Sensing and Perceiving Flashcards
sensation
awareness resulting from the stimulation of a sense organ
perception
the organization and interpretation of sensations
transduction
the conversion of stimuli detected by receptor cells to electrical impulses that are then transported to the brain
Psychophysics
the branch of psychology that studies the effects of physical stimuli on sensory perceptions and mental states
Gustav Fechner
the first to study the relationship between the strength of a stimulus and a person’s ability to detect the stimulus.
absolute threshold of a sensation
the intensity of a stimulus that allows an organism to just barely detect it.
Signal detection analysis
a technique used to determine the ability of the perceiver to separate true signals from background noise
hit
correctly say “ yes‖ when there was a sound
false alarm
when you respond “ yes‖ to no signal. In the other two cases you respond “no‖
miss
(saying “no‖ when there was a signal)
correct rejection
(saying “ no‖ when there was in fact no signal
sensitivity
refers to the true ability of the individual to detect the presence or absence of signals.
response bias
refers to a behavioral tendency to respond “yes‖ to the trials, which is independent of sensitivity.
difference threshold/ just noticeable difference [JND]
the change in a stimulus that can just barely be detected by the organism
Ernst Weber law
just noticeable difference of a stimulus is a constant proportion of the original intensity of the stimulus
subliminal stimuli
events that occur below the absolute threshold and of which we are not conscious. It can influence our judgments and behavior, at least in the short term. Making someone buy something just because you mention it over and over again, however the effectiveness of it depends on people and situations.
blindsight
a condition in which people are unable to consciously report on visual stimuli but nevertheless are able to accurately answer questions about what they are seeing.
electromagnetic energy;
pulses of energy waves that can carry information from place to place
cornea
a clear covering that protects the eye and begins to focus the incoming light
pupil
a small opening in the center of the eye.
lights travel
cornea, pupil, lens, retina, rods and cones, bipolar cells, ganglion cells, optic nerve, thalamus, brain
iris
surrounds the pupil, it’s the colored part of the eye that controls the size of the pupil by constricting or dilating in response to light intensity
lens
a structure that focuses the incoming light on the retina, the layer of tissue at the back of the eye that contains photoreceptor cells
visual accommodation
the process of changing the curvature of the lens to keep the light entering the eye focused on the retina
nearsighted
if the focus is in front of the retina
farsighted
when the focus is behind the retina we say that the person is
optic nerve
a collection of millions of ganglion neurons that sends vast amounts of visual information, via the thalamus, to the brain
Rods
visual neurons that specialize in detecting black, white, and gray colors
Cones
visual neurons that are specialized in detecting fine detail and colors.
fovea
the central point of the retina, where the cones are located
blind spot
the hole where no photoreceptor cells at the place where the optic nerve leaves the retina
feature detector neurons
specialized neurons, located in the visual cortex, that respond to the strength, angles, shapes, edges, and movements of a visual stimulus. Helps us recognize objects, and some neurons respond selectively to faces and other body parts.
hue
The shade of a color, the length of the wave. longer wavelengths are red and shorter wavelengths are blue/ violet
brightness
intensity or height of the wave (bigger or more intense waves are perceived as brighter).
Hermann von Helmholtz
theorized that color is perceived because the cones in the retina come in three types
Young-Helmholtz theory, known as the opponent-process color theory,
proposes that we analyze sensory information not in terms of three colors but rather in three sets of “ opponent colors‖: red-green, yellow-blue, and white-black. He’s saying that some of the colors are inhibited. So when we see green, we are actually seeing other colors, kind of reflecting
gestalt
a meaningfully organized whole. “Seeing more tahn the sum of the parts”. Principles include: figure and ground, similarities, proximity, continuity, closure
Figure and ground
We structure input such that we always see a figure (image) against a ground
Similarity
Stimuli that are similar to each other tend to be grouped together
Proximity
We tend to group nearby figures together
Continuity
We tend to perceive stimuli in smooth, continuous ways rather than in more discontinuous ways
Closure
We tend to fill in gaps in an incomplete image to create a complete, whole object.
Depth perception
the ability to perceive three-dimensional space and to accurately judge distance. We learn this through experience
Binocular depth
depth cues that are created by retinal image disparity—that is, the space between our eyes, and thus which require the coordination of both eyes
convergence
the inward turning of our eyes that is required to focus on objects that are less than about 50 feet away from us
accommodation
help determine depth it comes in handy when threading a needle or tying shoelaces, it is far less effective when driving or playing sports.
Monocular depth
depth cues that help us perceive depth using only one eye. Such as position, relative size, linear perspective, light and shadow, interposition, aerial perspective
Aerial perspective
Objects that appear hazy, or that are covered with smog or dust, appear farther away.
Interposition
When one object overlaps another object, we view it as closer.
Light and shadow
The eye receives more reflected light from objects that are closer to us. Normally, light comes from above, so darker images are in shadow.
Linear perspective
Parallel lines appear to converge at a distance.
Relative size
Assuming that the objects in a scene are the same size, smaller objects are perceived as farther away.
Position
We tend to see objects higher up in our field of vision as farther away.
beta effect
the perception of motion that occurs when different images are presented next to each other in succession
the phi phenomenon
perceiveing a sensation of motion caused by the appearance and disappearance of objects that are near each other
Vision
the process of detecting the electromagnetic energy that surrounds us.
frequency of the sound wave
the number of waves that arrive per second
pitch
the perceived frequency of a sound. Longer sound waves have lower frequency and produce a lower pitch, whereas shorter waves have higher frequency and a higher pitch
amplitude
height of the sound wave, determines how much energy it contains and is perceived as loudness (the degree of sound volume)
decibel
the unit of relative loudness
pinna
the external and visible part of the ear, which is shaped like a funnel to draw in sound waves and guide them into the auditory canal.
the tympanic membrane (or eardrum),
tightly stretched, highly sensitive membrane which vibrates with the waves.
middle ear
three tiny bones, known as the ossicles—the hammer (or
malleus), anvil (or incus), and stirrup (or stapes)—
cochlea,
a snail-shaped liquid-filled tube in the inner ear
hearing pathway
Sound waves enter the outer ear (the pinna) and are sent to the eardrum via the auditory canal. The resulting vibrations are relayed by the three ossicles, causing the oval window covering the cochlea to vibrate. The vibrations are detected by the cilia (hair cells) and sent via the auditory nerve to the auditory cortex.
cilia
the fibers on top of the hair cells within the cochlea. They are sensitive and can detect movements
Conductive hearing loss
caused by physical damage to the ear (such as to the eardrums or ossicles) that reduce the ability of the ear to transfer vibrations from the outer ear to the inner ear
Sensorineural hearing loss
which is caused by damage to the cilia or to the auditory nerve, is less common overall but frequently occurs with age
tinnitus
a ringing or a buzzing sensation, after being exposed to loud sounds have very likely experienced some damage to their cilia
The frequency theory of hearing
suggests that as a sound wave’s pitch changes, nerve impulses of a corresponding frequency enter the auditory nerve
The place theory of hearing
suggests that we hear different pitches because different areas of the cochlea respond to higher and lower pitches.
proprioception
the ability to sense the position and movement of our body parts.
the vestibular system and the semicircular canals
a set of liquid-filled areas in the inner ear that monitors the head’s position and movement, maintaining the body’s balance.
Gate control theory
explains how large and small neurons work together to transmit and regulate the flow of pain to the brain.
McGurk effect
an error in perception that occurs when we misperceive sounds because the audio and visual parts of the speech are mismatched
synesthesia
an experience in which one sensation (e.g., hearing a sound) creates experiences in another (e.g., vision).
selective attention
the ability to focus on some sensory inputs while tuning out others.
cocktail party phenomenon
shows us that although selective attention is limiting what we processes, we are nevertheless at the same time doing a lot of unconscious monitoring of the world around us—you didn’t know you were attending to the background sounds of the party, but evidently you were
sensory adaptation
a decreased sensitivity to a stimulus after prolonged and constant exposure.
saccades
thousands of tiny movements. Our eyes take in all of these changes to keep it from undergoing sensory adaptation where the image can become bored and your mind will start thinking that it is not there.
perceptual constancy
The ability to perceive a stimulus as constant despite changes in sensation, ie the swinging door
Illusions
occur when the perceptual processes that normally help us correctly perceive the world around us are fooled by a particular situation so that we see something that does not exist or that is incorrect
Mueller-Lyer illusion
The line segment in the bottom arrow looks longer to us than the one on the top, even though they are both actually the same length
Ponzo illusion
Seeing one line as being longer than the other (in railroad picture) caused by a failure of the monocular depth cue of linear perspective: Both bars are the same size even though the top one looks larger
Cognitive illusions
examples of how our expectations can influence our perceptions
