Lecture 4 Attenion Flashcards
What is a conjunction target and does it pop out
Conjunction targets have a combo if features. Don’t pop out
So RTs increase linearly with display size
Slope twice as steep for target absent trials.
Bc SERIAL SEARCH
Pop out effects with letter stimuli?
Pop out only when target can be identified by a single feature
(Straight lines above curves…eg)
No pop out if it’s conjunctive
What is feature integration theory.
FIT
Treisman & gelade
Claims that role of intentional spotlight is to bind individual features of the object into coherent perceptual holes.
We see all the features first, in preattentive stage, with every feature being analysed in a different area of brain - in its own FEATURE MAP
Focussed attention binds them all together into an object
Conjunction targets require feature binding - so need focussed attention - leads to sea rial search
Limitations of FIT.
Feature integration theory
FIT isn’t really good at predicting what will pop out and what won’t. Can have 3 features that create 3Dness…. Which actually gives directionality causing one to pop out
What did wolfe say about search theories?
That it’s better to describe it as inefficient and efficient searches..
Since not all tasks are either serial or parallel searches
And sometimes the increase in RT of serial searches doesn’t increase linearly with display size…. Plateaus
And parallel search functions aren’t always completely flat… Some detectable increase
What is wolfe’s guided search theory?????
Two stage theory
Initial parallel stage provides a candidate list of possible targets.
Second serial stage checks candidate list for targets
Similar targets and distractions lead to a large candidate list and inefficient search!!!
So small candidate list = efficient search!!!!
What is the stroop effect?
When asked to name the colour of the ink that a word is written in, people are slow when the word doesn’t match the ink colour
Parallel processing of colour naming and word reading
Bc word reading is fast and involuntary - word is available before colour name - creates output interference
Colour naming slow and controlled
Asymmetrical - if you swap the task around, no interference
What did the controlled and automatic processing study by shiffrin and Schneider find
Told to search for digit targets in arrays of distract or letters in rapid sequences
Conditions
Consistent mapping - targets and distract were distinct, either numbers or letters
Varied mapping - targets and distractors were varied
Performance for CW became automatic with practice, accuracy increase, became independent of memory set and display size
Never happened with VM
What is the Erikson flanker task
Asked to report identity of the central character in linear array of characters
3 conditions - compatible, neutral and incompatible
Slower in incompatible condition bc flankers distract
Implies some parallel processing of conjunction stimuli
Failure of focussed attention bc everything under spotlight is processed
Decreases with spatial separation- effect disappears at 1-1.5 degrees of visual angle - gives estimate of spotlight size
What is their attentional blink
Rapid serial visual presentation (RSVP)
Present stimuli in rapid succession.
Hard bc presenting stimuli in the me location of visual display
Usually info will stay in iconic memory, but if u put another image there, it will mask it
2 targets: report white letter, and detect if there was an X
Detecting th second target is worse when it’s a few Frames after the first target, but gets better as the gap between the two gets larger
- this is the attentional blink
Only happens when you need to look for 2 targets
What’s welfords single channel theory
That were only able to make a decision about one stimulus at a time
Decision making take time - creates bottleneck
Don’t process all stimuli equally as we can reject no targets rapidly in parallel without extended processing
And to identify target, need to grab from stimulus stream, and for, stable mental representation
Makes us temporarily insensitive to other targets
Does mean RT increase with display size for pop out targets?
No
Parallel search for targets - no cost for adding more items
Might take you longer to say that there are no targets..
