Perception Flashcards
Perception
Organisation and interpretation of our sensory information by the brain in order to understand the world around us
Sensation
The information we receive through our senses
Binocular depth cues
Cues only detected when both eyes are used
Convergence
How hard the eye muscles need to work to view objects
Height in plane
Objects higher in the visual field appear further away
Linear perspective
When parallel lines converge to give distance
Monocular depth cues
Perceptual cues that can be detected with one eye
Occlusion
Objects obscured are further away
Relative size
Refers to the fact that smaller objects in the visual field appear further away
Retinal disparity
Left and right eye view slightly different images. The size of the difference give slightly different images
Visual constancies
Our ability to see an object as the same even if the actual image received by the idea has changed, for example if we get closer to it or move around it
Visual cues
Visual information from the environment about movement, distance and so on
Ambiguity
Images can be perceived in more than one way
Ambiguity
Images can be perceived in more than one way
Fiction
When a figure is perceived even though it is not part of the image (kanizsa triangle)
Misinterpretation of depth cues
Some visual illusion rely in misinterpreted depth cues in order for it to ‘work’. The brain seem linear perspective in the picture, creating the impression of distance and mistakenly applies the rule of size constancy
Size constancy
The brains ability to perceive familiar objects as the same size, despite changes in the size of the image on the retina
Visual illusions
The unconscious mistakes of perception
Direct theory
The argument that the rich information in the visual array is all the brain needs to perceive the world around it
Motion parallax
Types of monocular depth cue that provides the brain with important information to do with movement. Objects that are far away appear to move more slowly as we move than objects close to us
Nature
Refers to the aspects of behaviour that is inherited
Constructivist theory
We make sense of the world around us by building our perceptions based partly on the incoming data and partly using clues from what we know about the world
Inference
Taking info in front of you and drawing a conclusion about what it means based on what you already know
Nurture
Refers to aspects of behaviour that are acquired through experience
Sensation
Physical stimulation of the 5 senses by sense receptors
Perception
Brain interpreting and organising the sensory information
Difference between sensation and perception
Sensation is the detection of the stimulus, perception is the interpretation of what it all means
Visual cues
Info about movement
Constancies
Seeing object as the same from different angles and distances
Binocular depth cues
Retinal disparity - difference between the view of the left and right eye gives the brain info about depth and distance
Convergence - eyes point closer together when am object is close. Muscles work harder to know depth and distance Convergence
Monocular depth cues
Height in plane - objects higher up appear further away
Relative size - small objects appear further away
Occlusion - of an object obscured another, the one behind is further away
Linear perspective - parallel limestone appear closer as they become more distant
Ponzo illusion
Misinterpreted depth cue, perceive horizontal line higher up as longer
Muller lyer illusion
Misinterpreted depth cue, two vertical lines the same length. Line with outgoing fins appears longer
Rubin’s vase
Ambiguous figure, face and vase. Both pictures are correct. Brain alternates between both optiosn
Ames room
Misinterpreted depth cue, room shape of a trapezoid, people seem as different sizes even though they are the same
Size constancy
Objects perceived as constant size despite size on retina changing the distance
Misinterpreted depth cues
Objects apparently in the distance scaled up by the brain to look normal size, cause visual illusions. Eg. Ponzo
Ambiguous figure
Two possible interpretations of image brain can’t decide which one is correct
Eg. Necker cube, Rubin’s vase
Fiction
See something which is not there
Eg. Kamizsa triangle
Necker cube
Ambiguous image. One face appears on top, then a different one. Brain alternates between the two
Kanizsa triangle
Fiction. Contours crate am impression of a second triangle
Gibsons theory
The environment given us all the information we need
N - not learned, born with
4 things Gibson said
Sufficient info for direct perception
Optic flow patterns
Motion parallax
Influence of nature
Gibson - sufficient info for direct perception
Sensation and perception are the same thing
The eyes detect everything we need without having to make inferences
Gibson - optic flow patterns
When moving, things in the distance appear stationary, and everything else rushes past. Provides perceptual info about speed and distance Convergence
Gibson - motion parallax
A monocular depth cue
When we are moving past then, closer objects appear to move faster than objects further away
Provides perceptual information about speed and distance
Gibson - the influence of nature
Perception is inborn not learned
Evaluate Gibson theory
+ Real world meaning - based on WWII pilots so relevant to everyday life
- theory struggles to explain visual illusions - perception is seem as accurate but illusions tricks the brain, so theory is incomplete
+ support for the role of nature - Gibson and walk showed few infants crawl off a visual cliff, so are born with depth perception
Gregory theory
We use past experiences to make sense of the world
4 things Gregory said
Perception is a construction
Inference
Visual cues
Past experiences - role of nurture
Gregory - role of nurture
Perception is leaned from experiences
The more we interact, the more sophisticated our perception
Gregory - visual cues
Visual illusions occur because if incorrect conclusions from visual cues
Gregory - Inference
Brain fills in gaps to create a conclusion about what is being seen
Gregory - perception as a construction
Brain uses incoming info and info from what we already know to create a hypothesis / guess
Evaluate Gregory theory
+ support from different cultures research - people interpret visual cues differently ( hudsons study ) showing experience affects perception
- visual illusions - Gregory research used 2d visual illusions which are artificial, so theory may not apply to real world
Hudson study culture - results
Black and white schooled children more likely to perceive depth than unschooled
Hudson study culture - conclusion
Different cultures use depth cues differently, so have different perceptual sets
Hudson study culture - method
Black and white schooled and unschooled children showed a 2d drawing and asked whether the man elephant of antelope were nearer
McGinnies study emotion - method
Students showed neutral and taboo words which they had to say out loud, emotional arousal measured through gsr
McGinnies study emotion - results
Took longer to say taboo words and they caused the most emotional arousal
McGinnies study emotion - conclusion
Emotion affects perceptual set, in this case defenc e
Gilchrist and nesberg motivation - aim
To find out if food deprivation affects the perception of food
Motivation - method
Hungry (no food for 20 hours) and not hungry people were shown a slide of a meal, and they had to adjust the light to the level of the slide previously shown
Motivation - results
Food was perceived as brighter if they were more hungry
Motivation - conclusion
Sensitivity greater when we are food deprived. Hunger is a motivating factor
Motivation - evaluation
+ support from similar studies, expectation, strengthening the validity of the results
- ethical issues depriving people of food causes discomfort, a case of physical harm
- not like everyday life, pupils judged pictures rather than real food so it may not apply to the real world
Bruner and minturn expectation - aim
To find out if an ambiguous figure is seen differently when context is changed
Expectation - method
Pupils shown either sequence of letters or a sequence of numbers. They then saw the ambiguous figure and were asked whether the middle item was a b or 13
Expectation - results
Those who saw letters said b, visa versa for numbers
Expectation - conclusion
Shows expectation is affected by the context a figure is presented with
Expectation - evaluation
- artificial talk. Ambiguous figures are designed to trick people, decreasing validity
- independent groups, pupils variables may have caused the difference in results not expectation
+ real world application, the study can explain why sometimes serious mistakes are made in the world
