Chapter 5 Sensation

The process by which we detect physical energy from the environment and encode it as neural signals. sensation

The process by which the brain organizes and interprets sensory information. perception

Analysis that begins with the sense receptors and works up to the brain’s integration of sensory information. Bottom-up processing

Information processing guided by higher-level mental processes. Top-down processing

The study of relationships between the physical characteristics of stimuli and our psychological experience of them. psychophysics

The minimum stimulation needed to detect a stimulus 50% of the time. absolute threshold

signal detection theory This theory explains precisely how and when we detect the presence of a faint stimulus. Detection depends partly on experience, expectation, motivation, and alertness. signal detection theory

A stimulus that is below the absolute threshold for awareness. subliminal

The activation, often unconscious, of certain associations, thus predisposing one’s perceptions, memory, or response. priming

The minimum difference between two stimuli required for detection 50% of the time. We experience it as a just noticeable difference or jnd. difference threshold

Whose law states that the just noticeable difference between two stimuli is a constant minimum proportion of the stimulus? Weber’s Law

The decreased sensitivity that occurs with continued exposure to an unchanging stimulus. sensory adaptation

In the study of sensation, the process by which receptor cells in the eye, ear, skin, and nose convert environmental stimuli into neural impulses. transduction

Refers to the distance from the peak of one light (or sound) wave to the next and gives rise to the perceptual experiences of hue (color) in vision. wavelength

The dimension of color that is determined by the wavelength of light; what we know as the color names: blue, green, and so forth. hue

The _____ of light and sound is determined by the amplitude of the waves and is experienced as brightness and loudness. intensity

The adjustable opening in the eye through which light enters. pupil

A ring of muscle tissue that forms the colored part of the eye that controls the diameter of the pupil. iris

The transparent structure of the eye behind the pupil that changes shape to focus images on the retina. lens

The process by which the lens of the eye changes shape to focus near objects on the retina. accommodation

The light-sensitive, multilayered inner surface of the eye that contains the rods and cones, as well as neurons that form the beginning of the optic nerve. retina

Visual _____ refers to the sharpness of vision. acuity

A condition in which nearby objects are seen clearly but distant objects are blurred because light rays reflecting from them converge in front of the retina. nearsightedness

A condition in which distant objects are seen clearly but nearby objects are blurred because light rays reflecting from them strike the retina before converging. farsightedness

Visual receptors concentrated in the periphery of the retina - have poor sensitivity, detect black and white, and function well in dim light. rods

Visual receptors concentrated in the fovea – have excellent sensitivity, enable color vision, and function best in daylight or bright light. cones

Comprised of the axons of retinal ganglion cells, it carries neural impulses from the eye to the brain. optic nerve

The region of the retina where the optic nerve leaves the eye The region of the retina where the optic nerve leaves the eye. Because there are no rods or cones in this area, there is no vision here. blind spot

The retina’s point of central focus The retina’s point of central focus. It contains only cones; therefore, images focused on it are the clearest. fovea

Located in the visual cortex of the brain, are these nerve cells that selectively respond to specific visual features, such as movement, shape, or angle. Evidently the basis of visual information processing. feature detectors

Information processing in which several aspects of a stimulus, such as light or sound, are processed simultaneously. parallel processing

Young-Helmholtz trichromatic (3-color) theory This theory maintains that the retina contains red-, green-, and blue-sensitive color receptors that in combination can produce the perception of any color. First stage of color processing. Young-Helmholtz trichromatic (3-color) theory

opponent-process theory This theory maintains that color vision depends on pairs of opposing retinal processes (red-green, yellow-blue, and white-black). Second stage of color processing. opponent-process theory

The perception that familiar objects have consistent color despire changes in illumination that shift the wavelengths they reflect. color constancy

Refers to the sense of hearing. audition

The number of complete wavelengths that can pass a point in a given time (directly related to wavelength and determines pitch). frequency

A tone’s experienced highness or lowness; depends of frequency. pitch

The chamber between the eardrum and cochlea containing the three bones (hammer, anvil, and stirrup) that concentrate the eardrum’s vibrations on the cochlea’s oval window. middle ear

The coiled, bony, fluid-filled tube of the inner ear where the transduction of sound waves into neural impulses occurs. cochlea

Contains the semicircular canals and the cochlea, which includes the receptors that transduce sound energy into neural impulses. inner ear

The theory of hearing that states that we hear different pitches because sound waves of varioius frequencies trigger activity at different places on the cochlea’s basilar membrane. place theory

The theory of hearing that presumes that the rate, or frequency, of nerve impulses in the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. frequency theory

conduction hearing loss The hearing loss that results from damage in the mechanics of the outer or middle ear, which impairs the conduction of sound waves to the cochlea. conduction hearing loss

Sensorineural hearing loss Nerve deafness – hearing loss caused by damage to the auditory receptors of the cochlea or to the auditory nerve due to disease, aging, or prolonged exposure to ear-splitting noise. Sensorineural hearing loss

A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea. Cochlear implant

Melzack and Wall’s theory that maintains that a “gate” in the spinal cord determines whether pain signals are permitted to reach the brain. Neural activity in small nerve fibers opens the gate; activity in large fibers or information from the brain closes the gate. gate-control theory

The principle that one sense may influence another. sensory interaction

The sense of the position and movement of the parts of the body. kinesthesis

The sense of body movement, position, and balance. vestibular sense