Perception Flashcards
What is the absolute threshold
Smallest amount of stimuli we can detect.
What is subliminal stimuli
Any stimuli that is below the absolute the absolute stimuli and we can’t process
What is the the difference threshold
aka
Minimum amount of stimulus that is required to feel a change from the original stimulus
aka Just Noticeable Difference (JND)
What is Weber’s law
Change is proportional to the original intensity of a stimulus
(greater magnitude of stimulus, larger diff must be added to be noticed)
and
Different senses have constants for the JND that are all different.
(eg: vision has 8% (doesn’t actually is for eg) and so the new stimuli has to be at least 8% brighter/darker to be noticed or same for sound 5% - has to be 5% louder or softer to tell a diff)
What is the signal detection theory
what are those factors together called.
investigates the effects of the distractions and interference we experience while perceiving the world
how motivated we are to detect certain stimuli and
what we expect to perceive
Factors together ^ called –> Receiver operating characteristics.
Signal detection theory -
False positive
False negative
hit
miss
False positive - think we perceive a stimulus which isn’t there
False negative - don;t perceive a stimulus which is presnt
Hit - perceive a signal which is present
Correct rejection - don’t perceive a stimulus which isn’t there.
What is top down processing
when is it used
how does it work
what is backmasking
When you use your background knowledge to fill in gaps in what you perceive.
Look at the whole image/object to make sense of the parts
Used when you are familiar with something and apply the schemata/schema.
We form schema which are mental representations/sets of how we expect the world to be
What is backmasking
essentially manifesting what you want to see
eg: Expect to see an image in the clouds so that’s why you actually see an image in the clouds.
What is bottom up processing.
Used when you look at something you’re unfamiliar with for the first time.
Look at features first and then conduct feature analysis. Make sense of the overall object after processing features.
3 Main types of attention
Selective
Divided
Focus
What is selective attention
2 theories
Chose to process certain information
Theories:
Filter - Donald Broadbent - imagine a bottle neck that only allows certain things that fit through the bottle neck to pass through. Stimuli pass through a form of screen/filter.
Filter attenuation - Triesman - States that stimuli that doesn’t pass the filter (in the broadbent theory) aren’t completely blocked and can exist in the unconscious, etc.
What is divide attnetion
What kind of tasks can you use divided attention for
How does it decline
trying to focus on more than one task at a time
Can only use divided attention in automatic tasks not controlled tasks that require full attention
Decline with age
What is focused/sustained attnetion
Try to ignore certain stimuli and continue to focus on only the stimuli you want to.
What is figure ground relationship
How the image you take as the background changes the image you see
look at barrons page 131 to understand. If white is tasking as backgrnd - 2 faces. if black is taken as backgrnd - a glass.
What are the gestalt rules
Proximity - objects that are close together are perceived as one object.
Similarity - objects that are similar are perceived in one group.
Continuity - images form a continuous pattern are more likely to be perceived as belonging in the same
group.
Closure - Objects that make a recognizable object are perceived as one group.
What are the constancy
what are the rules
Ability to maintain a constant perception of an object even though it keeps changing (variations in lighting, changing angle of vision)
Size - account for distance to accurately produce a constant size of an obj
Shape - constant shape of an obj no matter the viewing angle
Brightness - constant colour of an obj even with variations in the amt of light the obj reflects.
What is the stroboscopic effect
Image in series of still pictures presented at a certain speed will appear to be moving
What is the phi phenonmen
A series of lightbulbs turned on and off at a particular rate will appear to be one moving light
What is the autokinetic effect
If a spot of light is projected steadily onto the same place on a wall of an otherwise dark room and people are asked to stare at it, they will report seeing it move.
2 types of depth perception
what are they
by what age
what exp to prove (for one of them)
Monocular cues - don’t require both eyes to perceive
Binocular cues - need both eyes to perceive the depth. Develops around 3 years old - Gibson visual cliff exp.
What are the monocular cues
Texture gradient - patterns of distribution of objects, grow more dense as distance decreases
Vanishing point - 2 lines become undisguisable into a single line then disappear.
Interposition - An object nearby partially blocks the object behind it
Linear perspective - Vanishing point
Relative size cue - the closer things are to us the bigger they are vice versa
Shadowing - Add a light source to imply depthness
aerial perspective - blue light which scatters in the atmosphere.
What are the binocular cues
Retinal disparity - Retinas are 6 cm apart and produce 2 different images. The closer an object is to us the more disparity there is between the images.
Convergence - As an object gets closer, the eyes move towards together to maintain focus. The muscles convey to the brain how close the eyes are to tell how close the obj is.
Accommodation - the further away an object is the more the muscles relax. The closer it is, the more the muscles contract. The lens of the eyes thicken.
What is stereopsis
3D image of the world resulting from binocular vision.
What are illusions
the 2 types
Illusions - misinterpreting a stimulus
Horizontal-vertical illusion - Always perceive vertical lines longer than horizontal lines even if they are the same length.
Muller Lyer illusion - Always perceive the outwards facing/open lines to be longer even if they are the same length.
What is the effect of culture on perception
African people - horizontal-vertical illusion - Often subjected to verticality (tall trees etc)
Western culture - more Muller lyer illusion - Always live in right angled structures (apartments, etc) and thats why they underestimate closure.
What is extra sensory perception
Claim to have a sensation outside the 5 senses
6th sense
What is the law of Pragnanz
Always perceive a good/proper figure and see objects in the simplest forms.
