Psych Sensation + Perception

Sensation

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

Perception

The process of organizing and interpreting sensory information to form a meaningful understanding of the world.

Prosopagnosia

A top‐down processing deficiency where sensory input is normal, but the ability to organize and interpret faces is impaired.

Top-down processing

A process where perceptions are constructed from existing knowledge, experiences, expectations, and context.

Bottom-up processing

An analysis that begins at the sensory receptors, detecting basic features and building up a complete perception.

Absolute threshold

The minimum amount of stimulation needed for a person to detect a stimulus 50% of the time.

Difference threshold/Just Noticeable Difference (JND)

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

Weber’s Law

States that to detect a difference between two stimuli, they must differ by a constant percentage.

Sensory adaptation

A decrease in sensitivity to a constant stimulus over time.

Transduction

The process by which one form of energy is converted into another; in sensory systems, the conversion of physical energy into neural impulses.

Accommodation (in sight)

The process by which the eye's lens changes its optical power to maintain a clear image on the retina.

Amplitude

Refers to the height of sound and light waves; in sound, it means louder sound, and in light, it means higher brightness.

Wavelength

The distance from peak to peak of sound and light waves, determining hue in light and contributing to pitch in sound.

Parallel processing

The brain's ability to process multiple aspects of a stimulus simultaneously.

Opponent-processing theory

Theory explaining color perception controlled by pairs of opposing processes: red vs. green, blue vs. yellow, and black vs. white.

Helmholtz trichromatic theory

Proposes that the retina contains three types of cones, sensitive to red, green, and blue.

Audition

The sense that detects sound waves, involving the reception of sound by the ear and its conversion into neural signals.

Cochlea

A spiral-shaped, fluid-filled structure in the inner ear responsible for transducing sound vibrations into neural impulses.

Place theory

Theory stating different frequencies of sound are detected by different places along the basilar membrane.

Frequency theory

Proposes that the rate of nerve impulses matches the frequency of a sound wave for pitch perception.

Volley Principle

An extension of frequency theory suggesting groups of auditory neurons respond to sound by firing in rapid bursts.

Sensory interaction

The way different senses influence each other, exemplified by the McGurk effect.

Kinesthesis

Also known as proprioception, it is the sense that informs about the position and movement of body parts.

Vestibular sense

The sensory system that provides information about balance and spatial orientation.

Parts of the eye

Cornea, pupil, iris, lens, retina; structures involved in focusing light onto the retina.

Rods

Photoreceptors responsible for vision in low light and detecting shades of gray.

Cones

Photoreceptors responsible for color vision and high visual acuity.

Fovea

The central area of the retina providing sharp vision.

Blind Spot

The point where the optic nerve exits the eye; contains no photoreceptors.

Transduction in the eye

Occurs in the photoreceptor cells (rods and cones) of the retina.

Parts of the ear

Outer ear, eardrum, ossicles, oval window, cochlea; structures that transmit and transduce sound waves.

Transduction in the ear

Occurs in the hair cells on the basilar membrane within the cochlea.

Conductive hearing loss

Hearing loss caused by problems in the outer or middle ear preventing sound from reaching the inner ear.

Sensorineural hearing loss

Hearing loss caused by damage to cochlear hair cells or the auditory nerve.

Chemical senses

Taste and smell, which depend on chemical interactions with receptor cells.

Olfactory receptor neurons

Receptor cells essential for detecting odorants.

Selective attention

The process of focusing conscious awareness on one specific stimulus while filtering out others.

Inattentional Blindness

The failure to notice an unexpected stimulus in the visual field when attention is focused on another task.

Gate control theory

Pain signals can be modulated in the spinal cord by simultaneous non-painful stimuli.

Cocktail party effect

The ability to focus on one conversation in a noisy environment and notice relevant information.

Change blindness

The failure to detect large changes in a visual scene when they occur during a brief disruption.

Dominant sense

Vision tends to dominate over other senses when competing.

Proximity (Gestalt principle)

Elements that are close together are perceived as part of the same group.

Similarity (Gestalt principle)

Objects similar in appearance are grouped together perceptually.

Continuity (Gestalt principle)

Elements arranged in a line or smooth curve are perceived as more related.

Connectedness (Gestalt principle)

Elements that are visually connected are perceived as belonging together.

Closure (Gestalt principle)

The mind fills in missing information to create a complete object.

Retinal disparity

The slight difference in images received by each eye, used by the brain to gauge depth.

Binocular cues

Depth cues that require both eyes, including retinal disparity and convergence.

Monocular cues

Depth cues that can be perceived with one eye alone.

Depth perception

The ability to perceive depth, tested in infants using the visual cliff experiment.

Relative Size, Clarity, and Height

Monocular cues for depth perception based on size, clarity, and height in the visual field.

Linear perspective

A monocular cue where parallel lines converge as they recede into the distance.

Stroboscopic movement

The illusion of continuous motion created by rapidly presented still images.

Phi phenomenon

An optical illusion where sequentially illuminated lights appear as continuous movement.

Size constancy

The perception that an object's size remains constant despite changes in distance.

Interposition

A monocular cue where an object blocking another is perceived as closer.

Color constancy

The tendency to perceive colors as constant under varying illumination.

Context effects

The influence of surrounding stimuli on the perception of a stimulus.