Perception Flashcards
What is the path of sensations and perceptions?
- stimulus energy (light, sound, smell…)
- sensory receptors (eyes, ears, nose…)
- neural impulses
- brain (visual, auditory, olfactory areas)
What are exteroceptive sensations?
- any form of sensation that results from stimuli located outside the body detected by sensory organs
What is the stimulus type for vision/sight?
Light entering eye
What is the stimulus type for audition/hearing?
Vibrations in the air entering eat canal
What is the stimulus type for touch?
Pressure, heat and vibrations on skin
What is the stimulus type for gustation/taste?
Chemical compounds in the mouth
What is the stimulus type for olfactory/smell?
Airborne chemical in nasal passage
What are interoceptive sensations?
- sensations from inside our body
- proprioception
- nociception
- equilibroception
What is proprioception?
sense of where our limbs are in space
What is nociception?
sense of pain due to body damage
What is quilibrioception?
sense of balance
What do dancers have?
increased interoceptive accuracy
- understanding of what’s happening in the body
- dancers can estimate heart rate more accurately than non dancers
the study that showed dancers have increased interoceptive accuracy, the authors report dancers could estimate heart rate more accurately than non-dancers, which was unrelated to fitness levels or counting ability.
In this study, ______________ is a nuisance variable that was controlled for in their experiment.
fitness levels and counting ability
What is synesthesia?
- neurological condition in which one sense automatically triggers the experience of another sense
- hear colours
- smell sounds
- see time
- genetic component
- more common in women
- specific pairings tend to be stable over the lifetime of the individual
What is grapheme-colour synesthesia?
- colour with letter/numbers
- 7 is pale blue with a pleasant, soft, nice personality
What is chromesthesia?
- sound can evoke an experience of colour
What are forms of synesthesia?
- grapheme colour
- chormesthesia
Who is more like to have synesthesia?
- artists
- artists are 8 times more likely to have synesthesia than non artists
Why is synesthesia important?
- represents the importance of individual differences
- encourages a view that brains are organized as “talking” circuits
- it is explained as cross-talk between processing regions for different senses
What is the McGurk effect?
- the input from one sense (vision) influencing the perception of the input from another sense (sound)
- hear baa, then faa because lip movement changed but he was saying baa both times
- when you hear what you see
- a multisensory illusion
- illustrates integration of and cross-talk amongst senses
- illustrates the dominance of visual input
What is apart of the visual system?
- early visual processing
- late visual processing
What is early visual processing?
- sensation
- eyes and the optic nerve
What is late visual processing?
- perception
- the visual cortex or occipital lobe
What are the steps to early visual processing?
- Light waves enter the eye
- projected onto the retina
- the retina forms an inverted image - Retina photoreceptors convert light into electrical activity
- rods: low light levels for night vision
- cones: high light levels for detailed colour vision - The electrical signal is sent to bipolar cells
- sent on to the ganglion cells - The signal exits through the optic nerve
- to theh brain for later visual processing
What is information processing?
- millions of photoreceptors in each retina converge onto 100 times fever ganglion cells —> optic nerve –> brain
- input from the eyes to the brain is compressed
How are the photoreceptors distributed?
- cones are concentrated in the fovea (small area on the central part of the visual field)
- center of visual field is most detailed
- rods are mostly in the periphery
- periphery of visual field is less detailed and less accurate
What is perceptual filling in?
- fill in periphery
- why we don’t see our blindspot
What is the blindspot?
- photoreceptors are at the back of the retina
- ganglion cells are at the front
- ganglion cells make up the optic nerve that exits to the brain
- must pass the photoreceptor layer
- at this exit location there are no photoreceptors, so no vision
What is early to late visual processing?
- thalamus (lateral geniculate nucleus, LGN) is the way station
- the optic nerve of each eye transmits information to both hemispheres
- contralateral representation (left visual field is perceived via the right hemisphere and vice versa)
What are the steps to late visual processing?
- primary visual cortex
- specialized regions that process specific visual attributes or features (edges, angles, colour, light, simple movement)
- visual association areas interpret visual signal, assings meaning
What is the ventral pathway?
- what pathway
- occipital to temporal lobes
- shape, size, visual details
What is the dorsal pathway?
- where pathway
- occipital to parietal lobes
- location, space, movement information
What happens when there is damage to the dorsal where pathway?
- dorsal damage with intact ventral stream
- accurate performance on object recognition or matching tasks
- impaired performance on visual guided action (picking up an object appropriately)
- dorsal could represent action
- harder to process spatial information, depth perception, estimating movement and direction of objects
- akinetopsia
- optic ataxia
What happens when there is damage to the ventral what pathway?
- ventral damage with intact dorsal stream
- impaired performance on visual object recognition or matching tasks
- can pick up objects
- ventral could represent perception
- difficulties recognizing everyday objects (often from damage to the lateral occipital cortex)
- difficulties can be selective to visual categories (faces)
- functional specialization within the ventral pathway
- prosopagnosia
- agnosia
What is bottom-up processing?
- the influence of information from the external environment on perception
- information from the sensory organs (eyes) to the visual cortex
What is top-down processing?
- the influence of knowledge (expectations, context, and goals) on perception
- information from higher processing brain regions (prefrontal cortex or higher visual processing areas) is sent back to the sensory organs
What is the constructivist theory of perception?
- we use what we already know and expectations to predict how to perceive sensory information
- visual information is ambiguous, and perception requires top-down processes
- relies on the influence of top-down processes to vision
- illustrates how perception is an “illusion”
- perception is knowledge and expectations
- knowledge about assumptions about how the world works and affects perception
- our context activates expectations affects perception
- demonstrated by illusions
What is the Ponzo illusion?
- the line at the back looks longer because of our expectation of size and depth perception
What is terror subterra?
- the monster at the back looks bigger than the one at the front
- distance cues in the image make monster seem farther away
What is the world is lit from above?
- we assume light source originates above us, resulting in predictable patterns of shadows which we use to predict depthW
What are ambiguous bistable figures?
- face/rat
- girl/old lady
- sax plater/women’s face
- skull/women putting on makeup
- context affects what we see
What is the rotating snake illusion?
- circles appear to rotate, perceive motion
What is the letters in context effect?
- the ability to read words in sentences even when the letters in the middle of some the words are mixed up
- you expect to see real words in a sentence
What is the colour in context effect?
- the context of a colour appears to change how you see that colour
- colour perception depends on he wavelengths of light that fall on the retina and our expectation from experience of how objects look under contexts of illumination
What is the Munker-White illusion?
- same shade of grey but one column is behind the black, the other is in front
- when black lines are on top we see darker grey
What are gestalt organizational principles?
- gestalt psychology: there are fundamental organizational principles to deal with ambiguity in our environment
- these principles are based on knowledge and experience (top-down processes) and shared among people
- The principle of experience
- Visual grouping principles
What is the principle of experience?
- figure ground segmentation
What is figure ground segmentation?
- image segmentation depends on sensory input, detect edges or shadows (bottom-up)
- experience and knowledge also drives figure-ground segmentation
- regions perceives as the figure are the ones that are more familiar and more easily named to the observer (top-down)
The Cog Dog loves watching rabbits hop past her window – she spends much of her day doing this, especially when Dr. Sheldon is teaching Cognition. If you showed her this image, what is she likely to see?
a. a duck because it is familiar to her
b. a rabbit because it is familiar to her
c. both a duck and a rabbit
d. neither a duck or rabbit due to interference
b
What are the visual grouping principles?
- principle of proximity
- principle of closed forms
- principle of good contour
- principle of similarity
What is the principle of proximity?
- objects or features that are close to one another in a scene will be judged as belonging together
What is the principle of closed forms?
- we see a shape in terms of closed forms, and we like to see items that enclose as whole
What is the principle of good contour?
- we perceive objects as continuous in cases where it is expected that they continue
What is the principle of similarity?
- we organize objects or features of a scene based on similarityW
What are direct models of perception?
- against the idea that top-down processes are needed for perception
- a passive bottom-up approach to perception
- sensory information is rich enough for perception
- requires an ecological approach to understand perception, study it in the real world
- the ambient optical array (AOA) that reaches the retina has enough information to direct perception and movement
- these are cues (computational tricks) in the AOA (not in the mind) that are used to guide perception and action
- bottom-up cues
What are the cues in the AOA?
- topographical breakages
- scatter reflection
- texture gradient
- affordances
What are topographical breakages?
- discontinuity helps see edges and define objects
What is a scatter reflection?
- how widely light scatters off an object’s surface provides cues about the nature of the surface
- smooth surface: light less scattered
- rough surface: light more widely scattered
What are texture gradients?
- near objects are farther apart and far objects are closer together
- incremental changes in texture can provide information about your movement and distance
What are affordances?
- cues indicate potential function of an object
- visual cues in our environment
- perceived directly and immediately
- provides information on the potential function of an object
- we see based on what we can/need to do in the environment
Which of the following statements is true about the indicated modes of perception?
a. Direct models suggest our experiences can affect perception
b. Constructivist models suggest there are computational tricks in our visual stream that direct perception
c. Constructivist models are passive top-down models
d. Direct models are passive bottom-up models
d