Ap Psych Ch6 Outline

AP Psychology Outline: Chapter 6 Sensation and Perception
I. Sensing the World – Basic Principles * Bottom-up processing suggests that we attend to or perceive elements by starting with the smaller, more fine details of that element and then building upward until we have a solid representation of it in our minds. * Top-Down Processing states that we form perceptions (or focus our attention) by starting with the larger concept or idea (it can even be the concept or idea of an object) and then working our way down to the finer details of that concept or idea.
A. Thresholds * An Absolute Threshold is the lowest amount of stimulus needed to notice it 50% of the time. * For example, you turn down the radio to a point where you only hear the faint sound half the time. Then that loudness (decibel) is your absolute threshold for sound. * Signal detection theory predicts when we will detect weak signals (measured as our ratio of “hits to “false alarm”). * It seeks to understand why people respond differently to the same stimuli, and why the same person’s reactions vary as circumstances change. * In the studies of Warm & Dember, 1986, that people’s ability to catch a faint signal diminishes after about 30mins. But this diminishing response depends on the task, on the time of day, and even on whether the participants periodically exercise. * Subliminal stimulation offer recordings that supposedly speak directly to our brains to help us. * 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. * In 1992, Greenwald conducted 16 double-blind experiments evaluating subliminal self-help tapes. His results were uniform: Not one had any therapeutic effect. * Difference threshold, a.k.a. noticeable difference/jnd, is the lowest difference you can detect between 2 stimuli 50% of the time. * For example, if you add 1ounce to a 10-ounce weight, you will detect the difference; ass 1ounce to a 100ounce weight and you probably will not. * Weber’s Law states that two stimuli must differ in percentages or ratios, not amount, for a person to detect it (jnd).

B. Sensory Adaption * Lowered sensitivity due to constant exposure from a stimulus. For example, when you go into someone’s house you notice an odor…but this only lasts for a little while because sensory adaptation allows you to focus your attention on changing environment; it is irritating to be constantly reminded that your foot is in contact with the floor.
II. Vision
A. The stimulus input: Light Energy * Transduction is the conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret. * Light is composed of electromagnetic waves with Wavelengths (distance from one peak to another peak on a wave) and Amplitudes (height of the wave) * Wavelength is the distance from the peak of one light or sound wave to the peak of the next. * The wavelength determines its hue - The dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
B. Visual formation processing * The feature detector cells found in the cortex derive their name from their ability to respond to a scene’s specific features – to particular edges, lines angles, and movements. * Our brain engages to parallel processing which is doing multiple things at once; the brains natural mode of information processing for many functions, including vision. * Jennifer Boyer and her colleagues showed in 2005 the studies of people using magnetic impulse to shut down the brain’s primary visual cortex area. Temporarily disabled people showed a horizontal or vertical line, or a red or green dot. Without seeing anything, resulted 75% guessing the line orientation and 81% right in guessing the dot color.
C. Color Vision * Color processing is described in 2 stages: * Young-Helmholtz trichromatic (three color) theory is the theory that the retina contains three different color receptors-one most sensitive to red, one to green, one to blue-which when stimulated in combination can produce the perception of any color. * For example, there are no receptors especially sensitive to yellow. Yet when both red-sensitive and green-sensitive cones are stimulated, we see yellow. * Opponent-Process theory – Color is then processed by their opponent colors (red-green, blue-yellow, black-white). Some cells are excited by blue and inhibited by yellow, vice versa. Thus, you cannot see a bluish-yellow. * The after image effect tires our neural response to whatever color by staring at it. When we then stare at white, we could see their opponent colors. * Color constancy refers to the importance of surrounding background effects on perceived color. Color constancy states that colors don’t look different even in different illumination (i.e. sunlight or dark room).Green leaves will still be green whether on a clear or cloudy day.

III. Hearing
A. The Stimulus Input: Sound Waves * Sound waves is the resulting stimulus energy – jostling molecules of air, each bumping into the next, like a shove transmitted through a concert hall’s crowded exit tunnel. * Frequency is the number of complete wavelengths that pass a point in a given time. * Frequency determines the pitch – a tone's experienced highness or lowness; depends on frequency * Long waves have low frequency – low pitch. Short waves have high frequency – high pitch.
B. Perceiving pitch * Place theory says that we hear different pitches because specific “places” in the cochlea are stimulated. Thus, the brain determines a sound’s pitch by recognizing the specific place that is generating in neural signal. * Frequency theory says the brain reads pitch by monitoring the frequency of neural impulses travelling up the auditory nerve.
C. Hearing Loss and Deaf Culture * Conduction Deafness – loss of hearing due to damage of eardrum, and/or the tiny bones in middle ear. (Could be fixed by hearing aid) * Nerve Deafness – loss of hearing due to damage to cochlea, basilar membrane, and/or hair cells in the inner ear. (Could be fixed by a bionic ear, implanting a cochlea)

IV. Other Senses
A. Touch * Without the discomfort that makes us occasionally shift position, joints fail from excess strain, and w/o the warnings of pain, the effects of unchecked infections and injuries accumulate. * There are different nociceptors – sensory receptors that detect hurtful temperatures, pressure, or chemicals. * The Gate-Control Theory states that the spinal cord has “gates” that opens/closes to transmit pain impulses. Small fibers open Gate = pain. Large fibers close Gate = no pain.
B. Taste * Sensory interaction is the principle that one sense may influence another, as when the smell of food influences its taste. * If I watch a video with simultaneous captioning, I have no trouble hearing the words I am seeing. If I then turn off the captioning, I suddenly realize I need it.
C. Smell * Smell or Olfaction is also a Chemical Sense that directly transmits information from nose to the temporal lobe. The only sense that doesn’t first relay impulses to the Thalamus. * Odor molecules take many different receptors to detect them:
1. Odorants bind to receptors
2. Olfactory receptor cells are activated and send electric signals
3. The signals are relayed via converged axons
4. The signals are transmitted to higher regions of the brain
D. Body Position and Movement * Vestibular Sense – it motors your head’s (and thus body’s) position and movement; it enables you to sense your body position and to maintain your balance.
V. Perceptual Organization
A. Gestalt * Gestalt is when we see things in a whole; emphasized our tendency to integrate pieces of information into meaningful wholes.
B. Form Perception * Figure-ground: organization of visual field into the figure(s) that stand out from the ground * To bring order and form to these basic sensations, our minds follow certain rules for grouping stimuli together: * Proximity: grouping nearby figures together * Similarity: grouping similar figures * Continuity: Perceiving smooth, continuous patterns rather than discontinuous ones * Connectedness: Because they are uniform and linked, we perceive each set of two dots and the line between them as a single unit
C. Depth Perception * Visual cliff: laboratory device for testing depth perception in infants/animals * Gibson and Walk devised a miniature cliff with a glass-covered drop-off to determine whether crawling infants and newborn animals can perceive depth. Even when coaxed, infants are reluctant to venture onto the glass over the cliff. * Binocular cues are depth cues, such as retinal disparity, that depend on the use of two eyes; with one eye, the task becomes noticeably more difficult in judging the distance of nearby objects. * Monocular cues are 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
D. Perceptual Constancy * Perceptual constancy: perception that objects are not changing even under different lighting; allowing identification regardless of angle of view * a door is a door even at 45 degree (shape constancy) angle or 20 feet away(size constancy)
E. Perceptual Adaption * In vision, the ability to adjust to an artificially displaced or even inverted visual field. * For example, given a new pair of glasses, we may feel slightly disoriented, even dizzy. Within a day or two, we adjust. But imagine a far more dramatic new pair of glasses – one that shifts the apparent location of objects 40degrees to the left. All your vision will veer to the left. * Perceptual set is a mental predisposition to perceive one thing and not another. * People perceive an adult-child pair as looking more alike when told they are parent and child. * In 1972, a British newspaper published an unretouched photograph of a “monster” in Scotland’s Loch Ness. If this information creates in you the same perceptual set it did in most of the paper’s readers, you, too, will see the monster in the photo. * Context effect is a given stimulus which may trigger radically different perceptions, partly because of our differing set, but also because of the immediate context. * Imagine hearing a noise interrupted by the words “eel is on the orange,” you would perceive the word as “peel”

IV. Extrasensory Perception (ESP) * The controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition * Telepathy: also interpreted as mind-to-mind communication – one person sending thoughts to another or perceiving another’s thoughts. * Clairvoyance: or perceiving remote events, such as sensing that a friend’s house is on fire * Precognition: or perceiving the future events, such as a political leader’s death or a sporting event’s outcome. * Vague predictions can later be interpreted to match events; Nostradamus claimed his prophecies could not be interpreted till after the event; After many experiments, never had a reproducible ESP phenomenon or individual who can convincingly demonstrate psychic ability