Change blindness
Failure to detect an obvious change in a visual scene even with full attention devoted to detection
Rensink´s experiment (change blindness)
The participants in the study get to look at two alternating pictures and are supposed to press a button when they see the difference between the two pictures. This was done both with a change in marginal interest and a change in central interest.
RESULTS:
- Despite being asked to detect changes participants do not do so immediately
It takes longer to notice changes in scene features of marginal interest (irrespective of type of change)
Change in marginal interest
something not that important to the picture, harder to notice
Change in central interest
something that’s central to the image
Inattentional blindness (Simons & chabris)
The failure to notice clearly visible target due to attention being diverted from the target.
Attentional blink
- failing to notice a particular information in a stream of information
- We fail to notice information in face of simultaneously present competing information (change blindness, inattentional blindness)
- We fail to notice a stimulus in a stream of information (attentional blink)
Attention: a selective process by which attended information is processed more efficiently than non-attended information
The cocktail party problem
- E.C. Cherry´s “shadowing” experiments:
the participants had headphones with two different conversations playing at the same time. They were then told to repeat what had been said in one of them. In the other one they would hear their own name, if they noticed their name they would have more errors in repeating what had been said in the initial task they were attending to.
Conclusion: unattended information gets processed
Donald Broadbent´s filter theory
- Only information that is filtered during attention is processed further
- Only attended information will be processed to a higher level so that we can make sense of it.
- Early selection: information is filtered early in the information processing stream; other information is completely disregarded
- The filter theory got criticized because of the cocktail party effect which is that you can hear your name being called in a cocktail party although you´re not attending to it.
- If the filter theory is right you shouldn´t have been able to hear your name to begin with, because it was filtered out in the begining.
Lavie´s load theory
- if the primary conversation is interesting or difficult you won´t hear your name being said in the background, if the conversations is boring or uninteresting you´ll be distracted
- When a central task gets a higher load, outside information doesn´t get to a certain processing and can´t distract/interfere
- High load: harder task, more complex
Low load: easy task
Kahneman´s resource theory
- Attention = is a “mental effort”
- Mental effort is a finite resource (available capacity) and is centrally controlled, you can control what you attend to
- Attention-related mental effort depends on the task demand (e.g., “load” of the task)
- Several activities can be attended at the same time (distributed gradually), provided that total demand does not exceed the available capacity
- The demands or load of the attended task determine how much of this capacity is spent
Dual task experiment
- Participants were asked to either count hand movements, ball passings or both at the same time.
- Dual-task situation: attend to both at the same time
The errors skyrocket when you have to attend both at the same time
Dual task experiment (real life example)
accidents in traffic happen when you do several things at once
Endogenous control of attention
Attention is influenced by an individual’s expectations.
Attention is directed in accordance with internal goals (“top down”)
Example: Where is Wally
Exogenous control of attention
Attention is attracted by stimuli (lights, loud noises etc.).
Attention is attracted by a stimulus (“bottom up”) reflexive
Stop sign
If a person only had endogenous control of attention they would only be looking for/attending to what they expect to see, where they expect to see it. (Shnoda et al. 2001: Stop sign was more likely to be detected by drivers if it was in the position where it´s expected to see.)
Can inattentional blindness be explained by the recourse theories?
In the Simons & Chabris expirement there was either a gorilla or a woman with an umberella passing by either a white or a black team that was playing basketball. The participants watching the movie got either a easy task which was counting the total number of passes made by the team or a hard task which was keeping a seperate count of the aerial and bounce passes. With the harder task the results were worse. That supports the Kahneman´s resource theory wherein we attention is a limited recourse that depends on the load of the task.
Functional cerebral distance
A neuropsychological principle that states that “separate control centers that are functionally close together will conflict if they are independently engaged in unrelated activity”, e.g. If you have to visual stimuli they will easier conflict that if you have one visual and one audio.
One attention resource or multiple resources?
-If two functions are controlled by the same brain hemisphere they will interfere with each other e.g.
Balancing a wooden rod on the right hand is more interfered with by talking than balancing it on the left hand (Kinsbourne and Cook, 1971). This is because talking ad controlling the right hand are both controlled by the left hemispheres.
Object -based vs. spatial attention
- Slower reaction time to target in uncued compared to cued objects (although target at same location, on average across trials)
Object matters for your attention, not just space
Pop-out effect
The bright color of a flower might attract our attention.
Feature integration theory, Anne Treisman (1980)
- Preattentive processes lead to an automatic processing based on colour, motion and orientation etc. (because we have special spaces in the brain that do that)
- Focused attention is used when we need to combine features to bind them together.
The binding problem: the use of attention to bind different features together
Exogenous attention for phobic stimuli
- Instruction: move eyes to the only gray cicle and indicate the letters orientation
- Distractors: spider, mushroom, flowers
- The task is harder when there’s a spider distractor for people who have arachnophobia
Two fronto-parietal attention control networks
Ventral, stimulus-driven (button up, exogenous) attention control system
Dorsal: goal directed (top- down, endogenous attention control system)
