Sensation and Perception

A comprehensive vocabulary review of sensation and perception concepts based on the lecture notes.

Absolute threshold

The minimum level of stimulation needed to detect a stimulus 50% of the time

Transduction

The process of converting sensory stimuli into neural impulses the brain can interpret

Just noticeable difference (JND)

The smallest change in stimulus that can be detected 50% of the time

Weber’s law

The principle that the JND is a constant proportion of the original stimulus intensity

Synesthesia

A condition where stimulation of one sense leads to automatic experience in another (seeing sounds)

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors

Blind spot

The area of the retina where the optic nerve leaves the eye; no photoreceptors are present

Visual (optic) nerve

The bundle of axons that carries neural signals from the retina to the brain

Photoreceptors

Specialized cells (rods and cones) in the retina that convert light into neural signals

Rods

Photoreceptors sensitive to dim light and movement but not color; located mainly in the peripheral retina

Lens

The transparent structure behind the pupil that focuses light on the retina by changing shape

Accomodation

The process by which the lens changes shape to focus on objects at different distances

Nearsightedness (myopia)

A condition where nearby objects are seen clearly, but distant ones are blurry because light focuses in front of the retina

Farsightedness (hyperopia)

A condition where distant objects are seen clearly, but nearby ones are blurry because light focuses behind the retina

Trichromatic theory

Theory that color vision results from 3 types of cones sensitive to red, green, and blue wavelengths

Opponent-process theory

Theory that vision is based on pairs of opposing colors (red-green)

Fovea

Central part of the retina where cones are concentrated; responsible for sharp central vision

Cones

Photoreceptors responsible for color vision and detail; work best in bright light

Ganglion cells

Neurons in the retina whose axons form the optic nerve and transmit visual info to the brain

Dichromatism

A type of color blindness where one of the three cone systems is missing or malfunctioning

Monochromatism

A condition in which color vision is absent or extremely limited

Subliminal

Below the level of conscious awareness

Sensory adaptation

Reduced sensitivity to a constant, unchanging stimulus over time

Prosopagnosia

The inability or difficulty recognizing faces, also called face blindness

Blindsight

The ability to respond to visual information without consciously seeing it

Place theory

The theory that pitch is determined by where the basilar membrane vibrates in the cochlea

Volley theory

The theory that groups of auditory neurons take turns firing to encode sound frequencies too fast for one neuron to match alone

Frequency theory

The theory that pitch is determined by the rate of neural impulses matching the sound frequency

Conduction deafness

Hearing loss caused by problems transmitting sound through the outer or middle ear

Sensorineural deafness

Hearing loss caused by damage to the cochlea's hair cells or the auditory nerve

Pheromones

Chemical signals released by organisms that can affect the behavior or physiology of others of the same species

Gustation

The sense of taste

Olfaction

The sense of smell

Gate control theory

The theory that the spinal cord can regulate pain signals traveling to the brain

Phantom limb syndrome

Feeling sensations, including pain, in a limb that has been amputated

Vestibular sense

The sense of balance and head movement

Semicircular canals

Fluid-filled structures in the inner ear that help detect head rotation and maintain balance

Kinesthesis

The sense of the position and movement of body parts

Top-down processing

Interpreting information using prior knowledge, expectations, and experiences

Bottom-up processing

Building perception from individual sensory details

Perceptual sets

Mental predispositions to perceive something in a particular way based on expectations or experiences

Gestalt psychology

An approach emphasizing that we perceive whole patterns rather than just individual parts

Figure/ground

The tendency to distinguish a main object (figure) from its background (ground)

Selective attention

Focusing awareness on one stimulus while ignoring others

Cocktail party effect

The ability to focus on one conversation while filtering out others, yet notice personally relevant information, such as your name

Inattentional blindness

Failing to notice a visible object because attention is focused elsewhere

Change blindness

Failing to notice changes in a visual scene

Binocular depth cues

Depth cues that require both eyes to perceive distance

Monocular depth cues

Depth cues that can be perceived using just one eye

Retinal disparity

The difference between the images received by each eye, which helps the brain judge depth

Interposition

A monocular depth cue in which an object blocking another object is perceived as closer

Linear perspective

A monocular depth cue in which parallel lines appear to converge as they get farther away