Where the target you are looking for has a specific feature that makes it "pop-out" in the display
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What is a conjunctive search?
Where the target you are looking for doesn't have one specific feature that makes it stand out but shares its features w other items in the display - only one to have the conjunction of features
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Which one is harder?
Conjunctive
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Treisman (1988, 1992) - what theory?
Feature Integration Theory
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Basis of FIT?
That features of objects (size, shape, etc.) are separable from the objects themselves
Rapid initial parallel process to identify features / large differences noticed
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What happens in Focused Attention stage?
Slower, serial process to form objects from combining features - requires attention to 'glue' the features together - feature combination can be influenced by prior knowledge
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Evidence for FIT:
"pop-out" not affected by no. of distractors / illusory conjunctions
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What are illusory conjunctions?
Where you haven't glued features together in the pre attentive stage so you get illusory conjunctions (of features)
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When do illusory conjunctions occur?
when focused attention is absent / relevant stored knowledge is absent / spatial attention is diverted (CAN HAPPEN ACROSS SPACE NOT TIME)
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Evidence against FIT:
Duncan and Humphreys (1989) / Negative-priming tasks (Tipper, 1985)
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Duncan & Humphreys (1989) - What?
Found finding target 'L' was harder when T (distractor) was rotated 180 or 270 degrees vs 0 & 90 (FIT can't explain as both conjunctive searches)
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How do they explain their results?
D&H say it can be explained in terms of how similar the distractors are / easiness to group objects together
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What do negative priming tasks show evidence of?
Show evidence for semantic processing of unattended stimuli (FIT says attention is required for this)
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Wolfe (1998) - what theory?
Guided Search theory / Dual-Path model
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What is it?
instead of assuming initial f. pro is parallel and subsequent pro is serial - Wolfe assumes a mix of serial & parallel strategies are used for visual searches
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What is the activation map?
Places in a scene have different activations depending on their relevance - places w/ highest activation gets attention first
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Ehinger et al., (2009) - what?
Recorded eye fixations nd found observers fixated to relevant parts of the scene early on - told to look for people, ignored the sky and other parts due to prior knowledge
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Posner's attentional systems - what are they?
Endogenous System / Exogenous System
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Endogenous system - what?
Top-down, goal driven // controlled by ind's intentions & expectations - involved when informative, central cues are presented
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Exogenous system - what?
Bottom-up, stimulus driven // automatically shifts attention, involved when uninformative peripheral cues are presented - salient or different stimuli most likely to be attended
Patient RM - 2 strokes - damaged large areas of bilateral occipito-parietal cortex / unable to focus attention one +1 object or switch attention / had severe feature binding issues
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Patient RM's feature binding issues - time?
Made illusory conjunction errors even when showed image for 10 secs / healthy brain only makes these when shown for 1
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Parietal lesions can cause binding problems across _ _ _ _ _ but not _ _ _ _?
space / time
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What findings demonstrate parietal lobe importance for spatial attention?
Neuropsychological findings
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Where in the brain are lesions also associated w/ impaired feature binding?
Thalamus lesions
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Binding problem - what?
How are different features of an object bound together (Temporal coding)
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C. Von der Malsburg (1981) - what hypothesis?
Temporal correlation hypothesis
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Singer and Gray (1995) - what?
Suggested that gamma oscillations might be relevant for binding by temporal synchrony / some EEG studies found enhanced gamma oscillations in conditions that require more binding & spatial attention
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Other cards in this set
Card 2
Front
What is a feature search?
Back
Where the target you are looking for has a specific feature that makes it "pop-out" in the display
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