Sensation and Perception

Sensation

Process of receiving and representing stimulus energies from environment

Sensory receptors

Nerve endings that respond to stimuli

Perception

Process of organizing and interpreting sensory information

Bottom-up processing

Analysis starting with sensory receptors and integrating sensory information

Top-down processing

Information processing guided by higher-level mental processes

Selective attention

Focusing conscious awareness on a particular stimulus

Inattentional blindness

Failing to see visible objects when attention is directed elsewhere

Change blindness

Failing to notice changes in the environment

Transduction

Conversion of stimulus energies into neural impulses

Psychophysics

Study of relationships between physical characteristics of stimuli and psychological experience

Absolute thresholds

Minimum stimulus needed to detect a particular stimulus 50% of the time

Signal detection theory

Theory predicting how and when we detect faint stimuli amid background stimulation

Subliminal

Below threshold for conscious awareness

Difference thresholds

Minimum difference between two stimuli required for detection 50% of the time

aka just noticeable difference (JND)

Priming

Activation of certain associations, predisposing perception, memory, or response

Weber's Law

Principle that two stimuli must differ by a constant minimum percentage to be perceived as different

Sensory adaptation

Diminished sensitivity due to constant stimulation

Perceptual set**

Mental predisposition to perceive one thing and not another

Extrasensory perception (ESP)**

Controversial claim that perception can occur apart from sensory input

Parapsychology**

Study of paranormal phenomena, including ESP and psychokinesis

Wavelength

Distance from peak of one light or sound wave to the peak of the next

Hue

Dimension of color determined by wavelength of light

Intensity

Amount of energy in a light or sound wave

Cornea

Eye's clear, protective outer layer

Pupil

Adjustable opening in the center of the eye

Iris

Ring of muscle tissue that controls the size of the pupil opening

Lens

Transparent structure behind the pupil that changes shape to focus images on the retina

Retina

Light-sensitive inner surface of the eye

Accommodation

Process by which the eye's lens changes shape to focus on near or far objects

Rods

Retinal receptors that detect black, white, and gray

Cones

Retinal receptors that detect fine detail and color

Fovea

Central focal point in the retina

Optic nerve

Nerve that carries neural impulses from the eye to the brain

Blind spot

Point where optic nerve leaves the eye, creating a blind spot

Young-Helmholtz trichromatic theory

Theory that the retina contains three different types of color receptors

Opponent-process theory

Theory that opposing retinal processes enable color vision

Feature detectors

Nerve cells in the brain's visual cortex that respond to specific features of the stimulus

Parallel processing

Processing many aspects of a problem simultaneously

Gestalt

An organized whole

Figure-ground

Organization of the visual field into objects and their surroundings

Grouping

Perceptual tendency to organize stimuli into coherent groups

Depth perception

Ability to see objects in three dimensions

Visual cliff

Laboratory device for testing depth perception

Binocular cues

Depth cues that depend on the use of two eyes

Retinal disparity

Binocular cue for perceiving depth

Monocular cues

Depth cues available to either eye alone

Phi phenomenon

Illusion of movement created by blinking lights

Perceptual constancy

Perceiving objects as unchanging despite changing retinal images

Color constancy

Perceiving familiar objects as having consistent color

Perceptual adaptation

Ability to adjust to changed sensory input

Audition**

Sense of hearing

Frequency**

Number of complete wavelengths that pass a point in a given time

Pitch**

Experienced highness or lowness of a tone

Middle ear**

Chamber between the eardrum and cochlea

Cochlea**

Coiled, fluid-filled tube in the inner ear

Inner ear**

Innermost part of the ear

Sensorineural hearing loss**

Hearing loss due to damage to the cochlea's receptor cells or auditory nerves

Conduction hearing loss**

Hearing loss due to damage to the mechanical system conducting sound waves

Cochlear implant**

Device for converting sounds into electrical signals and stimulating the auditory nerve

Place theory**

Theory linking pitch with the place where the cochlea's membrane is stimulated

Frequency theory**

Theory linking pitch with the rate of nerve impulses traveling up the auditory nerve

Gate-control theory

Theory that the spinal cord contains a neurological 'gate' that blocks pain signals

Olfaction

Sense of smell

Kinesthesia

Sense of movement and position of individual body parts

Vestibular sense

Sense of body movement and position for balance

Sensory interaction

Principle that one sense may influence another

Embodied cognition

Influence of bodily sensations on cognitive preferences and judgments

anosmia

the complete loss of smell

closure

tendency to overlook completeness to perceive the whole

continuity

items that continue a pattern or direction are grouped as a pattern

proximity

when objects are close to each other, we group them together

dichromacy

a form of color blindness