Lecture 5 Flashcards
What is TMI?
Too much information
What is selective processing?
reducing the load of visual processing by filtering information
What is retinal filtering?
a type of selective processing - colour information only encoded in the central visual field
What is cortical filtering?
fine details are only represented in central vision
What are the two types of eye movements?
- saccades
2. fixations
What are saccades?
small, rapid eye movements
What are fixations?
pauses in eye movements that indicate where a person is looking
What are two things that determine where we look at?
saliency - areas of stimuli that attract attention
What are two reasons eye-movements can be voluntary?
- scene schema - prior knowledge about what is found in a certain place e.g. microwave
- task demands override stimulus saliency e.g. what am i doing next
What are the three types of shifting attention?
- Exogenous attention
- Endogenous attention
- Dynamic attention
What is exogenous attention?
bottom-up processing, rapid shift geared towards survival
What is endogenous attention?
top-down processing, slow shifts that are goal directed
What is dynamic attention?
top-down processing, smooth shifts of attention over time
Can attention be directed to without eye movement?
yes
What is divided attention?
paying attention to more than one thing at a time
What is attentional resolution?
you can see the dots in the outer ring but you can’t count them
What are four things attention does?
- attended objects are processed more efficiently e.g. Posner
- better acuity and recognition performance
- attention binds the world together
- attention helps us find things
What is the binding problem?
features of objects are processed separately in different areas of the brain
How does binding occur? What is the theory?
Feature Integration Theory - attention binds features together
What can failures of attention lead to?
illusory conjunctions - I might think that green apple is a red apple because the pre-attentative features are ‘free-floating’
Who tested illusory conjunctions?
Triesman & Scmidt
What did the test on illusory conjunctions find?
Coloured shapes & numbers: incorrect associations of features occurred 18% of the time, asking Ss to focus on targets eliminated this
What is Balint’s syndrome?
can only attend to one thing at a time - parietal lobe damage
What is spatial visual attention?
how do we allocate attention or find things in a complex arrays or scenes?
What is the visual search paradigm? What does it compose?
subjects search for a target among distractors - set size (e.g. how many people on the beach) - subjects judge whether subject is absent or present - judge reaction time
What were two findings of Treisman’s experiment on conjunction searches?
conjunction searches - when you search for a object amongst a set that has properties that are similar e.g. size, colour, shape
found that RT increased with set size for conjunction targets
argued that conjunction searches are serial and self-terminating
What are three basic features that ‘pop-out’ in displays?
- colour
- orientation
- size
What can we attend to?
- spatial items - spotlight metaphor
- a particular feature - e.g. blue
- objects - attention can select an entire object
What did the evidence for object-based attention that Egly et al. find? 2 points
- fastest reaction time at targeted position
2. “enhancement effect” for non-target within the target rectangle
What was Colby’s experiment about attention and the brain about? (monkey)
Monkey trained to keep eyes fixated on a dot whilst peripheral light was flashed on the right
What did Colby’s experiment about attention and the brain find? (monkey)
Neuron responded well when monkey was attending to peripheral light, neuron responded poorly when monkey was not attending to it
What is the hypothesis that is linked to attention and binding in the brain?
Synchrony hypothesis - neurons firing to same object synchronise with each other e.g. orchestra metaphor
Can perception occur without attention, why?
scenes can be processed in the absence of attention - observers could see an animal in the picture 76% of the time
What did the study on autism and attention find?
autistic people look at socially irrelevant stimuli - thus when autistic people are in a social situation they may perceive the world differently
