ear-by-ear recall: 6 correct
Prefer stating one side before the other
Evidence for Filter Theory
Split-Span Experiment:
Theoretical stuff
Ear-by-ear recall needs 1 filter switch
5 switches needed to follow temporal order
Thus EBE > Temporal correctness
Switches take time, Short term store trace decays
The Failure of Filter Theory:
“Dear Aunt Jane” experiment
(Gray & Wedderburn, 1960)
Split-span experiment with meaningful material
Preferred recall follows semantic context, not presentation ear
The Failure of Filter Theory:
Moray (1959)
Person’s own name often detected on unattended channel
Selection based on meaning not consistent with idea that meaning only extracted on the attended channel
The Early vs. Late Selection Debate
Early: Treisman 1961
Late (Deutsch^2, 1963; Norman 1968)
Disagreement about location and properties of filter
Early: Treisman 1961 1) Sensory Analysis 2) Filter 3) Semantic Analysis (LTM) => Report
Late: (Deutsch^2, 1963; Norman 1968) 1) Sensory Analysis 2) Semantic Analysis (LTM) 3) Filter => Report
Attenuation Model (Treisman, 1961)
attended and unattended both pass through the filter.
unattended partly blocked (attenuates)
Filter biased by context, message salience
Highly salient stimuli (name), semantically related material (Dear Aunt Jane) gets through filter, shifts attention
Evidence for Early Selection
Treisman & Geffen (1967)
Shadow and ignore channel:
tap sound
% correct detections higher on shadowed channel, but not zero on unattended channel
Consistent with filter that attenuates stimuli instead of blocking them
Criticism of Early Selection
Complexity of filter: Needs to respond to semantic context, distinguish related from unrelated stimuli – simpler alternative?
Late Selection
Bottom-up and top-down selection mechanisms
Bottom-up, stimulus driven and top-down, selection by “pertinence” (relevance to task)
Need both kinds of activation to get through filter, otherwise decays
Early Selection VS Late Selection
agreements and differences
ES and LS theories agree recognition needs (a) encoding, (b) access to LTM
LS theory: All stimuli access LTM, not sufficient for awareness
ES theory: LTM activation = conscious awareness
LS theory: need to pass filter for awareness
Evidence for Late Selection
McKay (1973)
Semantic processing on unattended channel
Recognition biased by previous shadowing task
Shadow: “They threw stones towards the bank” (ambiguous) Ignore: “ ... ... ... ... ... river” or “ ... ... ... ... ... money” Recognition: “They threw stones towards ...” (1) “...the side of the river” (2) “... the savings and loan”
Evidence for Late Selection
Von Wright, Anderson & Stenman (1975)
Classical condition GSR to target words (word+shock)
In shadowing task:
in ignore channel activate have word
Semantic activation in the absence of attention (word result to GSR)
Generalised to other words in category
