module 1.6a-1.6b

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Sensory receptors

Sensory nerve ending that respond to stimuli

Perception

The process by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful

Bottom-up processing

Information processing that begins with the sneory receptors and works up to a the brain’s integration of sensory information

Top-down processing

Information processing guided by higher level mental processing, as we construct perceptions drawing on our experience and expectations

Transduction

Conversion of one form of energy into another. In sensation the transforming of physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret

Psychophysics

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Absolute threshold

The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time

Signal detection theory

theory predicting how and when we detect the presence of a faint stimulus amid background stimulation; assumes there is no single absolute threshold and that detection depends partly on a persons experience, expectations, motivation and alertness

Subliminal

Below ones absolute threshold for conscious awareness

Difference threshold

The minimum difference between two stimuli required for detection 50 percent of the time.

Webbers law

The principle that be perceived as different ,two stimuli must differ by a constant minimum percentage.

Sensory adaption

Diminished sensitivity as a consequence of constant stimulation

Wave length

The distance from the peak of one light wave or sound to the peak of the next. Electromagnetic wavelength vary from the short gamma waves to the long pulses of radio transmission

Hue

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

Intensity

The amber of energy in a light wave or sound wave which influences what we perceive as brightness or loudness. Intensity is determined by the waves amplitude

Cornea

The eyes clear protective outer layer,covering the pupil and iris

Pupil

Adjustable opening in the center of the eye through which light enters

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

Lens

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

Retina

The light sensitive back inner surface of the eye, contains the receptors rods and cones plus layers of neurons that begin processing of visual information

Accommodation.

the process by clench the eyes lens changes shape to focus images of near or far objects on the retina

Rods

Retinal receptors that detect black white and gray and are sensitive to movement. Rods are necessary for peripheral and twilight vision, when cones don’t respond

Cones

Retinal receptors are concentrated near the center of the retina and what function in daylight or in well-lit conditions.

Optic nerve

The nerve that carries neural impulses from the eye to the brain

Blind spot

The points at which the optic nerve leaves the eye creating a blind spot because no receptor cells are located there

fovea

Central focal point in the retina, around which the eyes cones cluster

Young Helmholtz trichromatic theory

The theory that the retina contains three different types of color receptors one most sensitive to red one to green one to blue which when stimulated in combination can produce the perception of any color

Opponent process theory

The theory that opposing retinal processes enable color vision.(red, green , blue yellow white and black)

Feature detectors

Nerve cells in the brains visual cortex that respond to specific feature of the stimulus such as shape angle or movement

Parallel processing

Processing multiple aspects of a stimulus or problem simultaneously