Unit 4
Module 16
Module 17
Module 18
Module 20
Module 19
Module 21
Touch
--Essential to development
--"Sense of touch"; mix of distinct senses
--Brain is most sensitive to unexpected stimulation
Sensation: the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
Perception: the process of organizing and interpreting sensory information
Bottom-up Processing: analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
Top-down Processing: information process guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations
Selective Attention: the focusing of conscious awareness on a particular stimulus
Cocktail Party Effect: ability to attend to one voice among many (while being able to detect your name in an unattended voice
Inattentional Blindness: failing to see visible objects when our attention is directed elsewhere
Change Blindness: failing to notice change in the environment
Pop-out Stimuli: stimuli that draws our eyes, and demands our attention (we don't choose to attend to these stimuli
Transduction: conversion of one form of energy into another. In sensation, the transformation of stimulus energies into neural impulses that our brain can interpret
Psychophysics: the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
Gustav Fechner: studied awareness of faint stimuli and psychophysics
Absolute Threshold: the minimum stimulation needed to detect a stimulus 50% of the time
Signal Detection Theory: predicts how and when we detect the presence of a faint stimulus amid background stimulation. Assumes that there is no single absolute threshold, and that detection partially depends on a person's experience, expectations, motivation, and alerness
Subliminal: below one's absolute threshold for conscious awareness
Priming: the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response
Masking Stimulus: interrupts the brain's processing before conscious perception
Difference Threshold: the minimum difference between two stimuli required for detection 50% of the time (just noticeable difference)
Weber's Law: the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (not a specific amount) Ernst Weber
Sensory Adaptation: diminished sensitivity as a consequence of constant stimulation
Perceptual Set: a mental predisposition to perceive one thing and not another, which can influence what we hear, taste, feel, and see
Richard Warren: discovered the brain can work backwards in time to allow a later stimulus to determine how we perceive an earlier one
Parapsychology: the study of paranormal phenomena, including ESP and psychokinesis
Extrasensory Perception (ESP): claim that perception can occur apart from sensory input
Clairvoyance: perceiving remote events (i.e. a house fire in another state)
Precognition: perceiving future events (i.e. an unexpected death next month)
Psychokinesis: ability to manipulate physical matter with the mind
Telepathy: mind-to-mind communication
Visual Organization
Gestalt: an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes
Figure-ground: the organization of the visual field into object (the figures) that stand out from their surroundings (the ground)
Grouping: the perceptual tendency to organize stimuli into coherent groups
Depth Perception
Depth perception: the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance
Visual cliff: a laboratory device for testing depth perception in infants and young animals
Binocular cues: depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal disparity: a binocular cue for perceiving depth: By comparing images from the retinas in the two eyes, the brain computes distance - the greater the disparity (difference) between the two images, the closer the object
Monocular cues: depth cues, such as interposition and linear perspective, available to either eye alone
Phi phenomenon: an illusion of movement created when two or more adjacent lights blink on and off in quick succession
Perceptual Constancy
Perceptual constancy: perceiving objects as unchanging (having consistent shapes, size, brightness, and color) even as illumination and retinal images change
Color constancy: perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Experience and Visual Perception
Perceptual adaptation: in vision, the ability to adjust to an artificially displaced or even inverted visual field
Hearing
Audition: the sense or act of hearing
Frequency: the number of complete wavelengths that pass a point in a given time
Pitch: a tone's experienced highness or lowness; depends on frequency
Middle ear: the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window
Cochlea: a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses
Inner ear: the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
Sensorineural hearing loss: hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
Conduction hearing loss: hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
Cochlear implant: a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
Perceiving Pitch
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
Pain
Biological Influences
--Body's way of telling you something has gone wrong and ordering you to change your behavior
--Chronic pain: alarm that won't shut off
--Sensitivity: combo of genes, physiology, experience, attention, and culture
--Nociceptors: sensory receptors that detect hurtful sensations
--Gate-Control Theory: spinal cord acts as neurological gate; treat chronic pain with electrical stimulation
--Endorphins: natural painkillers
--Phantom limb sensation: brain misinterprets spontaneous CNS activity in absence of normal sensory input
--Other senses: loss of hearing (tinnitus); loss of vision (phantom sights); nerve damage (taste/smell phantoms)
Psychological Influnces
--Distraction: lessens pain
--Memories of pain are edited (focus on peak moment and pain at the end); overlook a pain's duration
Social-Cultural Influences
--Presence of others: perceive more pain when others are experiencing pain also
--Empathy for other's pain: brain may mirror the pain of the other
--Cultural expectations: traditions and social situation
Taste
Smell (olfaction)
Five Basic Sensations
----Taste: indicator for...
--Sweet: energy source
--Salty: sodium is essential
--Sour: potential toxic acid
--Bitter: potential poison
--Umami: protein and tissue repair
Taste is...
--an evolutionary need
--a chemical process
--receptor reproduction
--gives expectations
Body Position and Movement
Sensory Interaction
--We smell something when molecules of a substance carried in the air reaches a tiny cluster of 20 million receptor cells at the top of each nasal cavity
--Sense of smell is less acute than hearing or seeing
--Combination of olfactory receptors allow one to detect 10,000 odors (no distinct receptor for each)
--Attractiveness of smells depends on associations
--Recall of long-forgotten smells = relation to limbic system (memory and emotion)
--Kinesthesia: sense of position and movement of body parts
--Vestibular sense: monitors head's position and movement (sense of balance)
--Brain blends inputs from the different senses (one sense may influence another)
--Smell + texture + taste = flavor
--McGurk Effect: when we see a speaker say one syllable while we hear another, we may perceive a third that blends both inputs
Light Energy
Wavelength: distance from peak of one light/sound wave to the next
Hue: dimension of color, determined by wavelength
Intensity: amount of energy in light/sound wave, determined by amplitude (perceived as brightness or loudness)
The Eye
Pupil: adjustable opening in center of eye that light travels through
Iris: ring of muscle tissue around eye that controls size of pupil opening (colored part of eye)
Lens: transparent structure behind pupil; changes shape to project images on retina
Retina: light-sensitive inner surface of eye where processing of visual information begins
Accommodation: process by which lens changes shape to focus near/far objects on retina
Cones: retinal receptor cells that are concentrated near center of retina that function in daylight or well-lit conditions; detect fine detail and give rise to color sensations
Rods: retinal receptors that detect black,white, and gray; necessary for peripheral and twilight vision, when cones don't respond
Optic Nerve: nerve that carries neural impulses from eye to brain
Fovea: central focal point in retina, around which eye's cones cluster
Seeing
Feature Detectors: nerve cells in brain that respond to specific features of stimulus, such as shape, angle, or movement
Parallel Processing: processing of many aspects of a problem simultaneously
Young-Helmholtz trichromatic (three-color) theory: theory that retina contains three different color receptors (red, green, blue) which, when stimulated in combination, can produce perception of any color
Opponent-process theory: theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision