Biological [Sensation And Perception] (Psychology Subject) Flashcards
Sensation and perception
*sensation is the feeling that results from physical stimulation, perception is the way we organize or experience the sensation
Reception
*takes place when receptors for a particular sense detect a stimulus
Receptive field
*the distinct region of sensory space that can produce a response when stimulated
- found on the body surface and in muscles, joints, eyes, and internal organs
Sensory transduction
*the process in which physical sensation is changed into electrical messages that the brain can understand
- is at the heart of the senses
- signal —> collection —> transduction —> processing —> action
Neural pathways
*path in which electrical information travels to the brain, where the information is understood
Nativist theory
*asserts that perception and cognition are largely innate and genetically based
- humans are born with all their perceptual capacities, though some abilities are not present at birth and develops through maturity
Empiricist theory
*perception is basically learned and develops as the individual adapts to their environment
Structuralist theory
*perception is the sum total of sensory input: one can understand the mind by understanding its basic components
- bottom-up processing—starts with sensory data and works upward to brain’s integration of that data
Gestalt psychology
*people tend to see the world in terms of organized wholes rather than constituent parts
- top-down processing—starts with higher-level cognitive processes and works downward to sensory information
Absolute threshold
*minimum amount of a stimulus that can be detected 50% of the time
Differential threshold
*minimum difference that must occur between two stimuli, in order for them to be perceived as having different intensities
- also known as just noticeable difference (JND)
- E. H. Weber
Terminal threshold
*upper limit above which the stimuli can no longer be perceived
- i.e., lowest pitch sound that a human can hear is absolute threshold, the highest pitch is the terminal threshold
Psychophysics
*the study of the quantitative relations between psychological sensations and physical stimuli
- Gustav Fechner’s “Elements of Psychophysics”
Weber’s law
*a stimulus needs to be increased by a constant fraction of its original value in order to be perceived as noticeably different
- applies to all senses but only to a limited range of intensities
- K (the constant fraction) = Δ I (increase in intensity needed for jnd) / I (original intensity)
Fechner’s law
*the strength of a stimulus must be significantly increased to produce a slight difference in sensation
- S (sensation strength) = k log R (a logarithm of the original intensity)
J. A. Swet’s Theory of Signal Detection (TSD)
*subjects detect stimuli not only because they can but also because they want to
- factors in motivation
- explains why subjects respond inconsistently; partly motivated by rewards and costs in detection (response bias)
False alarm
*you detect a stimulus that is not there
Hit
*correctly sensing a stimulus
Miss
*failing to detect a present stimulus
Correct rejection
*rightly stating that no stimulus exists
Receiver operating characteristic (ROC) curves
*graphical representations of a subject’s sensitivity to a stimulus
Light
*composed of photons and waves measured by brightness and wavelengths
Hue
*the dominant wavelength of light
- also known as color
Brightness
*the physical intensity
Cornea
*the clear protective coating on the outside of the eye
Lens
*located behind the cornea
Ciliary muscles
*Allows lens to bend (accommodate) in order to focus an image of the outside world onto the retina
Retina
*receives light images from the lens
- located on the back of the eye
- composed of about 132 million photoreceptor cells and of other cell layers that process information
Receptor cells
*responsible for sensory transduction (converting image into an electrical message the brain can understand)
— occurs through chemical alteration of photopigments
- rods and cones
Rods
*sensitive to dim light and used for night vision
- concentrated along sides of the retina, important for peripheral vision
Cones
*concentrated in the center of the retina (area called the fovea)
- sensitive to color and daylight vision
- sees better than rods because there are fewer cones per ganglion cell than rods per ganglion cell
Fovea
*the area of the retina with the greatest visual acuity (best at seeing fine details)
Horizontal, bipolar, and amacrine cells
*after light passes through receptors, travels through cells till information heads to the ganglion cells, which make up the optic nerves
How eyes connect to the cerebral cortex
- through a visual pathway
— consists of one optic nerve connecting each eye to the brain
— along pathway is an optic chias in which half of the fibers from the optic nerve of each eye cross over and join the optic nerve from the other eye; pathways are 50% crossed - a stimulus in the left visual field is processed in the right side of the brain, and vice versa
- after optic chiasm, info travels through the striate cortex to the visual association areas of the cortex
Opponent-color or opponent-process
*theory for color vision; suggests that two types of color-sensitive cells exist: cones that respond to blue-yellow colors and cones that respond to red-green
- when one color of the pair on a cone is stimulated, the other is inhibited
- Ewald Hering
- seems to be at work in the lateral geniculate body
Trichromatic theory (component theory)
*there are three types of receptors in the retina: cones that respond to red, blue, or green
- Thomas Young and Herman von Helmholtz
- seems to be at work in the retina
Lateral inhibition
*allows the eye to see contrast and prevents repetitive information from being sent to the brain
- once one receptor cell is stimulated, the others nearby are inhibited
David Hubel and Torsten Wiesel
- discovered that cells in the visual cortex are so complex and specialized that they respond only to certain types of stimuli
- I.e., some cells responsive only to vertical lines, some respond only to right angles, etc
Visual field
*refers to the entire span that can be perceived or detected by the eye at any given moment
Figure and ground relationship
*refers to the relationship between the meaningful part of a picture (the figure) and the background (the ground)
Depth perception
*has monocular and binocular cues
Binocular disparity
- our eyes view objects from two slightly different angles, which allows us to create a three-dimensional picture
- the most important depth cue
Apparent size
*gives us clues about how far away an object is if we know about how big the object should be
Interposition
*shows which objects are closer
Linear perspective
*gained by features we are familiar with, such as two seemingly parallel lines that converge with distance
Texture gradient
*the way we see texture or fine detail differently from different distances
- the closer the object, the more coarse and distinct the features appear
- more distant objects appear finer and smoother in texture
Motion parallax
*the way movement is perceived through the displacement of objects over time, and the way this motion takes place at seemingly different paces for nearby or faraway objects
Eleanor Gibson and Richard Walk
*developed the visual cliff apparatus to study whether depth perception is innate
Afterimages (McCollough effect)
*perceived because of fatigued receptors
- explains dark afterimage after staring at a white light
Dark adaptation
*the result of regeneration of retinal pigment
mental set
*framework for assessing a problem and identifying solutions based on our experience: we tend to try what has worked in the past
Pragnanz
*overarching Gestalt idea that experience will be organized as meaningful, symmetrical, and simple whenever possible
Closure (Gestalt)
*tendency to complete incomplete figures
Proximity (Gestalt)
*tendency to group together items that are near each other
Continuation or good continuation (Gestalt)
*tendency to create a whole or detailed figures based on our expectations rather than what is seen
Similarity (Gestalt)
*tendency to group together items that are alike
Symmetry (Gestalt)
*tendency to group together items that are alike
Constancy (Gestalt)
*tendency of people to perceive objects in the way that they are familiar with them, regardless of changes in the actual retinal image
- size constancy—knowing that an elephant is large no matter how it might appear
- color constancy—knowing the color of an object even with tinted glasses on
Minimum principle
*tendency to see what is easiest or logical to see
Ambiguous figures
*can be perceived as two different things depending on how you look at them
Figure-ground reversal patterns
*ambiguous figures; can be perceived as two different things depending on which part you see as the figure and which part you see as the background
- I.e., the Rubin vase
Impossible objects
*objects that have been drawn and can be perceived but are geometrically impossible
Multistability
*perception of an object can alternate between two or more possible interpretations
- I.e., our perception of an object flips from one “stable” interpretation to another
Moon illusion
*shows how context affects perception
- moon looks larger over the horizon because the horizon contains visual cues that make the Moon appear more distant
Phi phenomenon
*the tendency to perceive smooth motion
- explains why motion is inferred when there actually is none
— use of flashing lights or rapidly shown still-frame pictures, such as in the perception of cartoons (apparent motion)
Müller-Lyer illusion
- two horizontal lines of equal length appear unequal because of the orientation of the arrow marks at the end
- inward facing arrowheads make a line appear shorter than another line of the same length with outward facing arrowheads
- the most famous visual illusion
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Ponzo illusion
*occurs when two horizontal lines of equal length appear unequal because of two vertical lines that slant inward
Autokinetic effect
*the way that a single point of light viewed in darkness will appear to shake or move due to the constant movements of our own eyes
Purkinje shift
*the way that perceived color brightness changes with the level of illumination in the room
- with lower levels of illumination, extremes of the color spectrum (i.e., red) appear less bright
Pattern recognition
- explained by template matching and feature detection
- to pick the letter O out of a page of letters, we would concentrate only on letters with rounded edges and then look for one to match a typical O
Robert Frantz
- found that infants prefer relatively complex and sensical displays
Amplitude
*physical intensity of a sound wave
- determines loudness
Frequency
*the pace of vibrations or sound waves per second for a particular sound
- determines pitch
- low frequency perceived as low pitch/tone, and vice versa
- measured in hertz (Hz)
— humans best hear frequencies around 1,000 Hz
Timbre
*comes from the complexity of the sound wave
Outer ear
*consists of the pinna and the auditory canal
- vibrations from sound move down canal to the middle ear
Middle ear
*begins with the tympanic membrane (eardrum)
- behind membrane are the ossicles (three small bones), last of which is the stapes
- sound vibrations bump against the tympanic membrane, causing the ossicles to vibrate
Inner ear
*responsible for hearing and balance
- begins with the oval window, which is tapped upon by the stapes
- cochlea (contains ear parts for hearing; basilar membrane, organ of corti) is then activated
— movement on the basilar membrane is called the traveling wave
- the vestibular sacs are sensitive to tilt and provide our sense of balance
- receptor cells activate nerve cells that change information into an electrical message the brain can process
— consists of the olivary nucleus, the inferior follicular, and the medial geniculate body
Herman von Helmholtz
- place-resonance theory of sound perception
— different parts of the basilar membrane respond to different frequencies
Sound localization
*the degree to which one of our ears hears a sound prior to and more intensely than the other can give information about the origin of the sound
- high-frequency sounds are localized by intensity differences; low-frequency sounds are localized by phase differences
Dichotic presentation
*used in studies of auditory perception and selective attention
- subject is presented with a different verbal message in each ear; subjects asked to shadow (repeat) one of the messages to ensure that the other message is not consciously attended to
Olfaction
*sense of smell
- olfactory bulb lies at the base of the brain and takes messages from hair receptors in the nostrils
- connected to memory and perception of taste
Gustation
*act of tasting
- sweet, bitter, sour, salty, and umami
- saliva mixes with food so flavor can flow easily into the tongue’s taste receptors (taste buds, papillae)
Somatosenses
*gives info about the physical body apart from the major sensory organs
- provides sensory data concerning touch, heat, pain, pressure, balance, vibration, orientation, and muscle movement
Cutaneous/tactual
*relating to touch
- human skin senses touch, pain, cold, and warmth
Free nerve endings
*detects pain and temperature changes
Meissner’s corpuscles
*receptors in skin that detect touch or contact
Pacinian corpuscles
*touch receptors that respond quickly to displacements of skin
Two-point threshold
*distance between two points at which the individual recognizes they are being touched by two objects rather than one
- size of threshold determined by the density and layout of nerves in the skin
Physiological zero
*the temperature that is sensed as neither warm nor cold
Ronald Melzack and Patrick Wall’s Gate Control Theory of Pain
*looks at pain as a process rather than a simple sensation governed in one center of the brain
- pain perception is related to the interaction of small and large nerve fibers that run to and from the spine
- pain may or may not be perceived depending on different factors, like cognition
Phantom limb pain
*occurs when amputees feel sensations of pain in limbs that have been amputated and no longer exists
Endorphins
*neuromodulators that kick in to reduce or eliminate the perception of pain
Orienting reflex
*the tendency to turn toward an object that has touched you
Vestibular sense
*allows us to orient ourselves in space and maintain balance
- main components found in the inner ear in the vestibular labyrinth
Vestibular labyrinth
*a series of interconnected structures continuous with the cochlea
- contains three tubes called semicircular canals, which detect head motion and help to maintain equilibrium
Kinesthetic sense
*involves awareness of the body’s movement
- deals with bodily movement
- behavioral component; allows us to learn complex physical actions like performing a dance routine
Spindles
*tiny receptors in the muscles throughout the body
- provides “muscle memory”; allowing us to sense how our limbs are moving in space without visual confirmation
Proprioception
*refers to the cognitive awareness of where our bodies are in space at any given time
- deals with sensing one’s own bodily position in space
Selective attention
*the process of tuning in to something specific while ignoring all other stimuli in the background
Spotlight model
*humans focus on one particular task while all other tasks remain in the background until the spotlight focuses on a different task
- William James; attention has a focus (primary area attended to), fringe (the periphery) , and a margin (the limit)
Donald Broadbent’s filter model of attention
*any information not attended to is filtered out and decays
- explains why we’re not constantly bombarded with sensory inputs
- sensory input goes from our sensory stores through a selective filter, which blocks unattended messages
- only information attended to makes it into our working memory
- attended message—>sensory store—>selective filter—>higher-level processing—>working memory
Anne Treisman’s attenuation model of attention
- cocktail party effect; a person involved in a conversation can detect their name or something equally salient from across a crowded room
- sensory input flows into sensory stores and through an attenuating filter, turning the volume down or up on the information
- rather than decaying, unattended information goes through higher level processing and into working memory, so it’s available on this other channel if need be
Divided attention (multitasking)
*occurs when a person’s attention is split among multiple tasks
- when people multitask, they’re more likely to make mistakes and/or move more slowly through their task because of enormous cognitive load (amount of mental effort involved)
- addressed by resource model of attention (humans have a limited amount of attention at any given time)
Simulations
*use perceptual cues to make artificial situations seem real
Subliminal perception
*the perceiving of a stimulus that one is not consciously aware of
- I.e., the unattended message in dichotic presentation or visual information that is briefly presented
Osmoreceptors
*deals with thirst
