Psychology Sensation and Perception

Transduction

A process by which sensory receptors produce neural impulses when they receive physical or chemical stimulation.

Sensory adaptation

Diminished sensitivity as a consequence of constant stimulation

Sensory Habituation

our perception of sensations is partially due to how focused we are on them

Cocktail Party Effect

The ability to focus one's listening attention on a single talker among a mixture of conversations and background noises

Sensation

Detection of physical energy by sense organs, which then send information to the brain, Bottom-up processing

Perception

A person's cognitive (mental) interpretation of events.

Cornea

Anatomy of the eye: outermost transparent layer protecting the eye; assists in light refraction

Pupil

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

Lens

A clear piece of curved glass or plastic that bends passing light to focus or spread the light rays

Retina

A multilayered sensory tissue that lines the back of the eye and contains the receptor cells to detect light.

Feature Detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

Optic Nerve

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

Rods

Located in the periphery of the retina, these are sensory receptors for vision that work best in reduced illumination, and only allow perception of achromatic colors, low sensitivity to detail and are not involved in color vision.

Cones

Cone-shaped visual receptor cells; located in retina; works best in bright light; responsible for viewing color; greatest density in the fovea

Fovea

Point of central focus". Spot on the back of the retina that has more cones that anywhere else. Helps us see fine detail

Blind Spot

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

Trichromatic Theory

Firing of red, green and blue cones cause color vision. (Young Helmholtz)

Color Blindness

a total inability to perceive colors

Afterimages

Images that occur when a visual sensation persists for a brief time even after the original stimulus is removed

Opponent-Process Theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

Pitch Theory

different portions of the membrane vibrate according to which pitch is sent through them

Place Theory

In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated

Frequency Theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.

Conduction Deafness

An inability to hear resulting from damage to structures of the middle or inner ear.

Nerve Deafness

Inner-ear deafness resulting from damage to the cochlea, hair cells, or auditory nerve

Gate-Control Theory

The spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain.

Taste (Gustation)

chemical sense, involves four basic sensations: sweet, salty, sour, and bitter

Smell (Olfaction)

most primitive sense. information transmitted directly to limbic system not thalamus and cortex

Vestibular Sense

the sense of body movement and position, including the sense of balance

Kinesthetic Sense

The sense of body position and movement of body parts relative to each other

Absolute Threshold

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

Subliminal Messages

brief auditory or visual messages that are presented below the absolute threshold

Difference Threshold

The minimum amount of difference that can be detected between two stimuli

Webers Law

principle that the just noticeable diffference of a stimulus is a constant proportion despite variations

Signal Detection Theory

A theory predicting how and when we detect the presence of a faint stimulus amid background noise

Top-Down Processing

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

Perceptual Set

A mental predisposition to perceive one thing and not another

Bottom-up Processing

Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

Gestalt Rules

we normally perceive images as groups, not as isolated elements; 4 factors that influence: proximity, similarity, continuity, closure

Proximity

Nearness

Similarity

A law of organization that says that objects that look similar tend to be grouped together when we perceive them.

Continuity

We perceive smooth, continuous patterns rather than discontinuous ones.

Closure

An ending or completion, or something that gives a sense of finality.

Constancy

The tendency to perceive certain objects in the same way regardless of changing angle, distance, or lighting

Size constancy

Perception of an object as the same size regardless of the distance from which it is viewed

Shape Constancy

the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina

Brightness Constancy

the tendency to perceive the apparent brightness of an object as the same even when the light conditions change

Depth Cues

Binocular Cues

binocular Clues

depth cues, such as retinal disparity, that depend on the use of two eyes

Monocular Clues

depth cues, such as interposition and linear perspective, available to either eye alone