Unit 3

Sensation

The process of receiving stimulus energies from the external environment and transforming those energies into neural energy.

Perception

The process of organizing and interpreting sensory information to provide meaning.

Bottom-up Processing

Sensory receptors register information about the external environment and send it to the brain.

Top-down Processing

Cognitive processing at the brain’s higher levels that helps interpret sensory information.

Sensory Receptors

Specialized cells that detect stimulus information and transmit it to sensory nerves and the brain.

Frequency

Sensory neurons transmit more frequent currents rather than stronger currents for bright stimuli.

Photoreception

Detection of light, perceived as sight.

Mechanoreception

Detection of pressure, vibration, and movement, perceived as touch, hearing, and equilibrium.

Chemoreception

Detection of chemical stimuli, perceived as smell and taste.

Synaesthesia

One sense induces an experience in another sense.

Occipital lobes

Brain regions responsible for processing visual information.

Temporal lobes

Brain regions responsible for processing auditory information.

Parietal lobes

Brain regions responsible for processing pain, touch, and temperature.

Extrasensory Perception (ESP)

The ability to detect information without concrete sensory input.

Absolute Threshold

The minimum amount of stimulus energy that can be detected.

Noise

Irrelevant and competing stimuli that can interfere with perception.

Difference Threshold

The minimum difference required between two stimuli for detection.

Weber’s Law

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

Subliminal Perception

Detection of information below the level of conscious awareness.

Signal Detection Theory

An approach to perception focusing on decision-making about stimuli amid uncertainty.

Selective Attention

Focusing on a specific aspect of experience while ignoring others.

Perceptual Set

A predisposition to perceive something in a particular way.

Sensory Adaptation

A change in responsiveness of the sensory system based on surrounding stimulation levels.

Inattentional Blindness

The failure to detect unexpected events when attention is focused on a task.

Cocktail Party Effect

The ability to focus on one voice among many in a noisy environment.

Light

A form of electromagnetic energy described in terms of wavelengths.

Sclera

The outer white part of the eye that maintains shape and protects from injury.

Iris

The colored part of the eye.

Pupil

The opening in the center of the eye that regulates light entry.

Cornea

A clear membrane at the front of the eye that bends light.

Lens

A flexible structure that helps with fine details of vision.

Retina

The light-sensitive surface in the eye that converts light to neural impulses.

Rods

Receptor cells in the retina sensitive to light but not color.

Cones

Receptor cells used for color perception.

Fovea

The part of the retina with the best vision.

Optic Nerve

Carries visual information from the retina to the brain.

Blind Spot

The area on the retina without cones or rods.

Visual Cortex

The part of the cerebral cortex involved in vision.

Feature Detectors

Neurons that respond to specific features of a stimulus.

Parallel Processing

Simultaneous distribution of information across different neural pathways.

Binding

Integration of processed information from different neural pathways.

Trichromatic Theory

Theory that color perception is produced by three types of cone receptors.

Opponent-process Theory

Theory that visual cells respond to complementary color pairs.

Figure-ground Relationship

Organizing the perceptual field into stimuli that stand out and those that recede.

Gestalt Psychology

A school of thought on how people organize perceptions into patterns.

Depth Perception

The ability to perceive objects in three dimensions.

Binocular Cues

Depth cues that require both eyes to work together.

Convergence

A binocular cue providing information about depth based on eye muscle movements.

Monocular Cues

Depth cues available from a single eye's image.

Apparent Movement

The perception that a stationary object is moving.

Perceptual Constancy

Recognizing that objects remain constant despite changing sensory input.

Disparity

The difference between images in the two eyes used to determine depth.

Wavelength

Determines the frequency of sound waves.

Pitch

The perceptual experience of sound frequency.

Outer Ear

Comprises the pinna and external auditory canal.

Pinna

The outer part of the ear that collects sounds.

Auditory Canal

The passage through which sound waves travel to the middle ear.

Middle Ear

 Channels and amplifies the sound through the eardrum, hammer, anvil, and stirrup to the inner ear

Eardrum

separates the outer ear from the middle ear and vibrates in response to sound

Oval Window

Opening to the inner ear

Inner Ear

The oval window, cochlea, and basilar membrane which converts sound waves into neural impulses and sends them to the brain.

Place Theory

Each frequency produces vibrations at a particular place on the basilar membrane

Frequency Theory

Theory on how the inner ear registers the frequency of sound, stating that perception of a sounds frequency depends on how often the auditory nerve fires

Volley Principle

Cluster of nerve cells can fire neural impulses in rapid succession, producing a volley of impulses

Auditory Nerve

The nerve structure that receives information about sound from hair cells in the inner ear and carries these impulses to the brain's auditory areas

Touch

We use touch to detect mechanical energy, or pressure against the skin

Thermoreceptors

 Sensory nerve endings under the skin that respond to changes in temperatures at or near the skin and provide input to keep the body's temperature 98.6*

Pain

The sensation that warns us of damage to the body

Papillae

 Rounded bumps above the tongues surface that contain the taste buds, the receptors for taste

Olfactory Epithelium

lines the roof of the nasal cavity and contains a sheet of receptor cells for smell

Kinesthetic Senses

Provide information about movement, posture, and orientation

Vestibular Sense

 Provides information about balance and movement

Semicircular Canals

Three fluid-filled circular tubes in the inner ear containing the sensory receptors that detect head motion caused when an individual tilts or moves the head and or body