Divided Attention Flashcards
Divided attention is also known as…
multi-tasking
Which variables play an important role in divided attention
~ task similarity
~ practice
~ task difficulty
Bourke et al.
(1996)
~ the harder the task, the more likely it will interfere with concurrent tasks
~ tasks differentially use the ‘central capacity’ resource (limited)
The PRP effect
Psychological refractory period (PRP)
~ the period between presentation of S2 and the beginning of its cognitive processing
(in relation to CP bottleneck)
~ shows limitation of processing/responding to multiple events
The bottleneck for central processing
~ if two tasks are performed shortly after each other, then the response for task 2 is longer
~ cognitive processing of task 2 can only occur once the cognitive processing from task one has finished
~ causes delays in reponses
Stimulus onset asynchrony
e.g. the time between stimuli appearing
Pashler and Christian (4 + date)
(1994)
~ response to task 2 (R2) was unimpaired, simply delayed
~ as soon as R1 has started, R2 selection can begin
~ demonstrated presence of PRP + bottleneck
~ evidence for limited capacity
Evidence for limited capacity
~ PRP data shows bottlenecking
~ bottlenecking is related to response selection
~ our central attention controls the selection of processes
~ therefore our central attention has a limited capacity
Segal and Fusella
(1970)
~ suggests multiple capacity resources
~ central resource too simple
~ demands placed on visual modality should not affect auditory modality (tested this)
Attentional blink (AB)
~ suggests informational encoding its limited by attentional resources
~ two target stimuli get shown after one another
~ is 2nd shown 200-500nm after 1st it gets blinked –> due to limited attentional capacity
Lag-1 sparing
In the AB model, when T2 immediately follows T1 both are remembered
Practice and automaticity
~ some limitations of multitasking can be overcome by practice –> responses become automated
~ automated responses start out being controlled processes
~ automation allows attention to be redistributed
Schneider + Shiffrin
(1977)
~ looked at ‘automatic’ vs ‘controlled’ processes
~ participants searched through items looking for target set amongst distractors
How did S and S manipulate the experiments?
Schneider + Shiffrin (1977)
~memory set size
~ frame size
~ mapping consistency (varied and consistent)
Varied mapping
the relationship of the stimulus to response mapping varies from trial to trial
e.g. the same stimulus has different responses
Consistent mapping
the response to the stimulus is consistent across extended periods of time/different tasks
What was the finding of mapping consistency?
extended consistent training is required in order to develop automatic processing
Effect of memory set size and frame size on reaction time
~ clear effect on controlled processing
~ no effect on automatic processing
~ effect was on reaction time
Load Theory of selective attention
Lavie (1995)
~ Selective attention is modulated by demands placed on finite capacity perceptual resources
~ links selective and resource aspects of attention
Lavie experiment
~ participant asked to identify letter next two signal shape (U or H) under two conditions
~ low load = identify when there is a blue object and don’t when there is a red object
~ heavy load = identify when there is a blue square or a red circle but not when there is a red square or a blue circle
Effect of the heavy load (Lavie experiment)
~ perceptual processes need to perform a connection identification task
~ an attention-demanding task
~ attention consumed by signal
Effect of the low load (Lavie experiment)
~ perceptual processes perform simple feature identification task = minimal demand on attentional resources
~ attention splits over to distractor (letter)
Lavie + early vs late selection
~ When attentional demands are low, late selection occurs (more processing)
~ When attentional demands are high, early selection occurs (more filtration)
