Video Module 9: Feature Integration Theory Flashcards
What is the “beam of attention”?
Attention is like a spotlight; we can focus it broadly or narrowly. The more narrowly we focus our attention, the more we pay attention to fine details.
Is expectation priming based on objects and features, or regions of space?
Both. Expectation priming relies on spatially based and object based attention.
What is spatial attention?
We can focus our attention to a particular region of our visual field. Additionally, we can move our attention from one region of our visual field to another, even without moving our eyes.
hemispatial neglect
in which patients with damage to the right parietal lobe tend to ignore stimuli on the contralesional side of space and are hyper oriented to the ipsilesional side.
-e.g. damage to the right parietal lobe causes patients to ignore their left side of their visual field
- evidence shows that participants may unconsciously register information from the neglected area
- hemispatial neglect provides evidence that our conscious attention relies on focusing on regions of space
- hemispatial neglect is an attentional deficit, not a perceptual one
What is object based attention?
We can focus our attention on specific objects, even if they occupy the same space.
- neurological evidence: differences in activation in the FFA vs. PPA when viewing a superimposed image of a face and a house and focusing on one or the other
- If attention were purely spatial, we wouldn’t be able to change our focus between the house and the face
feature integration theory
a proposed model which explains how we identify features and combine them to create perception
- Attention is the glue that combines the “what” (object info) and “where” (spatial info) systems of perception
- Theoretically, there are different regions of the brain focusing on each feature of an object
Proposes two different stages of attention:
1) Pre-attentive stage: we process visual sensory info
2) Focused attention stage: we combine features by focusing our attention
What is a feature search? What does it mean to say that it is automatic and parallel?
in which, in an array of objects, the target object is one which is defined by a single feature that it doesn’t share with any of the other objects
A feature search is automatic in that it is very easy for us to quickly identify the target. Increasing distractors (set size) does not increase the difficulty.
It is parallel in that we can process all of the objects at once and identify the target without much effort.
What is a conjunction search? What does it mean to say that it is effortful and serial?
in which, in an array of objects, the target object is one which shares a conjunction of features with the distractor objects.
A conjunction search is effortful because we must direct our attention around the display of objects until we find the target. Increasing the number of distractors (set size) typically increases the difficulty.
It is serial in that we can only examine one region of the array at a time, and we must actively direct our attention from one region to the next.
How do feature and conjunction searches relate to the idea of feature integration theory?
The influence of set size on conjunction search and not on feature search demonstrates that there may be a preattentive stage where we process features first. If what we’re looking for is defined by a distinctive feature, it is easy to identify it in the preattentive stage. If what we’re looking for is defined by a conjunction of features, then we must focus our attention.
Does focusing our attention require a trade-off?
Yes. Focusing our attention requires a trade-off in that if we focus our attention broadly, we can perceive many features at once; however, it’s difficult to combine features (distinguish which feature belongs with which point of input). If we focus our attention narrowly, we can then become aware of how features are combined. However, we must move our attention from one place to another, increasing the amount of time it takes for us to recognize an object.
