Chapter 6: Visual Attention Flashcards
Define Attention. What are two types of attention?
Attention is the process which results in certain sensory information being selectively processed over other information.
Two Types:
1. Overt Attention: When you move your eyes from one place to another to focus on a particular object or location.
- Covert Attention: when you shift your attention without moving your eyes.
What did Cherry and Broadbent’s selective listening experiment find?
They found that in dichotic listening, we can only attend to one ear at a time. BUT while we can repeat the message from the attended ear, we can often describe some characteristics of the stimuli from the unattended ear.
What is Broadbent’s theory of attention?
A stimuli enters –> Sensory Memory –> Filter (only attended information moves forward) –> detector –> memory.
What is spatial attention and what is it often compared to?
Spatial attention is attending to a specific location
It is often compared to a spotlight that scans a scene.
Describe Treisman’s Feature integration Theory.
This is when we combine features from multiple stimuli.
It starts with an object (stimulus) that enters our preattentive stage where we break it down and separate the features. Then in focused attention, we combine the features back together and this forms our perception.
What are two types of visual search?
Visual search is looking for an object among objects.
- Feature search is being able to find an object based on a single feature. (e.g. a black cat among tabby cats)
- Conjuction search: searching for a combination of features to find an object. (e.g. a long haired black cat among short and long haired tabby and black cats)
What happens when we scan a scene by moving our eyes?
Scanning is important because the best vision occurs at the centre of the visual field. When scanning, our eyes move in a combination of fixations (pauses) and saccades.
What is Corollary Discharge theory?
It is a theory that explains how we are able to see a stationary, unblurred scene when we are moving our eyes.
What are the three neural signals assocaited with eye movement.
- The Motor signal: the signal sent from the brain to the eye muscles
- the corollary discharge signal (CDS): a copy of the motor signal that occurs whenever the motor signal occurs
- Image Displacement Signal (IDS): Occurs when an image moves across the retina
What is the comparator and what rule does it use.
The comparator is the centre of the corollary Discharge signal. It operates by the following rule:
When ONLY the CDS or IDS reaches the comparator, movement is perceived but when BOTH CDS and IDS reach the comparator, no movement is perceived.
It is not a single area but multiple structures that work together.
How does corollary Discharge Theory Work?
- A motor signal is sent from the motor area to the eye muscles.
- The corollary discharge signal (CDS) is sent to the comparator.
- The eye moeves in response to the motor signal which causes the image to move across the retina. This generates an image displacement signal (IDS) which travels from the eye to the comparator where it meets the CDS
- When the IDS and CDS meet, the comparator inhibits the perception of the smeared image on the retina caused by the movement of the eye.
How does corollary Discharge theory stop our vision from being a series of snapshots?
Corollary discharge theory uses predictive remapping of attention to keep our vision from appearing as snapshots while it is inhibiting the perception of blurred motion.
Predictive remapping of attention is when we shift our attention to a target just before the eye begins moving towards it. This results in the snapshots being perceived as a coherent scene
What are four things that can influence visual scanning?
- Visual Salience: How much it stands out from the background. Attentional captures are when a stimulus grabs our attention without us meaning for it. Sudden movements are often Attentional captures.
- Interests and Goals: our attention is drawn to areas that have meaning to us, how we scan is affected by what we are looking for.
- Schemas: we will pay more attention to things we find unexpected and that don’t fit our schema.
- Task Demands: our scanning is affected by our current task and actions.
How does attention affect appearance?
attended objects are perceived as bigger, faster, ad more richly coloured. Attention makes objects appear clearer and more vivid.
What is inattentional blindness?
Being unaware of a visible stimuli because we are paying attention to something else.
