Chapter 5 - sensation and perception Flashcards
sensation
is the process through which the senses detect visual, auditory, and other sensory stimuli and transmit them to the brain
perception
is the process by which sensory info is actively organized and interpreted by the brain
thresholds
how much stimulation has to be out there before we can detect that it is there
sensory transduction
converting info in environment into neural applications
absolute threshold
- Difference between not being able to perceive a stimulus and being able to just barely perceive it
- The minimum amount of sensory stimulation that can be detected 50% of the time
difference threshold
the minimal difference between two stimuli necessary for detection of a difference between the two.
JND example
Radiology example
○ Have to be able to determine between shading in order to detect the “tumour”
-Notice it’s darker or lighter in certain areas
inequality threshold
variation across senses
Sensory Adaptation- “not seeing”
○ Become less sensitive to unchanging sensory stimulus overtime
○ Automatic process
○ Allows us to shift attention
two types of processing
bottom up and top down
bottom up
○ Individual components of stimulus detected by sensory receptors
Bits of info transmitted to areas of the brain to be combined and assembled into a unified whole.
Top down
○ Past experiences 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
Perceptual Set:
where individuals’ expectations affect their perceptions
Anatomy of Smell
○ Olfactory epithelium
○ Olfactory receptor neurons
○ Olfactory bulb
Taste: Sensation
Chemical receptors/sensation-independent, “Taste”
○ Chemical receptors = taste buds- consist of several receptor cells
○ Ab 9,000 taste buds grouped in different regions
○ Located on edges & top of tongue
○ Thalamus
○ Prenatal-childhood more
Neuro gustatory
study of taste and smell etc
Taste Flavour Gustation Influenced by
○ Appearance/ palatability
○ Texture
○ Previous experience
parts of the eye
○ Cornea ○ Lens ○ Retina ○ Rods ○ Cones ○ Fovea ○ Optic Nerve
optic nerve
○ Perceive small part of electromagnetic (EM) spectrum
○ Light waves measured in nanometers (billionths of meter)
Three dimensions of colour vision
Hue is the specific colour perceived, wavelengths
○ Brightness refers to the intensity of the light energy that is perceived, ampitutde of a wave
○ Saturation refers to the purity of the colour
Trichromatic theory (young-helmholtz)
the manner in which the visual system gives rise to the phenomenological experience of color.
Opponent- Process theory (Herring, 1870)
○ Three cone types ○ Each responds to two different wavelengths-opposing pairs ○ Red or green ○ Blue or yellow ○ Black or white
Dual Process Theory
○ Combines trichromatic & opponent-process theories
current view of colour
○ 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
dual process theory
a metatheoretical framework which posits that the conflict between two types of cognitive processes can explain the majority of human decision-making patterns
Figure-ground
○ Simplest form of organization
○ Have foreground and background
○ Figure
- Distinct shape
-More striking
○ Figure-ground distinction can be ambiguous
-§ Is the idea behind camouflageProximity
Elements close together belong together
Continuity
Elements linked to form a continuous line, pattern
Closure
Close open edges; perceive boundaries; fill in gaps
types of constancy
size constancy, shape constancy, brightness constancy
Size constancy
○ Ex. Standing on the road, a car is approaching and getting larger, you move out of the way
Shape constancy
○ Changing perception of shape
-Ex. If something looks similar to its original shape, we still see the same thing
Brightness constancy
Colour, whether you’re in light or dark, far or close
Monocular depth cues
interposition, linear perspective, relative size, texture gradient, shadow/shading, motion parallax
Interposition
-when one object partly blocks view of another, perceive partially blocked object as farther away
linear perspective
○ parallel lines known to be the same distance apart appear to grow closer together, or converge as they recede into the distance
Relative size
- larger objects perceived as being closer, smaller objects as being farther away
Texture gradient
- near objects appear to have sharply defined textures, objects seem smoother and fuzzier as they recede
Shadow/Shading
-when light falls on objects, it casts shadows. Can distinguish bulges from indentations by the shadows they cast
Motion parallax
- when riding in a moving vehicle, look out the window
ex. Objects closest (trees, grass) appear to move faster than those in the distance (moon/sun seem stationary)
binocular disparity
§ 2 eyes receive different visual images (ex. Close one eye with one finger in front of you)
Binocular depth cues
○ Depth perceived with 2 eyes (have 2 for a reason)
§ Gives exquisite depth perception
○ Visual depth cues that depend on both eyes working together
Convergence
Feedback from ocular muscles when focusing on something distant and then close
2 characteristics for sound
frequency, amplitude
Frequency
- # of cycles per second (Hz per second we hear
- Related to pitch of sound we hear (2000 - 5000 Hz)
amplitude
- Amount of compression + expansion of molecules
- Related to ‘loudness’ we perceive
- Measured in decibels (dB)
- Normal conversation about 65dB; rock band about 120 dB
Outer ear
○ Pinna (part you use for earrings + sunglasses)
§ Directs sound into ear canal
○ Auditory canal (where sound enters)
Eardrum (sound causes it to vibrate)
Middle
-Ossicles
- Vibration causes malleus, incus, stapes (3 tiny bones) to vibrate
- Amplify sound more than 30X
- Cause oval window to move in and out
inner
-Cochlea
-Houses basilar membrane - which moves as 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)
-Tonotopic
□ Organization of auditory cortex
-Parts of cochlea map to parts of cortex
Place theory
each individual pitch is determined by particular spot/place along basilar membrane of cochlea that vibrates the most
Frequency/Temporal Theory
- hair cell receptors vibrate (action potentials) the same number of times per second as the sounds that reach them
current understanding of both theories (FTT & PT)
- Both theories have flaws and both have some merit
* Blend of the two is accepted now (emphasis on place-tonotopic)
Timing of sounds
○ Sounds arrive at closest ear first
○ Use differences in arrival time
Conduction deafness
○ Involves mechanical system of hearing
-Ex. Punctured eardrum, loss of function of bones of middle ear
Nerve deafness
- Involves damaged receptors/nerve
- Exposure to loud sounds can damage hair cells
Pain
○ Gate control theory
- Fast and slow pathways - Block - Spine : now brain
Intensity of sound
○ Sound arriving at closest ear will be more intense
○ Use differences in intensities
Kinesthetic sense
-info from tendons, muscles and joints about
○ Position of body parts in relation to each other
○ Movement of the entire body and/or its parts
Vestibular sense
- detects movement
- Provides info about body’s orientation in space
- Receptors in vestibular apparatus of inner ear
Critical periods
age where experiences MUST occur
Sensitive periods
optimal age range (where it should occur, but can be caught up later)
Continuity vs discontinuity
-How you are at one point in your life significantly changes … you can never go back (discontinuous)
visually mapping change (5)
no change, continuous, stages, inverted U-shape, U-shape function
two types of research design
longitudinal and cross-section
Longitudinal
-Test same cohort at different times
Ex. Gifted people were observed from early life to 60yrs old
Cross-section
○ Compare different ages at the same time
pros and cons :longitudinal
Pros
- Follow someone, you know what their life looked like before and after a change
- Real conclusions about development
Cons
- Time consuming
- People drop out (move, die)
- Generalizability (all people? Just this group?)
- Same people (reduces variability across samples)
Pros and cons : cross-section
○ Pros § Data from many age groups § Fast ○ Con: cohort effects § Different experiences, cultural changes, environmental changes □ Ex. iPad, cloud now prevalent ○ Solution
Genotype
genetic “blueprint” and genetic expression
Phenotype
expressed, what you visually see
Chromosomes
strands of DNA
Alleles
genes that align
○ Homozygous (same for both parents)
○ Heterozygous (different from each parent)
three stages of prenatal development
- germinal stage
- embryonic stage
- fetal stage
germinal
-Zygote (ab 1 week)
Blastocyst attaches to uterine wall (placenta)
embryonic stage
- 2nd - 8th week
- Placenta + umbilical cord develop - basic systems
○ Fetal stage
- Begins 9th week
- Refinement, growth
- Brain development
3 environmental influences
teratogens, maternal malnutrition, maternal stress
Teratogens
§ Environmental agents that can cause abnormal development
□ When soldiers went away and got a virus, brought it back, and it infected children
□ Radiation
□ Morning after pill at one point caused hands to be underdeveloped
Maternal malnutrition
§ Miscarriage, premature birth, stillbirth impaired brain development
□ Folic acid is needed within the firs 28 days
□ Some moms do not have access to the most nutritious foods
Maternal stress (stress hormones)
-Premature birth, infant irritability, attentional deficits
Bad mental health
3 types of physical development
Maturation, Cephalocaudal principle, Proximodistal Principle
Cephalocaudal principle
- Development proceeds from head to foot
- Head is large
Proximodistal Principle
○ Development proceed from innermost to outermost
-Arm before fingers
absolute pitch
the ability to recognize or produce any note on a musical scale.
ageusia
inability to taste.
anosmia
inability to smell.
basilar membrane
structure in the cochlea where the hair cells are located.
cones
photoreceptors responsive to colours.
endorphins
belong to a naturally occurring class of opiates that reduce pain in the nervous system.
endorphins
belong to a naturally occurring class of opiates that reduce pain in the nervous system.
fovea
centre of the retina, containing only cones, where vision is most clear.
free nerve endings
sensory receptors that convert physical stimuli into touch, pressure, or pain impulses.
gate control theory of pain
theory that certain patterns of neural activity can close a “gate” to keep pain information from travelling to parts of the brain where it is perceived.
gustatory sense
our sense of taste.
hair cells
sensory receptors that convert sound waves into neural impulses.
Meissner’s corpuscles
sensory receptors that convert physical stimuli about sensory touch on the fingertips, lips, and palms.
Merkel’s discs
sensory receptors that convert information about light to moderate pressure on the skin.
monocular cues
visual clues about depth and distance that can be perceived using information from only one eye
odorants
airborne chemicals that are detected as odours.
olfactory bulb
the first region where olfactory information reaches the brain on its way from the nose.
olfactory receptor neurons
sensory receptor cells that convert chemical signals from odorants into neural impulses that travel to the brain.
ossicles
tiny bones in the ear called the maleus (hammer), incus (anvil), and stapes (stirrup).
oval window
a membrane separating the ossicles and the inner ear, deflection of which causes a wave to form in the cochlea.
Pacinian corpuscles
sensory receptors that respond to vibrations and heavy pressure.
papillae
bumps on the tongue that contain clumps of taste buds.
perceptual constancies
our top-down tendency to view objects as unchanging, despite shifts in the environmental stimuli we receive.
perceptual set
readiness to interpret a certain stimulus in a certain way.
retina
a specialized sheet of nerve cells in the back of the eye containing the sensory receptors for vision.
retinal disparity
the slight difference in images processed by the retinas of each eye.
rods
photoreceptors most responsive to levels of light and dark.
Ruffini’s end-organs
sensory receptors that respond to heavy pressure and joint movement.
sensation
the act of using our sensory systems to detect environmental stimuli.
sensory adaptation
the process whereby repeated stimulation of a sensory cell leads to a reduced response.
sensory transduction
the process of converting a specific form of environmental stimuli into neural impulses.
sound waves
vibrations of the air in the frequency of hearing.
taste buds
clusters of sensory receptor cells that convert chemical signals from food into neural impulses that travel to the brain.
tonotopic map
representation in the auditory cortex of different sound frequencies.
transduction
process that involves converting stimulus energy into neural impulses that can be interpreted by the brain.
tympanic membrane
the ear drum.
