capacity and multitasking Flashcards
what are several limits to cognitive capacity?
what are they exacerbated by?
all processes take time
limits to input any one process
storage capacity limited
exacerbated when resources must be shared between tasks (multi-tasking)
what is multi-tasking?
what does it result in and why?
when we try to do tasks simultaneously
there is competition for shared resources - dual-task interference
what processes are involved when we try and switch between tasks?
task-switching costs
retroactive and prospective memory
executive control (planning and problem-solving)
describe the findings on drinking and using phone while driving?
mobile either hand held or hands free : slower reactions and more collisions - 4x more likely
alcohol : more aggressive driving e.g harder braking
why is the effect on driving of talking on phone or talking to a passenger different?
passenger sensitive to driver’s load (stop talking or wait for reply)
passengers help spot hazards etc.
how to measure dual task interference in a lab?
measure performance on conditions separately and then when combined
what are the 3 sources of dual-task interference?
- competition for using the same sensory or effector system e.g parts of body or brain or if use same ‘module’ in the brain
- competition for use of generic central processor
- limited capacity of executive control mechanisms so competition for specific resources including this executive control
describe evidence for competition for domain-specific resources as a source of dual-task interference?
2 continuous speech inputs can’t be simultaneously understood or repeated
performing spatial tracking task interferes with use of visual imagery to remember stuff (both use visuo-spatial working memory)
describe the general-purpose processor as viewed by Broadbent?
as a source of dual-task interference
needed to perform high level cognitive functions e.g decision-making
and seat of conscious awareness
describe the general-purpose resource pool of the generic central processor as a source of dual-task interference?
when will interference occur?
what changes the size of the pool?
energy shared among concurrent high-level processes
interference when increase difficulty of one task to reduce capacity available for other task
pool increases or shrinks during cognitive effort or fatigue
describe a case of demanding tasks combined without interference?
what does this dispute?
sight-read piano pieces (easy or hard) shadowed prose (easy or hard) - don't require same mdalities
performance in both not influenced by difficulty in the other condition
disputes idea that dual-task intereference is due to competition for use of general-purpose processing capacity as if one conditioner harder, should limit capacity and therefore reduce performance in other condition
why does phoning someone while driving interfere with driving performance?
require use of different input/output modalities
but both require construction of mental model especially if person asks driver to think about visuo-sptial array
describe the importance of practice in dual-task interference?
and why?
tasks which interfer when combined become easier to combine with practice to the point where no interference
why?
practice reduces need for executive control of the processes - automates it - so load diminishes to other functions
Broadbent’s argument about central processor?
central processor switches between 2 tasks
and while it services one task, input/output for other is stored
describe the effect of stimulus onset asynchrony (SOA)?
what is this known as?
if short intervals then response selection for stimulus has to wait until stimulus 1 response done
known as robust psychological refractory period even when in different modalities
