Sensation and Perception Flashcards
What is sensation?
The process through which the senses detect visual, auditory, and other sensory stimuli and transmit them to the brain
What is perception?
The process by which sensory information is actively organized and interpreted by the brain
What does sensation do?
Gives you the visual cues
What does perception do?
Fills in the blanks
What is absolute threshold?
The difference between not being able to perceive a stimulus and being able to just barely perceive it. (nothing versus something)
What is the difference threshold?
The smallest increase or decrease in a stimulus that’s required to notice a difference; called the ‘just noticeable difference’ (JND). (something vs. more/less of something)
What is sensory adaptation?
Becoming less sensitive to unchanging sensory stimulus over time,
automatic process,
allows us to shift attention
What are 2 kinds of processing functions?
Bottom up processing, top down processing
What is bottom up processing?
Individual components of stimulus detected by sensory receptors, bits of information translate mites to areas of brain to be combined and assembled into unified whole
What is top down processing?
Past experience and knowledge influence our perceptions,
we find meaningful links between the individual elements taken in by our sensory receptors
use existing knowledge, concepts, ideas, expectations
What is perceptual set?
Where individuals’ expectations affect their perceptions
How can Top-Down Influences be good?
Efficiency
How can Top-Down Influences be bad?
Error/limit interpretation
What is chemical sense?
They rely on chemical molecules not a form of ‘energy’
What is smell/olfaction?
Receptor sites resemble neurotransmitter binding site.
Odour molecules (odorants) lock into certain sites.
Action potential
Receptors send messages to olfactory area in brain.
linked to amygdala (emotion)
hippocampus (memory)
available early/prenatal (but airborne)
What do we mean when we refer to taste?
Chemical receptors = taste buds - consist of several receptor cells.
about 9,000 taste buds grouped in different regions, which was located on edges & top of tongue, thalamus
prenatal-childhood more
What is taste flavour gustation influenced by?
appearance/palatability
texture
previous experience
What are the 3 dimensions of colour vision?
Hue, brightness, saturation
What is hue?
It is the specific colour perceived, wavelength
What is brightness?
It refers to the intensity of the light energy that’s perceived, amplitude of wave
What is saturation?
It refers to the purity of the colour
What are the theories of colour vision?
Trichromatic theory (Young-Helmholtz)
Opponent-Process theory
Explain afterimages
Dual Process Theory
What is trichromatic theory?
There are 3 types of colour receptors.
Cones most sensitive to blue/purple, green, red wavelengths.
Visual system combines activity from these cells.
Colours are perceived by additive mixture of impulses.
If all are equally activated - white colour is produced
What can’t trichromatic theory explain?
Red-green colour blind individuals shouldn’t be able to perceive yellow (red + green = yellow).
- Afterimages
- state at red - look away you’ll see green (same for blue and yellow)
What is opponent-process theory?
3 cone types; each responds to 3 different wavelengths - opposing pairs.
Red or green, blue or yellow, black or white.
What is explain afterimages?
Stare at certain colour.
neural processes become fatigued,
have ‘rebound’ effect with receptor responding with the opponent opposite reaction
What is Dual Process Theory?
This combines trichromatic & opponent-process theory.
- 3 types of cones sensitive to short (blue), medium (green), and long (red) wavelengths.
- these cones stimulate opponent-process reactions.
- opponent processes occur in ganglion cells, neurons in relay stations & visual cortex
What is the 4 Gestalt Principles?
Similarity, Proximity, Closure, Continuity
What is similarity?
Similar items belong together
What is proximity?
Elements close together belong together
What is closure?
Close open edges: perceive boundaries, fill in gaps
What is continuity?
Elements linked to form a continuous line, pattern
What is depth perception?
Image on the retina is 2 dimensional, but we live in a 3 dimensional world.
- monocular depth cues
- binocular depth cues
What is the interposition of monocular depth cues?
When one object partly blocks view of another, perceive partially blocked object as farther away
What is the linear perspective of monocular depth cues?
Parallel lines known to be the same distance apart appear to grow close together, or converge, as they recede into the distance
What is the relative size of monocular depth cues?
Larger objects perceive as closer, smaller objects as farther away
What is the texture gradient of monocular depth cues?
Near objects appear to have sharply defined textures, objects seem smoother and fuzzier as they recede
What is shadow or shading or monocular depth cues?
When light falls on objects, it casts shadow. can distinguish bulges form indentations by the shadows they cast.
What is motion parallax of monocular depth cues?
When riding in a moving vehicle - look out the side window
- objects close to you appear to be moving faster than those at a distance
- objects very far away, such as the moon and the sun, appear to be stationary.
What is binocular depth cues?
Have 2 eyes for a reason (gives exquisite depth perception)
Based on binocular disparity (2 eyes receive different visual images)
What is illusions?
Incorrect perceptions, provide information about perceptual processes
What does the outer ear do?
Pinna (part you use for earring & sunglasses)
sound enters auditory canal.
causes tympanic membrance (eardrum) to vibrate.
What does the middle ear do?
Vibration cause malleus, incus, stapes (3 tiny bones) to vibrate,
amplify sound more than 30x
cause oval window to move in and out
What does the inner ear do?
Contains cochlea,
houses basilar membrane - which moves an oval window moves (fluid)
contains hair cells = sound receptors
hair cells synapse with auditory nerve
send impulses to auditory relay station thalamus - then to auditory cortex (temporal lobe)
What is tonotopic?
Organization of auditory cortex
- parts of the cochlea map to parts of the cortex
What are the theories of hearing?
Place Theory, Frequency/Temporal Theory
What is Place Theory?
Each individual pitch is determined by the particular spot or place along the basilar membrane of the cochlea that vibrates the most
What is Frequency/Temporal Theory?
Hair cell receptors vibrate (action potentials) the same number of times per second as the sounds that reach them
What is our current understanding of the theories of hearing?
Both theories have flaws and both have some merit, blend of the 2 is accepted now (emphasis on Place-tonotopic)
What is sound location?
Binaural hearing (2 ears) helps localize sound
What is timing of sounds?
Sounds arrive at closest ear first
use differences in arrival time
What is intensity of sounds?
Sound arriving at closest ear will be more intense
use differences in intensities
What are the different types of hearing loss?
Conduction deafness
Nerve deafness
What is conduction deafness?
Involves mechanical system of hearing (e.g. punctured eardrum, loss of function of bones of middle ear)
What is nerve deafness?
Involves damaged receptors/nerve
Exposure to loud sounds can damage hair cells
What is sense of touch?
Touch/pressure, pain, warmth, cold.
Receptors send messages to brain.
Thalamus and somatic sensory cortex.
Pain (Gate control theory)
What is gate control theory?
Fast and slow pathways,
Block
Spine - now brain
What is Kinesthetic sense?
Information from tendons, muscles and joint about
- positions of body parts in relation to each other
- movement of the entire body and/or its parts
What is Vestibular Sense?
Detect movement
- provides information about body’s orientation in space
- receptors in vestibular apparatus of inner ear
