Sensation and Perception: Attention

Study Notes

Attention is preferentially processing some stimuli at the cost of processing other parts
Helps to perceive the attended stimuli better than the rest of the objects
Needed because the perceptual system has a limited capacity and cannot process everything in the visual scene simultaneously

Overt attention: involves looking directly at an object
Covert attention: involves looking at one object but attending to another object

Unless you purposely try not to, you tend to fixate the object to which you attend
Fixate is when someone looks at an object
What you fixate on depends on your goals and expectations
Saccades are the ballistic eye movements between these fixations
During saccades, you become temporarily blind

Two processes:
- Initial involuntary process: mediated by attentional capture (e.g., sudden change on TV)
- Subsequent voluntary process: guided by goals and expectations

Determined by the salience of an image or object
Salience is the quality of being noticeable
What captures our attention:
- High contrast (colour, luminance, size, orientation, motion/flicker)
- Fixations are not only determined by goals but also expectations

Different aspects of a stimulus are processed independently in separate brain areas
Issue of how an object's individual features are combined to create a coherent percept
Feature integration theory (FIT):
- Suggests that this problem is solved by attending to only one location at a time
- Features associated with that location are processed and bound together
- Avoids binding features from different objects
Illusory conjunctions: predicts that if attention is inhibited, features from different objects will be incorrectly bound
Balint's syndrome: a patient with parietal lobe damage is prone to experiencing illusory conjunctions

Some form of visual search is required for binding to occur
Conjunction search: target object contains the same features as distractors
FIT suggests that undivided attention is needed to understand each object's integration, making conjunction search slow
Feature search: finding a target object with a unique feature that distractors don't have, making it faster

Attention determines what we remember
We can only remember a part of the scene at a time
If part of the scene changes, we may not notice it if attention is not drawn to the location of change