Alex: Attention Flashcards
What causes attentional blink?
How does it compare to the bottlenecking described by Duncan’s results when participants viewed 2 items simultaneously in one attentional space?
Attentional blink is caused by presentation of successive objects at a rapid speed. Because of our attentional bottleneck, we are only able to attend the first stimulus presented in quick succession and therefore don’t notice the second one.
Attentional blink can cause a performance decrement that is sufficiently larger than what Duncan found when participants were asked to attend 2 items simultaneously in the same space.
Salient distractors or exogenous cues are stimuli used in experiments to summon what type of attention?
Salient distractors or exogenous cues are stimuli used in experiments to summon bottom-up attention
How did Theeuwes find that using a circle of a distracting colour effected participants ability to attend to the orientation of a line in the diamond in the ‘colour distractor condition’ of their 2010 experiment, and what does this show about exogenous cues or salient distractors?
Theeuwes (2010) found that people in the ‘colour distractor’ condition were 20ms slower to report the orientation of the line in the diamond than participants in the ‘no distractor’ condition.
This shows that exogenous cues, or salient distractors draw our attention away from the top-down task and temporarily de-prioritise that task from the top of the bottle neck.
What are the explanations for blindness to gradual change? Give 2.
Our visual sensors operate on change basis which can be compared to an automatic light which detects motion changes. This is called ‘flicker’ or ‘motion’ detection. When a scene change is too gradual, these neurons are not stimulated. We have not evolved constantly compare current with previous stimuli, only to notice sudden changes which trigger neurons with different receptive fields.
How does a blank screen sandwich distract us from the following stimulus?
Since flicker/ motion detectors are not capacity limited, a blank screen sandwich activates many of them simultaneously. Then our capacity-limited attentional mechanisms are overloaded and we’re unable to focus on a change which might occur following the blank screen. The image which follows the blank screen also activates many of our motion/ flicker sensors causing the same overwhelm to our capacity limited attention.
Thinking about the change blindness date scene, what are some examples of high-level properties which attract people attention? Why are they called high-level?
When using eye-tracking technology, researchers found that participants’ attention was drawn to the peoples faces and bodies in the image, the food and wine. These are examples of high-level properties (“people are social animals”).
These items are called high-level because they use higher-level brain areas to process them.
How would broad motion change (eg the whole background is moving) have a similar effect on our attentional system as a global flash such as those used in blank screen sandwiches?
Broad motion change such as the whole background moving would have the same effect on our motion/ flicker detectors which are not capacity limited, stimulating a lot of them at once, as the flash used in a blank screen sandwich. Then our capacity limited attention would be unable to notice a potentially salient change occurring amongst the global movement.
What did Posner, Snyder and Davidson (1980) find when they directed participants attention to a location cue before presenting a stimulus there?
Participants performed better at processing stimuli which were placed at a location following the location cue, since their attention had already been directed there.
What are the 3 types of attentional selection?
3 types of attentional selection:
- Object selection & tracking selection
- Motion selection
- Feature selection (colour, shape etc)
If presented with a pattern including various shapes in various colours, what would happen if we tried to focus on all the red squares?
Frame the answer using feature selection.
We are unable to combine features using our feature selection mechanism, so we would end up attending all the red objects and all the squares.
During feature selection, what does parallel processing suggest?
When viewing a pattern with different coloured circles and attending all the circles of one colour such as blue, my brain must be processing all the blue circles in parallel.
Why is it hard to find a four-leaf clover and other complex shapes which are similar to their surrounding shapes?
Feature selection is not effective for complex shapes
Define ‘parallel search’ using the blue dot example
Parallel search involves processing all items in the search space in parallel (simultaneously). This is demonstrated by how quickly I can find the blue dot when it is surrounded by green and pink dots. I attend the whole area simultaneously and the blue dot jumps out.
During feature selection for a lone blue dot in a sea of pink and green dots, what are the 2 effects which make it fast and easy to locate the blue dot?
Both parallel processing and bottom-up attention (the blue dot jumps out at us) make it very fast and easy to locate.
When searching for a target that has 2 combined features, what is the effect of adding more distractors to the search space? How does this compare to feature selection for an item with only a single predominant feature?
The more distractors that are added to the search space, the longer it takes to identify an item with 2 combined features. However, when an item only has one predominant feature (find the blue circle when there are only circles in the space), distractors do not add time to the search; we use parallel processing for this type of search.
