Chapter 3 Psychology Vocabulary

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Sensation
Process through which the senses pick up visual, auditory, and other sensory stimuli and transmit them to the brain.
Perception
Process by which sensory information is actively organized and interpreted by the brain.
Absolute Threshold
Minimum amount of sensory stimulation that can be detected 50% of the time.
Difference Threshold
Measure of the smallest increase or decrease in a physical stimulus that is required to produce a difference in sensation that is noticeable 50% of the times.
Just Noticeable Difference (JND)
Smallest change in sensation that a person is able to detect 50% of the time.
Weber's Law
Law stating that the just noticeable difference (JND) for all the senses depends on a proportion or percentage of change in a stimulus rather than on a fixed amount of change.
Sensory Receptors
Highly specialized cells in the sense organs that detect and respond to one type of sensory stimuli-light,sound,or order, for example-and transduce (convert) the stimuli into neural impulses.
Transduction
Process through which sensory receptors convert the sensory stimulation into neural impulses.
Sensory Adaptation
Process in which sensory receptors grow accustomed to constant, unchanging levels of stimuli over time.
Visible Spectrum
Narrow band of electromagnetic waves visible to the human eye
Cornea
Tough, transparent, protective layer that covers the front of the eye and bends light rays inward through the pupil.
Pupil
Small opening in the center of the colored part of the eye.
Iris
Colored part of the eye that dilates and contracts the pupil to regulate the amount of light that enters the eye.
Lens
Transparent disc-shaped structure behind the iris and the pupil that changes shape as it focuses on objects at varying distances.
Accommodation
Flattening and bulging action of the lens as it focuses images of objects on the retina.
Retina
Layer of tissue that is located on the inner surface of the eyeball and contains the sensory receptors for vision.
Rods
Light-sensitive receptor cells in the retina that look like slender cylinders and allow the eye to respond to low levels of light.
Cones
Light-sensitive, rounder receptor cells in the retina that enable humans to see color and fine detail in adequate light but do not function in very dim light.
Fovea
Small area at the center of the retina that provides the clearest and sharpest vision because it has the largest concentration of cones.
Blind Spot
Point in each retina where there are no rods or cones because the cable of ganglion cells is extending through the retinal wall.
Optic Nerve
Nerve that carries visual information from each retina to both sides of the brain.
Primary Visual Cortes
Part of the brain in which visual information is processed.
Feature Detectors
Neurons in the brain that respond only to specific visual patterns.
Hue
Dimension of light that refers to the specific color perceived.
Saturation
Purity of a color, or the degree to which the light waves producing it are of the same wavelength.
Brightness
Intensity of the light energy that is perceived as a color.
Color Blindness
Inability to distinguish certain colors from one another.
Trichromatic Theory
Theory of color vision suggesting that there are three types of cones in the retina that make a maximal chemical response to one of three colors-red, green, or blue.
Opponent-process Theory
Theory of color vision suggesting that three kinds of cells respond by increasing or decreasing their rate of firing when different colors are present.
Afterimage
Visual sensation that remains after a stimulus is withdrawn.
Frequency
Number of cycles completed by a sound wave, in one second, determining the pitch of the sound; measured in the unit called the hertz.
Amplitude
Measure of the loudness of a sound; expressed in the unit called the decibel.
Decibles (dB)
Units of measurement for the loudness of sounds.
Timbre
Distinctive quality of a sound that distinguishes it from other sounds of the same pitch and loudness.
Audition
Sensation and process of hearing.
Outer Ear
Visible part of the ear, consisting of the pinna and the auditory canal.
Middle Ear
Portion of the ear containing the ossicles, which connect the eardrum to the oval window and amplify sound waves.
Inner Ear
Innermost portion of the ear.
Cochlea
Fluid-filled, snail-shaped, bony chamber in the inner ear that contains the basilar membrane and its hair cells.
Hair Cells
Sensory receptors for hearing that are attached to the basilar membrane in the cochlea.
Place Theory
Theory of hearing that holds that each individual pitch a person hears is determined by the particular location along the basilar membrane of the cochlea that vibrates the most.
Frequency Theory
Theory of hearing that holds that hair cell receptors vibrate the same number of times per second as the sounds that reach them.
Olfaction
Sense of smell
Olfactory Epithelium
Two 1-square-inch patches of tissue, one at the top of each nasal cavity, which together contain about 10 million olfactory neurons, the receptors for smell.
Olfactory Bulbs
Two matchstick-sized structures above the nasal cavities, where smell sensations first register in the brain.
Pheromones
Chemicals excreted by humans and other animals that can have a powerful effect o the behavior of other members of the same species.
Gustation
Sense of taste
Taste Buds
Structures in many of the tongue's papillae that are composed of 60 to 100 receptor cells for taste.
Tactile
Pertaining to the sense of touch.
Gate-control Theory
Theory that an area in the spinal cord acts as a gate that either blocks or transmits pain messages to the brain.
Endorphins
Body's own natural painkillers, which block pain and produce a feeling of well-being.
Kinesthetic Sense
Sense providing information about the position of body parts in relation to each other and the movement of the entire body or its parts.
Vestibular Sense
Sense that detects movement and provides information about the body's orientation in space.
Semicircular Canals
Three fluid-filled tubular canals in the inner ear that sense the rotation of the head.
Gestalt
German word that roughly refers to the whole form, pattern, or configuration that a person perceives.
Perceptual Constancy
Phenomenon that allows us to perceive objects as maintaining stable properties, such as size, shape, and brightness, despite differences in distance, viewing angle, and lighting.
Depth Preception
Ability to perceive the visual world in three dimensions and to judge distances accurately.
Binocular Depth Cues
Depth cues that depend on both eyes working together.
Monocular Depth Cues
Depth cues that can be perceived by one eye alone
Real Motion
Perceptions of motion tied to movements of real objects through space.
Apparent Motion
Perceptions of motion that seem to be psychologically constructed in response to various kinds of stimuli.
Phi Phenomenon
Apparent motion that occurs when several stationary lights in a dark room are flashed on and off in sequence, causing the perception, that a single light is moving from one spot to the next.
Autokinetic Illusion
Apparent motion caused by the movement of the eyes rather than the movement of the objects being viewed.
Illusion
False perception or a misperception of an actual stimulus in the environment.
Attention
Process of sorting through sensations and selecting some for further processing.
Inattentional Blindness
Phenomenon in which we shift our focus from one object to another and, in the process, fail to notice changes in objects to which we are not directly paying attention.
Selective Attention
Screening out irrelevant sensory input in order to attend to a single source of information.
Bottom-up Processing
Information processing in which individual components of a stimulus are combined in the brain and prior knowledge is used to make inferences about these patterns.
Top-down Processing
Information processing in which previous experience and conceptual knowledge are applied in order to recognize the nature of a "whole" and then logically deduce the individual components of that whole.
Perceptual Set
Expectation of what will be perceived, which can affect what actually is perceived.
Mirror Neuron System (MNS)
Network of cells that the brain uses to interpret and produce motor actions and emotion-related behavior.
Subliminal Perception
Capacity to perceive and respond to stimuli that are presented below the threshold of awareness.
Extrasensory Perception (ESP)
Gaining information about objects, events, or another person's thoughts through some means other than the known sensory channels.
Synesthesia
Capacity for experiencing unusual sensations along with ordinary ones.