Sensation and Perception Flashcards
Psychophysics
The study of the relationship between physical energy and psychological experiences.
Stimulus
A change in the environment that can be detected by sensory receptors.
Absolute Threshold
The weakest level of a stimulus that can be correctly detected at least half of the time.
Signal Detection Theory
Maintains that minimum threshold varies with fatigue, attention, expectations, motivation, emotional distress, and from one person to another.
Difference Threshold
Minimum difference between any two stimuli that a person can detect 50% of the time.
Just Noticeable Difference (JND)
Experience of the difference threshold.
Weber’s Law
Difference thresholds increase in proportion to the size of the stimulus.
Subliminal Stimulation
Receiving messages below one’s absolute threshold for conscious awareness.
Transduction
Transformation of stimulus energy to the electrochemical energy of neural impulses.
Perception
The process of selecting, organizing, and interpreting sensations, enabling you to recognize meaningful objects and events.
Cornea
Transparent, curved layer in the front of the eye that bends incoming light rays.
Iris
Colored muscle surrounding the pupil that relegates the size of the pupil opening.
Pupil
Small adjustable opening in the iris that is smaller in bright light and larger in darkness.
Lens
Structure behind the pupil that changes shape, becoming more spherical or flatter to focus incoming Rays into an image on the light-sensitive retina.
Accommodation
Process of changing the curvature of the lens to focus light rays on the retina.
Retina
Light sensitive surface in the back of the eye containing rods and cones that transducer light energy. Also has layers of bipolar cells and ganglion cells that transmit visual info to the brain.
Fovea
Small area of the retina in the most direct line of sight where cones are most concentrated for highest visual activity in bright light.
Photoreceptors
Modified neurons that convert light energy to electrochemical neural impulses.
Rods
Photoreceptors that detect black, white, and gray and that detect movement. Necessary for peripheral and dim-light vision when cones do not respond. Distributed throughout the retina but not in the fovea.
Cones
Photoreceptors that detect color and fine detail in daylight or in bright light conditions. Most concentrated in the fovea of the retina; none in the periphery.
Bipolar Cells
Second layer of neurons in the retina that transmit impulses from rods and cones to ganglion cells.
Ganglion Cells
Third layer of neurons in the retina, whose axons converge to form the optic nerve.
Blind spot
Region of the retina where the optic nerve leaves the eye so there are no receptor cells; creates an area with no vision.
Optic Nerve
Nerve formed by ganglion cell axons; carries the neural impulses from the eye to the thalamus.
Acuity
Ability to detect fine details; can be affected by small distortions in the shape of the eye.
Dark adaptation
Increased visual sensitivity that gradually develops when it’s dark.
Feature Detectors
Individual neurons in the primary visual cotes/occipital lobes that respond to specific features of a visual stimulus.
Parallel Processing
Simultaneously analyzing different elements of sensory info such as color, brightness, shape, etc.
Trichromatic Theory
Proposed mechanism for color vision with cones that are differentially sensitive to different wave lengths of light.
Opponent Process Theory
Proposed mechanism for color vision with opposing retinal processes for red-green, yellow-blue, white-black. Some are stimulated and some are inhibited.
Attention
The set process from which you choose among the various stimuli bombarding your senses at any instant, allowing some to be further processed by your senses and brain.
Audition
The sense of hearing. Loudness is determined by the amplitude/height of the sound wave.
Frequency
The # of complete wavelengths that pass a point in a given amount of time. Wavelength is inversely proportional to the frequency.
Pitch
The highness/lowness of a sound. Shorter = higher frequency/higher pitch. Longer = lower frequency/lower pitch.
Timbre
The quality of a sound determined by the purity of a waveform.
Sound Localization
The process by which you determine the location of a sound.
Cochlea
Snail-shaped fluid filled tube in the inner ear with hair cells on the basilar membrane that transduce mechanical energy of vibrating molecules to the electrochemical energy of neural impulses.
Auditory Nerve
Axons of neurons in the cochlea converge transmitting sound messages through the medulla, pons, and thalamus to re auditory cortex of the temporal lobes.
Conduction Deafness
Loss of hearing that results when the eardrum is punctured or any of the ossicles lose their ability to vibrate. A hearing aid may restore hearing.
Nerve (Sensorineural) Deafness
Loss of hearing that results from damage to the cochlea, hair cells, or auditory neurons. Cochlear implants may restore some hearing.
Place theory
The position on the basilar membrane at which waves reach their peak depends on the frequency of a tone. Accounts for high pitch sounds.
Frequency Theory
The rate of neural impulses traveling up the auditory nerve matches the frequency of a tone, enabling you to sense it’s pitch. Explains low pitch sounds.
Somatosensation
The skin sensations: touch/pressure, warmth, cold, and pain.
Gate-Control Theory
Pain is experienced only if the pain messages can pass through a gate in the spinal cord on their route to the brain.
Kinesthesis
Body sense that provides info about the position and movements of individual parts of the body with receptors in muscles, tendons, and joints.
Vestibular Sense
Body sense of equilibrium with hairlike receptors in semicircular canals and vestibular sac in the inner ear.
Gustation
The chemical sense of taste with receptor cells in taste buds in fungiform papillae on the tongue and roof of the mouth and throat. Molecules must be dissolved to be sensed.
Olfaction
The chemical sense of smell with receptors in a mucous membrane on the roof of the nasal cavity. Molecules must reach the membrane and dissolve to be sensed.
Top down processing
Info processing guided by our preexsisting knowledge or expectations to construct perceptions; is concept driven.
Bottom up processing
Info processing that begins with sensory receptors and works up to the brain’s integration of sensory info to construct perceptions; is data-driven.
Perceptual Constancy
Perceiving an object as unchanging even when the immediate sensation of the object changes.
Visual Capture
Vision is the dominant sense
Depth Perception
The ability to to judge the distance of objects.
Monocular clues
Clues about distance based on the image of one eye.
Binocular cues
Clues about distance requiring two eyes.
Optical/Visual Illusions
Discrepancies between the appearance of a visual stimulus and its physical reality.
Schemas
Concepts or frameworks that organize and interpret info.
ESP (extrasensory perception)
The controversial claim that perception can occur apart from sensory input.
Parapsychology
The study of paranormal events that investigates claims of ESP, including telepathy, clairvoyance, precognition, and telekinesis or psychokinesis.
Sensation
The process by which you detect physical energy from your environment and encode it as neural signals.
