Selective Attention Flashcards
What is Selective Attention?
Refers to the processes that allow an individual to select and focus on input for further processing while simultaneously suppressing irrelevant or distracting information
Dichotic listening Cherry (1953)
The process of receiving different auditory messages presented simultaneously to each ear. Listeners experience two streams of sound, each localised at the ear to which it is presented and can focus on the message from one ear while ignoring the message from the other ear.
The participants were asked about the semantic content of the ‘unattended’ message
- They didn’t notice if the language changed from English to German or if the speech was reversed
- They could report the gender of the speaker and whether the message contained speech or non-speech
Conclusions
- People process ‘unattended’ information only to the level of physical features
- No semantic information is available from the unattended message
Early selection model Broadbent (1958)
- Filtering occurs at an early stage of analysis (prior to meaning)
- Brain filters out any message not having appropriate ‘physical’ characteristics
The early selection model of attention posits that stimuli are filtered or selected to be attended to, at an early stage during processing
A filter can be regarded as the selector of relevant information based on basic features such as colour, pitch, or direction of stimuli
Gray & Wedderburn (1960) Split-span experiment
A test in which brief auditory messages in the form of two different lists of digits or words are presented rapidly and simultaneously, one list to each ear
Participants are required to report as many digits or words as possible in any order
Broadbent suggested that attention was based on physical characteristics of sensory channels.
Gray & Wedderburn (1960) suggested that the unattended message might also be processed for its meaning. In their experiment, one word presented so that different syllables were presented alternately to different ears. At the same time, another word is decomposed in a similar way and presented to the other ear.
- 40% reported by ear
- 60% reported by meaning
- So, it seemed like the unattended message was processed for content (60% reported by meaning)
This shows that the unattended message can be processed for its meaning.
Corteen & Dunn (1974)
- City names paired with electric shock
- Subjects sweat when they hear a city name
- Test: focus on one ear and ignore the other
- Press a button if you hear a city name in either ear
Measures: GSRs (galvanic skin responses) and button presses to city names
Results:
- 42% of city names in unattended ear elicit a GSR (30% for non-shock associated city names)
- On only 2% of these trials did the participant make a button press response
- Different measures of awareness of unattended stimuli give different results
Attenuator model Triesman (1964)
Unattended information is ‘attenuated’, it is not filtered out completely
All inputs are analysed for meaning
- The dictionary analysis units act as the final filter
- Different words have different trigger thresholds
Neisser & Becklen (1975) selective looking
Subjects in a selective-looking paradigm attended to one of two visually superimposed videotaped ballgames by responding every time the ball was passed in a target game. An unexpected, yet highly visually conspicuous, event, occurring about halfway through the 1-rain game sequence, was noticed by only 18 out of 85 subjects.
Simons & Chabris (1999)
- Around 50% of people fail to notice the gorilla when attending to the team in white T-shirts
- More likely to notice gorilla if attending to team in black T-shirts
Perceptual load theory Lavie, (1995)
- Perceptual system has a limited capacity
- All stimuli are processed automatically until capacity is reached
Perceptual load does not just affect distraction by irrelevant stimuli; it also affects individuals’ subjective awareness of such stimuli.
High perceptual load induces inattentional blindness (people fail to notice easily visible stimuli)
Low perceptual load leaves ‘spare’ capacity, resulting in full perceptual awareness for both relevant and irrelevant information
Rees, Frith & Lavie (1997)
Psychophysics: longer motion aftereffect under low load than under high load
fMRI: more activity in the cortical area V5 (‘motion area’) under low (vs. high) load
What is the problem with video tasks?
Eye movements related to attended events might reduce acuity for unattended events
