PSYC2050 - Wk7 Attention and Working Memory Flashcards
Why do we have an attentional blink and what does it tell is about cognitive capacities?
There is a hard limit
What is a switch cost ?
Time (and maybe error) cost when switching tasks
Where is task switching happening in the brain?
PFC
Explain the idea of “task set”?
Preparation to perform one task rather than another
what are two processes which may invoke a switch cost?
Establishing an appropriate task set; and disengaging an inappropriate set
How much was the severe switch cost observed by Jersild (1927)?
Up to several hundred ms
What is the purpose of AABB or AAABBB switch task designs?
match practice and fatigue over trials.
In task switching experiments, what happens if both stimuli and responses are different from each other?
There are small switch costs (eg. A number task alternated with a word task)
What happens to switch costs when a common stimulus configuration is used to determine the the task and response selection rule?
There is a major cost involved in switching between similar tasks and response cues
Do people occasionally forget what task is next and does that explain task switch costs? What do we see?
No, there is no evidence of occasional slow trials affecting switch. Instead a general slowing of the RT distribution
What did Rogers & Monsell find about switch cost over two days of trials? 3
Day 2 performance improved.
Large switch cost despite predictability and practice.
Similar difficulty for letter and digit tasks.
Does practice eliminate switch costs?
No
How does task difficultly affect switch cost? Why?
When switching from a hard task to an easy task there is greater cost. Harder to disengage from a more demanding task.
does preparation time reduce task switching costs?
Yes more time to prepare increased reaction speed.
Does task-cueing eliminate switch costs?
No, they are reduced but not eliminated.
How doe we know whether it is preparation time or delay from last trial which reduces switch cost? [3: design, findings, meaning]
Meiran (1996) varied cue-to-next-stimulus and last-response-to-cue interval. Short cue to stimulus interval led to large cost even when there was a long delay from the last trial. This implicates active preparation
What does active preparation involve?
Both disengaging the past task and engaging the coming task
Can preparation remove switch costs entirely?
No there is always a residual cost
Why are residual costs (in task switching) regarded as exogenous effects?
They are stimulus driven because you can’t do any decision-making for the next trial until the stimulus has been presented and identified.
How do theories various theories approach switch cost? 3
- The role of active preparation (endogenous)
- the role of interference effects from past task (disengagement)
- Whether exogenous factors play a role
What is disengagement theory?
The past task set interferes because it is not adequately disengaged.
Why is disengagement theory not correct?
Evidence showing the role of active preparation even when decay time is controlled.
What is the endogenous + exogenous theory (Rogers & Monsell)? 2
- Endogenous preparation requires time
2. Residual cost is explained by exogenous component of task set which is triggered only by suitable stimuli
What is the endogenous only theory of switch costs?
The residual cost only arises because people do not prepare adequately on every trial. There is no exogenous factor playing a role.
What is the best theory of task switch costs and why?
Endogenous + exogenous; even when endogenous factors are addressed the lab, the residual switch cost remains.
What is Kahneman’s capacity theory?
Over-learned tasks become more automatic and consume fewer resources