Cognition - Attention and Perception Flashcards
What is the definition of perception? (Sekuler and Blake 2002)
The acquisition and processing of sensory information in order to see, hear, taste or feel objects in the world; also guides an organisms actions with respect to objects
What is the structure of the eye?
SEE FUNDAMENTS OF NEUROSCIENCE
Photoreceptors/bipolar cells/retinal ganglion neurons/blindspot
What is the structure of the primary visual cortex and other cerebral visual processing areas?
SEE FUNDAMENTS OF NEUROSCIENCE
Retinogeniculostriate pathway/retinotopic projections/parvo+magnocellular pathways
Dorsal/ventral streams - action vs perception
What is the Muller-Lyer illusion and what does it suggest about vision?
Two lines same length with different arrow heads on the ends - making them appear shorter/longer
There is a difference between vision-for-perception and vision-for-action
For action = accurate interpretation of distance etc is necessary for daily functioning (ie dorsal stream)
For perception = highlighted by the ML illusion; though when pointing at the ML illusion (ie introducing an action component to the processing), the effect is diminished
What are the qualities to a colour?
Hue = the colour itself Brightness = intensity of light Saturation = pale/vivid
Why do you get negative afterimages if staring at a colour inverted and hypersaturated image?
Complementary colours = opponent processes - red/green, yellow/blue, black/white
You experience decreasing sensitivity to the dominant stimulus colour
What is colour constancy?
Colour perception is relatively independent of light conditions/brightness
What determines colour constancy?
Contrast - local = surfaces that share edges with the target; global = across the visual scene - both serve as cues to colour and in their absence, colour constancy drops
Experience - we expect certain objects to have certain colours, OVER ADJUSTING IN EXPERIMENTS ??
Chromatic adaptation - we adapt to light conditions and so sensitivity decreases over time
How do monocular cues contribute to depth perception?
Perspective - linear ie illusions of depth in 2D (vanishing points); aerial ie blurring in the distance
Size - familiar ie knowledge based (I know how big a standard pint is); relative ie the same objects vary in size depending on how far away you are as an observer (“okay one last time - the ones in here are small, the ones out there are far away”)
Interposition - occlusion ie closer object is on top (can even be seen in imaginary 3D space in a 2D image)
Shadows - dimmer objects seem to be father away
Movement cues - motion parallax ie objects in the foreground go away from the direction of travel and objects in the background go with the direction of travel
How do binocular cues contribute to depth perception?
Stereopsis - small differences in image from each eye (binocular disparity) are combined into a single image
How do oculomotor cues contribute to depth perception?
(con/di) Vergence - eyes move towards each other when viewing close objects - get muscle feedback
Accommodation - changes in focal length ie thicker/thinner lens
What is the aim of combining perceptual cues?
Minimising ambiguity + maximising similarity = clearer perceptions of the way things are
What is the function of attention?
Mediation - between internal and external environments
Selectivity - deciding on what information should be processed and what should be discarded - because we do not possess the capacity to process everything fully, nor do we need to
What are selective/divided attention?
Focused/selective - concentration on a single stimulus and ignoring others and distractions
Divided - attending to more than one stimulus/type of stimulus ie multitasking
What is active/passive attention?
Active - self directed, top down
Passive -
environment directed ie unexpected noise, bottom up
What is internal/external attention?
Internal - directed towards internally generated info
External - directed towards the environment
What is orienting of attention?
Moving the focus - covert = without moving eyes/head; overt = with moving eyes/head
What is the Posner cuing task?
Aim to detect the target - reaction times are measured
Participants presented with two boxes then a valid or invalid cue which indicates which box the stimulus is to appear in (or if invalid, the other box)
Cues can be endogenous = at the centre of the screen, above a fixation point, relying on info from the central visual field; or exogenous = relies on info outside the central visual field ie highlighting the box
Stimulus onset asynchrony - time between cue and appearance of stimulus; has an effect on attention, and also interacts with endo/exo cue type
What has the Posner cuing task found?
Attentional shift (covert) to target area occurs prior to eye movement (overt)
Spatial attention is not completely reliant on conscious visual input
Process behind orienting = disengagement of current focus, movement to selected target and engagement of selected target
Parietal lobe damage, parkinsons, ADHD and age impact performance
What types of information search are testable with visual search paradigms?
Feature search - looking for a specific feature ie finding the red T in a group of blue Ts
Conjunction search - looking for a set of features ie finding a black L in a group of black Ts
What is an attentional blink?
Inability to respond to a second target when presented very soon after the first
(Heim, Benasich and Keil, 2013)
NEEDS CLARIFICATION
What is object based attention?
Measure using two overlaid, semi transparent images of a man and a house - said that you cannot see both at a time and that you selectively attend to one image then the other
Different neural activities despite same spatial location
What are the limits to attention?
Capacity - how many things can be attended to at a time
Bottleneck - for what (types, numbers) can be processed
Problem of early selection or late correction:
Early - limits at the start of attending, due to perceptual abilities; late - limits at the end of attending ie all info processed up to level of meaning then filtered if necessary
What is Broadbent’s filter theory?
Information progresses from sensory register through a selective filter where irrelevant info stops being processed and only the relevant content passes into STM
What is Treisman’s attenuation theory?
Information progresses from sensory register through an attenuator which (???) upregulates or downregulates the saliency of the stimuli before transfer to STM so the STM receives some information more preferentially (???)
What is Deutsch and Deutsch’s theory?
All information passes through the sensory register to STM but the output of STM is what becomes salient during processing in STM ???
What is inattentional blindness?
Failure to register changes in objects that are not your immediate focus of attention
Example - gorilla and basket ball study
Depends on whether the object will attract attention ie is it similar to the focal stimuli (colour, shape, category)
What is change blindness?
Difficult to spot changes in your environment as they are occuring
Example - confederate asks for directions, gets swapped out for someone carrying a door
More complex than inattentional blindness
Difficult to actively find changing features even when actively trying
Easier to detect when object type changes as opposed to object incidence
Requirements: paying attention to the change location, encoding the old stimulus, encoding the new stimulus, comparing them both, consciously recognising there is a change - depends on working memory capacity
What are the features of divided attention?
Potentially analogous to dual tasks in WM
Multiple resources or central resources?
Serial processing w/switching attention or parallel processing both tasks at the same time?
