Sensation and Perception: A Comprehensive Guide to How We Experience the World
What is consciousness? Our awareness of ourselves and our environment.
What is dual processing? Which track (conscious or unconscious) processes information in parallel? Which track processes information serially? Dual processing is the principle that information is often simultaneously processed on separate conscious & unconscious tracks. Unconscious information processing occurs simultaneously on multiple parallel tracks. Track information serially serial conscious processing
What is selective attention? Inattentional blindness? Change blindness? Selective attention the focusing of conscious awareness on a particular stimulus Inattentional blindness is failing to see visible objects when our attention is directed elsewhere Change blindness failing to notice changes in the environment
What are circadian rhythms? What is sleep? How do we study sleep? Circadian rhythms are the biological clock, regular bodily rhythms, ex. temperature, that occur on a 24-hour cycle. We study sleep by measuring brain-wave activity, eye movements, and muscle tension by electrodes that pick up weak electrical signals from the brain, eye, and facial muscles
(NREM-1, NREM-2, NREM-3, REM what brain waves are present in each stage? What is a hypnagogic sensation and in what stage does it occur? What stage is deep sleep? In what stage do we usually dream? Why is REM sleep called paradoxical sleep? Stage 1 NREM sleep: mixture of alpha & theta brainwaves Stage 2 NREM sleep spindles, K complexes, theta brain waves, & beginnings of delta wave Stage 3 NREM mixture of theta & delta brain waves Stage 4 NREM delta brain waves REM fast active brain waves accompanied by rapid eye movement HYPNAGOGIC IS stage 1 when you feel like you are weightless Stage 3 & 4 deep sleep, sleep REM is paradoxical sleep b/c the muscles are relaxed but other body systems are active
How long does a sleep cycle last? How many do people have per night? Cycle lasts 90 min & repeats 4-6 times over the course of a night. The amount of time you spend in each stage of sleep changes as the night progresses
How does light affect sleep? What hormone induces sleep? What are some of the theories of why we sleep? Light in the morning tweaks the circadian clock by activating light-sensitive retinal proteins. These proteins control the circadian clock by triggering signals to the brain’s suprachiasmatic nucleus, which is part of a grain of rice-sized, 20,000 cell cluster in the hypothalamus. The SCN does its job by causing the brain’s pineal gland to decrease its production of melatonin in the morning or increase it in the evening. MELATONIN HORMONE INDUCES SLEEP. Theories are 1) sleep protects. 2) Sleep helps us recuperate 3) sleep is for making memories 4) sleep also feeds creative thinking 5) sleep may play a role in the growth process.
What is sleep deprivation? What are the consequences of sleep deprivation? Be familiar with the Coren study. Figure 3.16
Sleep deprivation is the slowed performance and impairment of concentration that can be caused by sleep deprivation consequences: Irritability, Cognitive impairment, memory lapses or loss, impaired moral judgment, severe yawning, hallucinations, symptoms similar to ADHD, impaired immune system, Risk of diabetes type 2, Increased heart rate variability, risk of heart disease, decreased reaction time and accuracy, tremors, aches, other growth suppression, risk of obesity, decreased temperature. 3.16 On the Monday after the spring time change, when people lose one hour of sleep, accidents increased as compared with the Monday before. In the fall, traffic accidents normally increase because of greater snow, ice, and darkness, but they diminished after the time change
Sleep disorders: What is insomnia? Sleep apnea? Narcolepsy? What are night terrors? In what stage of sleep does sleepwalking usually occur? Insomnia, persistent inability to fall asleep or stay asleep Sleep apnea repeated awakening after breathing stops, time in bed not restorative sleep Narcolepsy is sleep attacks, even a collapse into REM/paralyzed sleep. Night terrors refer to sudden scared-looking behavior, with rapid heartbeat and breathing. Sleepwalking happens in NREM 3 sleep. RUN GENES
What are dreams? What do we tend to dream about? Can we incorporate external stimuli into a dream (see Dement and Wolpert 1958 study )? Can we learn while sleeping?
Dreams are a sequence of images, emotions, & thoughts passing through a sleeping person’s mind. Dreams are notable for their hallucinatory imagery, discontinuities, and incongruities & for the dreamer’s delusional acceptance of the content and later difficulties remembering it. Common themes are failing in an attempt to do something, being attacked, pursued, or rejected. Dement & Wolpert experiment, researchers sprayed water on sleeping people’s faces, the people were more likely to dream about waterfalls, leaky roofs. NO, WE DO NOT REMEMBER RECORDED INFORMATION PLAYED WHILE SLEEP
What are psychoactive drugs? What is tolerance? Withdrawal? Physical dependence? Psychological dependence? Addiction? Psychoactive drugs a chemical substance that alters perceptions and moods. Tolerance the drug user needs to take larger doses to get the desired effect. This is referred to as Withdrawal is the discomfort and distress that follow discontinuing an addictive drug or behavior. Physical Dependence is a physiologic adaptation of the body to the presence of drug associated with withdrawal ex. nicotine Psychological dependence is pattern of compulsive drug use characterized by a continued craving for the drug and the need to use for effects -ex. nicotine Addiction is defined as a behavioral syndrome characterized by the repeated compulsive seeking
What are depressants? Review the numerous effects alcohol can have including these issues: What stage of sleep does alcohol suppress? Depressants:drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions. Effects of alcohol can slow body functions, reduce neural activity. 1) expectancy effect 2) Reduce self-awareness and self-control 3) Memory Disruption 4) slowed neural processing suppresses REM sleep nerve cell death
What are barbiturates? What are opiates? Barbiturates:drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment.Opiates:opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety.
–What are stimulants? What are amphetamines? What are the physiological effects of nicotine; Figure 3.22? How does cocaine have an effect Figure 3.23? What is methamphetamine? What neurotransmitter does methamphetamine increase? Stimulants:drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, Ecstasy, and methamphetamine) that excite neural activity and speed up body functions.Amphetamines:drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes. Physiological effects of nicotine reaches the brain within 7 seconds, Within minutes the amount in the blood soars. Arouses the brain, increases heart rate, relaxes muscles & trigger release of neurotransmitters that reduce stress, reduces circulation, suppresses appetite for carbohydrates. Cocaine Effect euphoria to crash Methamphetamine:a powerfully addictive drug that stimulates the central nervous system, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels. INCREASES DOPAMINE serotonin, and norepinephrine .
-What is ecstasy? What neurotransmitters does ecstasy impact? What are its long-term risks?
ECSTASY IS a synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition. Blocks reuptake of serotoninECSTASY IMPACT serotoninRISK IS weaker immune system, memory impairment, slowness of thought, sleep disruption, disrupts serotonin production
What are hallucinogens? What is LSD?
Hallucinogens:psychedelic (“mind-manifesting”) drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input.LSD:a powerful hallucinogenic drug; also known as acid(lysergic acid diethylamide).
What is THC? What are some of the effects of marijuana use? THC:the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations.EFFECTS ARE amplifies sensitivity to colors, sounds, tastes, and smells; euphoria, perception, intensifies feelings, stays longer than alcohol
-What is the difference between sensation and perception? What is bottom-up processing? Top-down processing? Sensation – process by which the sense organs gather info about the environment Perception – process by which the brain selects, organizes and interprets sensationBottom-up processing Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information. Top-down processing Using prior experience, knowledge, and expectations to influence perception
-What is transduction? Sensory neurons project to the Somatosensory cortex in the parietal lobe
-What is an absolute threshold? The minimum stimulation needed to detect a particular stimulus 50 percent of the time
-What is signal detection theory?
A theory predicting how and when we detect the presence of a faint stimulus “signa”) amid background stimulation “nois”). Assumes there is no single absolute threshold and detection depends partly on a person’s experience, expectations, motivation, and level of fatigue.
-What does it mean that something is subliminal? Can we detect subliminal stimuli unconsciously? What is a prime? Does subliminal persuasion have a powerful enduring effect on behavior? Below one’s absolute threshold for conscious awareness stimuli cannot detect 50 percent of the time
Yes, subliminal stimuli can be detected unconsciously Priming shows that we can process some information from stimuli below our absolute threshold for conscious awareness. But the effect is too fleeting to enable people to exploit us with subliminal messages.No, subliminal persuasion does not have a powerful enduring effect on behavior
–What is a difference threshold/JND? What is Weber’s law? ‘The minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. Weber’s law is the principle that, to be perceived as different, two stimuli must differ by a constant minimum proportion/percentage (rather than a constant amount)
-What is sensory adaptation? What is a perceptual set? How do expectations, context, and emotions change our perception?
Sensory adaptation is diminished sensitivity as a consequence of constant stimulationPerceptual set is a mental predisposition to perceive one thing and not another Perceptual set is a mental predisposition
–What is the stimulus we “see”? What determines hue? What determines brightness?
Be familiar with these parts of the eye and their functions: pupil, iris, lens, retina- and the path that light waves takes through the eye
The wavelength we see as light is only a tiny slice of a wide spectrum of electromagnetic energy, which ranges from gamma rays as short as the diameter of an atom to radio waves over a mile long. The wavelengths visible to the human eye extend from the shorter waves of blue-violet light to the longer waves of red light. The distance from one wave peak to the next determines its HUE,Intensity, the amount of energy in light waves (determined by a wave’s amplitude, or height), influences brightness. FUNCTIONS ARE 1) Pupil: the adjustable opening in the center of the eye through which light enters 2) Iris: a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening 3) Lens: the transparent structure behind the pupil that changes shape to help focus images on the retina 4) Retina: the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
-What is accommodation?The process by which the eye’s lens changes shape to focus near or far objects on the retina
-What are the differences between rods and cones? See Table 6. 1 What is the fovea?
Rods:retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond.Cones:retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.Fovea:the central focal point in the retina, around which the eye’s cones cluster.
-Why do we have a blind spot? the point at which the optic nerves leave the eye, creating a”blin” spot because no receptor cells are located there
-What are feature detectors? What is parallel processing? FEATURE DETECTORS ARE nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movementthe Parallel processing: the processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions. *studies of patients with brain damage suggest that the brain delegates the work of processing color, motion, form, and depth to different areas. After taking a scene apart, the brain integrates these subdimensions into the perceived image.
-What is a gestalt? What do gestalt psychologists emphasize we perceive? Gestalt:an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes. GESTALT PSYCHOLOGISTS EMPHASIZE that we perceive whole objects or figures rather than isolated bits & pieces of sensory information
-What is figure-ground? Be familiar with the laws of grouping- proximity, continuity, and closure.the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)Figure-ground:the organization of the visual field into objects (the figures) that stand out from their surroundings (theground).Grouping the perpetual tendency to organize stimuli into coherent groupsProximity: we group nearby figures together. We see not six separate lines, but three sets of two lines. Continuity: we perceive, smooth, continuous patterns rather than discontinuous ones. This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines-one wavy, one straight. Closure: we fill in gaps to create a complete, whole object. Thus we assume that the circles on the left are complete but partially blocked by the (illusory) triangle. Add nothing more than little line segments to close off the circles and your brain stops constructing a triangle.
What is depth perception? What is the visual cliff and how is it used to test depth perception? Will crawling infants cross the cliff?
Depth perception is the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance – allows us to estimate an object’s distance from us.a laboratory device for testing depth perception in infants and young animals devisedNO
-What are monocular cues for depth perception? What are relative size, interposition, relative height, relative motion, linear perspective, and light and shadow? See Figure 6.29):
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. Monocular cues: depth cues, such as interposition and linear perspective, available to either eye alone. Relative size: if we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away. Interposition: if one object partially blocks our view of another, we perceive it as closer. The depth cues provided by interposition make this an impossible scene.
Relative height: we perceive objects higher in our field of vision as farther away. Because we assume the lower part of a figure-ground illustration is closer, we perceive it as figure. Invert this illustration and the black will become ground, like a night sky. Relative motion.Linear perspective: parallel lines appear to meet in the distance. The sharper the angle of convergence, the greater the perceived distance Light and shadow:
–What is the stimulus? What determines loudness? What determines pitch?
Stimulusis something that causes a reaction, especially interest, excitement, or energy The amplitude of sound waves determines their loudness. The length, or frequency, determines the pitch we experience. Long-waves have low frequency and low pitch. Short waves have high frequency and high pitch.
– PARTS of the ear and their functions including the middle ear, inner ear, cochlea, and basiliar membrane.
Middle ear the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window Inner ear the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs Cochlea a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
Basilar membrane bends hair cells lining its surface
–How are sound waves converted to a neural impulse? Outer ear, auditory canal, eardrum, middle ear, cochlea, oval window, basilar membrane, hair cells, auditory nerve to the auditory cortex
–What are the two types of hearing loss? How is each treated?
Sensorineural hearing loss:the most common form of hearing loss, also called nerve deafness;caused by damage to the cochlea’s receptor cells or to the auditory nerves Conduction hearing loss:less common form of hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
How do we perceive loudness? P. 259) How do we locate sounds? P. 260
From the number of activated hair cells. Sound waves strike one ear sooner and more intensely than the other. The brain analyzes the minute differences in the sounds received by the two ears and computes the sound’s source.
-What are the two theories of how we perceive pitch? (place theory, frequency theory including the volley principle). Be able to explain each theory and how they might both explain perception of pitch.
Place theory proposes that our brain interprets a particular pitch by decoding the place where a sound wave stimulates the cochlea’s basilar membrane.
Place theory explains how we hear high-pitched sounds, but it cannot explain how we hear low-pitched sounds.
Frequency theory (temporal) proposes that the brain deciphers the frequency of the pulses traveling to the brain. It explains how we hear low-pitched sounds, but not how we hear high-pitched sounds. Some combination of the two helps explain how we we hear sounds in the middle range.
Volley theory neural cells can alternate firing
high pitches place low pitches frequency
-What are the four skin senses?
4 senses are– Pressure, warmth, cold, and pain – that combine to produce other sensations, such as”hot” There is no simple relationship between what we feel at a given spot and the type of specialized nerve ending found there.
-What is gate-control theory and how does it explain how we experience pain? What fibers open the gate? Close the gate? How do biological, psychological factors, and social-cultural factors affect how we experience pain Figure 6.42)? Gate-control theory
the theory that the spinal cord contains a neurological”gat” that blocks pain signals or allows them to pass on to the brain. The”gat” is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.
-Taste- how do we taste? What are the five basic tastes?
Taste, a chemical sense, sense influences it, 5 sensations, – sweet, sour, salty, bitter, and umami.
-What is sensory interaction?
Sensory interaction is the principle that one sense may influence another, as when the smell of food influences its taste
-Smell- how do we smell? How do we experience 10,000 different odors with only 350 different types of receptors (p. 267? Why is smell linked to emotion and memory?
There are no basic sensations for smell… it is a chemical sense.Some 5 million factory receptor cells, with their approx 350 different receptor proteins, recognize individual odor molecules. The receptor cells send messages to the brain’s olfactory bulb, then to the temporal lobe and to parts of the limbic system.Odors can spontaneously evoke memories and feelings, due in part to the close connections between brain areas that process smell and memory.
-What is kinesthesis? The vestibular sense?
The system for sensing the position and movement of individual body parts The sense of body movement and position, including the sense of balance. Comes from the semicircular canals and vestibular sacs in the inner ear
in the inner ear