Chapter 4 Flashcards
What’s the difference between sensation and perception?
sensation = simple stimulation of sense organ
perception occurs after sensation registers in nervous system; organizes, identifies, and interprets a sensation to form mental representation
What is transduction?
when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
Define psychophysics
methods that measure the strength of a stimulus and the observers sensitivity to that stimulus
What is the absolute threshold in psychophysics?
the minimal intensity needed to just barely detect a stimulus in 50% of trials
What is the just noticeable difference? Describe relation to human perceptual system
the minimal change in a stimulus that can just barely be detected; humans are better at detecting changes in stimuli i.e. parents deciphering certain cries
T/F The Just Noticeable difference is a fixed quantity
FALSE; depends on how intense stimuli being measured and on sense being measured
What is Weber’s law?
The JND of a stimulus is a constant proportion despite variations in intensity; envelope vs. package
What are the 2 things signal detection theory says about how we respond to stimuli?
the response to stimuli depends on both
1) the person’s sensitivity to the stimuli in the presence of noise and
2) the person’s response criticism i.e.their internal decision making (more often saying they saw light just to be safe)
What are examples of sensory adaptation?
bakery smell fades, cold water not noticeable, bathroom light at night doesnt require squinting
What are the benefits of sensory adaption?
can focus on change in stimuli
What is visual acuity?
the ability to see fine detail
What 3 characteristics of light do humans perceive?
length–> color
amplitude–> brightness
purity–> saturation
Light reflected from an objects surface enters the eyes via the transparent _____, bending to pass through the _____ at the center of the _____. Behind the ____, the thickness and shape of the ____ adjust to focus light on the _____, where the image appears upside down and backward. Vision is clearest at the ______
cornea; pupil; iris; iris; lens; retina; fovea
Muscles change the shape of the lens to focus objects at different distances, a process called _____
accomodation
Cones detect ___/____ ___ and rods detect ____ ___
color, fine detail; night vision
There are no ___ on the fovea
rods
What do the bipolar cells do?
collect neural signals from the rods and cones and transmit them to the outermost layer of the retina
What do the retinal ganglion cells do?
organize signals sent by bipolar cells and send them to brain
What composes the optic nerve?
retinal ganglion cell axons
Why is there a blind spot in the visual field?
the optic nerve leaves the eye through a hole in the retina, and this hole has no rods and cones
What is area V1?
the part of the occipital lobe that contains the primary visual cortex
What three types of cones are there?
long-wavelength (red)
medium-wavelength (green)
short-wavelength (blue)
Ventral stream travels from occiptal lobe to ____ lobe; “___” pathway
dorsal stream travels up from occipital lobe to ____ lobe; “__” pathway
temporal; what
parietal; how
What is the binding problem in perception?
how the brain links features together so that we see unified objects in our visual world rather than free-floating or miscombined features
What is an illusory conjunction?
perceptual error where brain incorrectly combines features of multiple objects i.e. red A, black 8 experiment
What is a feature-integration theory?
focused attention is not required to detect the individual features that make up a stimulus, such as the color, shape, size, and location of letters, but is the glue required to bind those individual features together
What is perceptual consistency?
even as aspects of sensory signals change, perception remains constant
Gestalt groupings:
- simplicity
- closure
- continuity: edges w/same orientation are grouped together
- similarity
- proximity
- common fate: moving together, same object
According to image-based recognition theories, what is a template?
a mental representation that can be directly compared to a viewed shape in the retinal image
What is the theory called that proposes we deconstruct objects?
parts-based object recognition
What are some monocular depth cues?
- familiar size i.e. office chair lady
- linear perspective i.e. railroad tracks
- texture gradient i.e. cracked desert sand
- interposition i.e. apple blocking orange is closer
- relative height in image i.e. flowers are lower than mountain
What is apparent motion?
perception of movement as a result of alternating signals appearing in rapid succession in different locations i.e. Vegas sign
3 qualities of sound
frequency = pitch amplitude = loudness complexity = timbre
What is the cochlea?
fluid-filled tube that is the organ of auditory transduction
Cochlea is divided along its length by what?
basilar membrane, a structure in the inner ear that undulates when vibrations from the ossicles reach the cochlear fluid
Movement of the basilar membrance stimulates what?
hair cells, specialized auditory receptor neurons embedded in the basilar membrane
What portion of the temporal lobe contains the primary auditory cortex?
a1
What is the place code?
(high frequencies) diff frequencies stimulate neural signals at specific places along basilar membrane
What is temporal code?
registers relatively low frequencies via the firing rate of action potentials entering the auditory nerve
