Chapter 4: Sensation + Perception Flashcards
perception
definition
the brain’s interpretation of raw sensory inputs
explain how perception occurs within the brain
the energy from the raw sensory inputs is tranduced/encoded into neural signals + transmitted along neural axons to auditory centers in the temporal lobe of the forebrain
sensation
definition
detection of physical energy by sense organs (eyes, ears, skin, nose, tongue) which then send information to the brain
sensation
example
energy in the form of vibration/sound waves activates specialized auditory receptors in the ears
all conscious experiences drived from physical/chemical information flowing through our senses are ____
perceptions or sensations?
perceptions
when you tickle my back, I get a weird ____
perception or sensation?
perception
illusion
definition
when the way we percieve a stimulus doesn’t match its physical activity
____ first allows us to pick up the signals in our environments + ____ then allows us to assemble these signals into something meaningful
perception or sensation?
sensation, perception
naive realism
definition
the belief that we see the world precisely as it is
is naive realism correct?
no
-the world isn’t precisely as we see it
-we sample only a tiny portion of the world
transduction
definition
the process of converting an external energy/substance into electrical activity wtihin neurons
transduction
example
the neural messages are interpreted as meaningful sounds by the auditory cortex + auditory association areas of the temporal lobe
sense receptor
definition
specialized cell that transduces a specific stimulus
sensory adaptation
definition
for all of our senses, activation is greatest when we first detect a stimulus
for all of our senses, when is activation the greatest?
when we first detect a stimulus
sensory adaptation
example
the initial smell of perfume in a store is super strong, but as you walk around it becomes less strong
absolute threshold
definition
the minimum intensity of a stimulus necessary for it to be detected at least 50% of the time
is absolute threshold the same for every person?
no
-differs from person to person for each sense
-may also vary with psychological conditions
absolute threshold
example
the radio isn’t super loud but goes from none to being able to sense something a little bit
just noticeable difference (JND)
definition
the smallest difference between 2 stimuli that can be detected by an appropriate sense organ
just noticeable difference
example
-when listening to the radio in the car, if you turn the volume from 5 to 7, you can already hear the difference in sound
-however, if it’s between 30 and 32 you can’t sense the difference
-therefore, you sometimes need a bigger difference to detect the distinction between the 2 volumes
weber’s law
definition
-there is a constant proportional relationship between JND + the original stimulus intensity
-therefore, the stronger the stimulus, a bigger change is needed for a change in stimulus intensity to be noticeable
signal detection theory
definition
how we detect stimuli under uncertain conditions
signal-to-noise ratio
definition
it becomes harder to detect a signal as background noise increases
response bias
definition
the tendency to guess wrong/untruthfully when in doubt + under noisy conditions
what does the frequency of false-negatives + false-positives help us measure?
how biased participants are to respond “yes” or “no” in general
true positive
definition
respond yes, stimulus present
false negative
definition
respond no, stimulus present
false positive
definition
respond yes, stimulus absent
true negative
definition
respond no, stimulus absent
even though there are many distinct stimulus energies (light, sound, touch)…
the sensation we experience is determined by the nature of the ____
stimulus or sensory receptor?
sensory receptor
phosphenes
definition
vivid sensations of light caused by pressure on your eye’s receptor cells
where do phosphenes occur in our brain?
cerebral cortex
-doesn’t matter to our brain whether light or touch activated the sensory receptor, our brains react in the same way to either case
what do phosphenes look like?
sparks or similar to the multicolored shapes in a kaleidoscope
what can phosphenes potentially explain?
certain reports of ghosts + UFOs
synesthesia
definition
a remarkable condition in which people experience cross-modal process
synesthesia
example
hearing sounds when seeing colors
why does synesthesia occur?
2 reasons
-crosstalk among different brain regions
-a single brain region may serve double duty
crosstalk in synesthesia
example
-hear high tone with ligher colors + low tone with darker colors
-seeing a pat on someone’s shoulder + feeling the pat on your own shoulder
single brain region serving double duty in synesthesia
example
neurons in the auditory cortex tune to sound + also respond to touch
-if visual stimuli enhanced touch perception
mirror-touch synesthesia
definition
a person experiences the same sensation that another person experiences
-such as touch
lexical-gustatory synesthesia
definition
words are associated with specific tastes/textures
chromesthesia
definition
sounds trigger the experience of color
misophonia
definition
sounds trigger strong emotions such as anger/fear
personification
numbers, letters, or days of the week take on personality characteristics + sometimes have a characteristic appearance
personification
example
-6 might be experienced as a king
-8 might be experienced as a sorcerer
number-form synesthesia
definition
numbers are imagined as mental maps
spatial sequence synesthesia
definition
certain sequences of numbers, dates, or months are perceived as closer/farther in space
psychophysics
definition
the study of how we perceive sensory stimuli based on their physical characteristics
selective attention
definition
process of selecting 1 sensory channel + ignoring/minimizing others
cocktail party effect
definition
if you go to a party + it is loud, you are still able to continue your conversation
exception to cocktail party effect
if you are at a party talking in a group + hear your name being called by someone on the other side of the room, you can still detect that
cocktail party effect is under the category of ____
selective attention
filter theory of attention
definition
views attention as a bottleneck through which information passes
-our mental filter slows down information by enabling us to pay attention to important stimuli + ignore others
inattentional blindness
definition
failure to detect stimuli that are in plain sight when our attention is focused elsewhere
change blindness
definition
failure to detect obvious changes in one’s environment
binding problem
definition
when we percieve an apple, different regions of our brains process different aspects of it
-we don’t really know how our brains manage to combine these diverse pieces of information into a unified whole
light
definition
a form of electromagnetic energy with brightness influenced by the intesnity of the reflected light that reaches our eyes
hue
definition
the color of light
acuity
definition
sharpness of vision
pupil
definition
a circular hole through which light enters the eye
why does the pupil dilate?
to process complex information + attractive faces
cornea
definition
bends light waves to focus image on retina
lens
definition
bends light to fine-tune visual image
where is the lens located?
behind the cornea
lens accomondation
definition
flat or fat
flat lens accomodation
definition
-long, skinny
-lens for distant objects
fat lens accomodation
definition
-short, wide
-lens for nearby objects
retina
definition
has 2 types of receptor cells for seeing light + color
-rods
-cones
rods
definition
-for seeing basic shapes + forms
-long + narrow
-allows us to see in low levels of light
cones
definition
for color vision
dark adaptation
definition
time in the dark before rods regain maximum light sensitivity
photopigments
definition
chemicals that change following exposure to light
rhodopsin
definition
photopigment in rods
what vitamin improves vision + when?
vitamin A
-only improves vision when vision is impaired due to a vitamin A deficiency
fovea
definition
the central portion of the retina
optic nerve
definition
-contains the axons of ganglion cells
-travels from the retina to the rest of the brain
blind spot
definition
-a part of the visual field we can’t see
-a region of the retina containing no rods/sense receptors because axons of ganglion cells push everything else aside
what do blind spots contribute to?
our visual illusion
feature detection
definition
our ability to use certain minimal patterns to identify objects