sensation and perception Flashcards
what are sensations?
raw info taken in by sense, affects behaviour and mental processes
what is the process of sensation?
- accessory structure modifies energy
- receptor tranduces energy
- sensory nerves bring encoded info to CNS
- initial processing in thalamus
- processing in cerebral cortex
what does sensation in the cerebral cortex produce?
perception
what sensation is not initially processed in the thalamus
smell
what are the types of codes?
temporal and spatial
what is a temporal code?
timing of impulse
what is a spatial code?
location of firing neurones
what is psychophysics?
relationship of the physical energy in the enviro and the psychological experience
what is the absolute threshold
the minimum amount of energy that can be detected 50% of the time
what is sensitivity in relation to signal detection?
intensity of signal, capacity of sensory systems and is affected by noise level
what is response criterion in relation to signal detection?
willingness to respond to a stimulus
what are some characteristics of waveforms?
- amplitude
- wavelength
- frequency
what is the amp of a waveform?
height from baseline to peak
what is the wavelength of a waveform?
distance from peak to peak
what is the frequency of a waveform?
cycles/second (Hz)
what are the psychological dimensions of sound (experience)?
- loudness
- pitch
- timbre
what is loudness in relation to dimensions of sound?
amp, measured in dB
what is pitch in relation to dimensions of sound?
frequency, higher or lower tone
what is timbre in relation to dimensions of sound?
wave patterns added to lowest frequency, depends on specialised neurons
what are the main structures of the ear?
- outer ear
- middle ear
- inner ear
what structures are part of the outer ear?
- pinna, collects and shapes sound
- ear canal
what structures are part of the middle ear?
- tympanic membrane
- ossicles: malleus (hammer), incus (anvil), stapes (stirrup)
what structures are part of the inner ear?
- cochlea
- basilar membrane
- organ of corti
- hair cells
- acoustic nerve
what are the types of deafness?
- conductive deafness
- nerve deafness
what does conductive deafness prevent?
prevents accurate conduction of vibrations due to fusion of ossicles
what does nerve deafness result from?
damages to acoustic nerve, hair cells
what are the two ways frequency can be coded?
- place theory
- frequency matching (volley) theory
what part of the electromagnetic spectrum is visible light?
400 to 750 nm
what are the cells found in the retina?
- photoreceptors
- ganglion cells
- interneurons
what is hue?
colour
what is colour saturation?
purity
what is brightness in relation to colour?
intensity
what is visual transduction?
converts light energy into neural activity
what is the trichromatic theory of colour vision?
you can produce any colour by mixing pure lights of blue (440nm), green (510nm) and red (700nm)
what are the three types of cones?
- short wavelength
- medium wavelength
- long wavelength
what colour are short wavelengths most sensitive to?
blue
what colour are medium wavelengths most sensitive to?
green
what colour are long wavelengths most sensitive to?
reddish-yellow
does trichromatic theory of colour vision explain afterimages?
no
does the Opponent-Process theory of colour vision explain afterimages?
yes
what is an afterimage?
an image that continues to appear in the eyes after a period of exposure to the original image
why does an afterimage appear?
because photochemical activity in the retina continues even when the eyes are no longer experiencing the original stimulus
what are colour-sensitive visual elements grouped into pairs of?
red/green, blue/yellow, black/white
what is the kinaesthetic sense?
tells the brain where parts of the body are
what is the intensity of the stimulus encoded by?
- firing rate of individual neurons
- number of neurons stimulated
what happens according to the gate control theory?
pain is a function of the balance between info travelling into spinal cord through large and small nerve fibres, the gate is closed and there is no pain
what are the two types of nerve fibres that carry pain signals from skin to spinal cord?
- A-delta fibers
- C fibres
what are the three approaches to perception?
- computational model
- constructivist approach
- ecological approach
what is the computational model of perception?
what steps a computer takes to solve perceptual problems
what is the constructivist approach to perception?
we create representations from bits of info and our experiences
what is the ecological approach to perception?
how info helps us adapt to and use the enviro
what are gestalt principles of grouping of perceptual organisation?
- proximity
- similarity
- continuity
- closure
- texture
- simplicity
- common fate
what are Palmer’s additional grouping principles of perceptual organisation?
- common reign
- connectedness
- synchrony
what is stroboscopic illusion based on principles of?
likelihood and simplicity
what is size constancy?
changes in size of a retinal image interpreted as changes in distance, not change in actual size
what is shape constancy?
the perceived shape of an object remains the same even when seen at different angles
when does shape constancy break down?
at extreme angles
what is bottom-up processing?
basic feature analysis
what is top-down processing?
- schemas and perceptual sets
- impact of context
- impact of motivation
what is a schema?
a cognitive structure that serves as the framework of one’s knowledge about people, places, objects and events
what is a pareidolia?
a psychological phenomenon that causes people to see patterns in a random stimulus
what is pareidolia driven by?
top-down processing
what is the object superiority effect?
patterns are more likely to be detected in three-dimensional objects, rather than random patterns of lines
what is the word superiority effect?
words are easier to detect than non-words in strings of random letters
what is overt orienting?
looking directly at someone when talking to them
what is covert orienting?
listening to another conversation while seeming to listen to something else
is voluntary attention control a top-down or bottom-up process?
top-down processing
is involuntary attention control a top-down or bottom-up process?
bottom-up processing
what does parallel-processing describe?
ability to search for targets rapidly and automatically
