Simon and Chabris - Background & Theory Flashcards
What is visual perception?
a cognitive process in which an individual interprets, organises, and elaborates on information that enters the brain via the eyes
How does the brain perceive or interpret visual information?
via the optic nerve
Why is visual perception often criticised?
- too much information to process
- selective nature
How is the brain selective with information?
it filters out what is relevant and essential & omits what is not
What highly influences what people see?
the brain as it subjectively decides what to focus on
What is in-attentional blindness?
refers to not noticing something because attention is focused on something else
What does this study show?
that if someone is focused on a particular task (involving visual perception) other events (even unusual or unexpected) go unnoticed
What are the main types of theory for this study?
- Focused Visual Attention
- Change Blindness
- In-attentional Blindness
- Divided attention
What does the theory of focused visual attention say about our environment?
there is too much going on in every day life simultaneously than can be perceived at any one time
What are the mechanisms of attention meant to do?
select objects of interest for further processing
What does vision do as a mechanism of attention?
- provided by eye movements
- fixate on particular regions so they benefit from the greater activity of the fovea
What is the fovea?
region at the back of the eye responsible for central and sharp vision
What does vision allow?
us to fixate on things of importance in our environment
Why is attention necessary?
to detect environmental change
What does the change blindness theory suggest about people?
that individuals do not detect large and obvious changes in the environment when they are not in the scene of centre interest
What do people remember and perceive according to the change blindness theory?
only objects and details that receive focused attention
Why do people have in-attentional blindness even when fixated on something?
because a visually demanding task ‘loads’ the brains attention so an individual becomes blind to distractions and performance improves
What is a result of not paying attention to distractions?
improved performance
What is Kahneman’s theory about divided attention?
limited capacity theory
What is the limited capacity theory?
- limited amount of attention is allocated
- attention has a capacity
- capacity of attention is task dependent
What is Allport, Eysenck, and Baddley’s theory of divided attention?
multi-channel theory
What is the multi-channel theory?
- there are multiple modules for processing
- different modules for different tasks
- easy to divide between modules
What is Schneider and Shiffin’s theory of divided attention?
the automaticity model
What is the automaticity model?
- that automaticity develops with practice
- consistent mappings between stimuli and response
- action and reaction are consistent
- varied mappings = same action diff reaction
What is an example of the automaticity model?
tennis and badminton
- same action
- different reaction
tennis allows ball to hit the floor badminton does not
What is Norman and Shallice’s theory of divided attention?
SAS - Supervisory Attentional System
What is SAS?
- schemas
- activated or repressed
- influence of environmental conditions
- every stimulus condition turns on the activation of a response
- contention scheduling = control over behaviour and thoughts
- SAS controls schema activation
What do previous studies of attention show?
increasing interest in the issue of the precision of visual representations
What is the typical format of previous research?
- a continuous task
- requires to focus on one aspect of dynamic visual scenes whilst ignoring others
- an unexpected event
What are the results of previous research?
- majority of observers did not report seeing the unexpected event even though it was clearly visible
What issues did previous researchers encounter?
implications for the understanding of perception with and without attention
What approach which fell out of use did Sperry wish to revive?
empirical approach
Which researchers formed the basis of this study?
Becklen, Cervone, Stoffregen
What is Becklen and Stoffregen’s study about?
dual attention in dynamically structured naturalistic events
What are the key points of the dual attention - Becklen and Stoffregen study?
- videotapes of two naturalistic events
- basketball game and a vocalising face
Who are the key figures for previous research into in-attentional blindness?
Mack and Rock (1998)
What did Mack and Rock do?
ask participants to judge which of the two arms of a cross were longer
What are the key points of Mack and Rock’s study?
- 4th trial - unexpected object appeared
- told on some trials that something would appear (demand characteristics)
- 25% in-attentionally blind when cross was presented at fixation and object parafoveally
- 75% in-attentionally blind when cross parafoveally and unexpected object fixation
- observers typically notice an unexpected object if it is their own name or a smiley face
What is object parafoveally?
when the object is not fully in sight and blurred into the background
What did Rubin and Hua find?
that observers do not tend to notice their own name if a letter is changed
What was Becklen and Neisser’s previous research into selective looking?
- two overlapping simultaneous events
- hand slapping game
- people passing a basketball
What did Becklen and Neisser’s procedure look like?
had to press a button every time they saw a slap or a pass
What was Becklen, Neisser, and Littman’s previous research into selective looking?
- two ball games
- black shirts vs. white shirts
- a transparent woman with an umbrella = unexpected event
What was Becklen and Cervone’s previous research into selective looking?
- investigating the effect of eliminating the delay between umbrella woman’s appearance and the questioning of subjects
- found no difference
What was Stoffregen’s previous research into selective looking?
- a single video camera
- no superimposing where the umbrella woman occlued (obstructed) the players
- only had 12 passes
- umbrella woman was noticeable for longer (12 seconds)
- people smaller on screen
- 3/20 reported seeing unexpected object
