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Unit Three: Cognition, Sensation, Perception, and States of Consciousness Adapted from: Prentice Hall Psychology Publishing and

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Presentation on theme: "Unit Three: Cognition, Sensation, Perception, and States of Consciousness Adapted from: Prentice Hall Psychology Publishing and"— Presentation transcript:

1 Unit Three: Cognition, Sensation, Perception, and States of Consciousness Adapted from: Prentice Hall Psychology Publishing and andCached

2 Sensation and Perception Sensation: The detection of physical energy emitted or reflected by physical objects; it occurs when energy in the external environment or the body stimulates receptors in the sense organs. Perception: The process by which the brain organizes and interprets sensory information.

3 Ambiguous Figure Colored surface can be either the outside front surface or the inside back surface –Cannot simultaneously be both Brain can interpret the ambiguous cues two different ways

4 Ambiguous Pictures

5 The Riddle of Separate Sensations Sense Receptors: Specialized neurons that convert physical energy from the environment or the body into electrical energy that can be transmitted as nerve impulses to the brain. Doctrine of Specific Nerve Energies: Different sensory modalities exist because signals received by the sense organs stimulate different nerve pathways leading to different areas of the brain.

6 Measuring the Senses Absolute Threshold –The smallest quantity of physical energy that can be reliably detected by an observer Difference Threshold –The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared; also called Just Noticeable Difference (JND).

7 Sensory Adaptations Sensory Adaptation: The reduction or disappearance of sensory responsiveness that occurs when stimulation is unchanging or repetitious. Sensory Deprivation: The absence of normal levels of sensory stimulation.

8 Sensory Overload Selective Attention: The focusing of attention on selected aspects of the environment and the blocking out of others.

9 An Eye on the World Retina: Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision. Rods: Visual receptors that respond to dim light. Cones: Visual receptors involved in color vision. Most humans have 3 types of cones. Dark Adaptation: The process by which visual receptors become maximally sensitive to light.

10 Structures of the Human Eye

11 Structures of the Retina

12 The Visual System is Not a Camera Much visual processing is done in the brain. –Some cortical cells respond to lines in specific orientations (e.g. horizontal) –Other cells in the cortex respond to other shapes (e.g., bulls-eyes, spirals, faces) Feature-detectors: Cells in the visual cortex that are sensitive to specific features of the environment.

13 How We See Colors Trichromatic Theory Opponent Process Theory

14 Trichromatic Theory T. Young (1802) & H. von Helmholtz (1852) both proposed that the eye detects 3 primary colors –red, blue, & green All other colors can be derived by combining these three

15 Opponent-Process Theory A competing theory of color vision, which assumes that the visual system treats pairs of colors as opposing or antagonistic. Opponent-Process cells are inhibited by a color, and have a burst of activity when it is removed. VS

16 Optical Tricks calIllusions/illusions.htm

17 How Culture Influences What We Perceive

18 Perceptual Set Perceptual Set refers to perceptual expectations that make particular interpretations likely to occur and that increase both speed and efficiency of the perceptual process Influenced by personal experience including deprivation e.g., Dawson (1975) and coin size for wealthy and deprived children; Environmental conditions and noise Pollack (1963); kittens in cylinders Blakemore & Cooper (1970) Stress can influence perception and

19 Depiction perceptions are impacted by education; limited education results in misperception of posters (Hudson, 1960) People scan pictures differently based on reading and writing patterns e.g., Hebrew and English speakers use left-to-right strokes for writing and scan the same way; Arab speakers use right-to-left direction for writing and scan the same way Scanning may also be impacted by drawing i.e., directions of drawing circles

20 Depth Perception The organization of sensations in three dimensions Perceiving three dimensional images is confusing for those from extreme poverty and without formal schooling; Education and training can change this (Leach, 1975; Nicholson et al., 1977)

21 Depth and Distance Perception Binocular Cues: Visual cues to depth or distance that require the use of both eyes. –Convergence: Turning inward of the eyes, which occurs when they focus on a nearby object –Retinal Disparity: The slight difference in lateral separation between two objects as seen by the left eye and the right eye. Monocular Cues: Visual cues to depth or distance that can be used by one eye alone.

22 Visual Constancies The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce. –Shape constancy –Location constancy –Size constancy –Brightness constancy –Color constancy

23 Visual Illusions Illusions are valuable in understanding perception because they are systematic errors. –Illusions provide hints about perceptual strategies In the Muller-Lyer illusion (above) we tend to perceive the line on the right as slightly longer than the one on the left.

24 Fooling the Eye The cats in (a) are the same size The diagonal lines in (b) are parallel You can create a “floating fingertip frankfurter” by holding hands as shown, 5-10” in front of face.

25 Are People Equally Misled by Visual Illusions? Non-Western and rural participants showed less susceptibility to the Ponzo illusion than Western and urban areas (Brislin, 1993) Carpentered world hypothesis (Segall et al., 1966) people who are raised in an environment made by carpenters tend to interpret nonrectangular figures as representations of rectangular figures seen in perspective Language impacts the labeling of colors and Europeans may lack words to describe vivid colors (Berry et al., 1992)

26 Certain visual perceptual skills might be related to things like retinal pigmentation (Pollack, 1963) Colors may be more salient for political reasons e.g., red-China, perception of black and white in the U.S. and in other countries as bad and good (Best et. al., 1975; Williams & Best, 1990) –Jung saw this as a reflection of unpredictability and that nature may have endowed humans with this susceptibility

27 Hearing Variations in hearing are due to physiological differences caused by age, education training, environmental conditions, and experience

28 Taste Although people are capable of tasting sweet, sour, salty and bitter, people living near the equator prefer spicier foods than people in the north or south

29 Smell Underarm secretions may impact the menstrual cycle (Cutler, 1986)

30 Touch Touch is about pressure, temperature, and pain –Anxiety increases pain –Fear, anger, or stress inhibits it Prioreceptive sense helps people determine body position and movement

31 The Environment Within Kinesthesis: The sense of body position and movement of body parts; also called kinesthesia. Equilibrium: The sense of balance. Semicircular Canals: Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head.

32 Perception of Time Westerners tend to define time w/ precise measurement Mediterranean Arabs have 3 types of time i.e., no time at all, now, and forever –Akbar (1991) sees Westerners emphasizing time as a commodity bought and sold for consumption, but in Africa time connects all e.g., Swahili sasa indicating immediacy and zamani indicating a warehouse of time including the ancestors

33 People who feel time pressure move faster than those who don’t e.g., Tokyo 20.7 seconds to cover 100’, London 21.6; New York 22.5; Jakarta 27.2 (Levine & Wolff, 1992) –Some studies indicate age seems to bring a release from those constraints, but this research is inconsistent

34 Consciousness and Culture Consciousness refers to subjective awareness of one’s own sensations, perceptions and other mental events; Consciousness is reflected in the beliefs of Moslems, Jewish, Christian, Hindu, Buddhist and other thoughts –Monists believe body and soul are inseparable –Dualists believe body and soul are independent

35 Additional Ideas Individual consciousness may be dependent on cultural factors (Piaget, 1963; Vygotsky, 1932; Wundt, 1913) Hallowell (1955) thought people lived within a behavioral environment i.e., a mental representation of time space, and the interpersonal world e.g., Ojibwa Indians whose behavioral environment included self, others, gods, relatives and deceased ancestors therefore, when contemplating a moral action, they think of possible impacts on all including dead ancestors

36 Consciousness in the West Not necessarily linear –Existentialism & symbolism in literature Marquez’s Cien Años de Soledad –Cubism and primitivism in painting –Modernism in music

37 Sleep and Cultural Significance of Dreams Sleep is a nonwaking state of consciousness characterized by general unresponsiveness to the environment and general physical immobility –Responsiveness to external stimulation diminished Dreams are story-like sequences of images occurring during sleep

38 Bourguignon (1954) Monophasic cultures value cognitive experiences that take place only during normal waking phases and don’t incorporate dreams into social perception and recognition –Associated with materialistic worldview on psychological experience Polyphasic cultures value dreams and treat them as part of reality –Associated with the spiritual or traditional view

39 What are dreams? People used to view dreams as messages from God or as omens of the future Today we study them as psychological events Freud was particularly interested in dreams and dream interpretations

40 Dreams tend to reflect expectations Different cultures view the purpose of dreams differently i.e., as some sort of spiritual information or as latent content reflecting soicocultural reality

41 Types of Dreams Recurring Dreams –Happen repeatedly –Usually relates to a personality issue, insecurity, or sometimes a preoccupation (something you think about a lot or are very concerned with) Predictive Dreams –‘déjà vu’ type dreams where you dream about something that eventually occurs –Unproven and unreliable

42 Types of Dreams (Cont.) Lucid Dreams –Dreaming while knowing that you are dreaming –Sometimes you can control what happens in your dream –Two Levels of lucid dreams ‘High Level’ = Dreamer is aware he/she is dreaming and asleep in bed… knows characters and situations aren’t real ‘Low Level’ = Dreamer is aware he/she is dreaming, but not that he/she is asleep and safe in bed. Often think that dreams and characters are real.

43 Nightmares and Night Terrors Nightmares –Scary or violent dreams that result from some anxiety which bursts through into dreams –Especially in childhood –Often can relate to past experiences which still cause concern or anxiety –Occur during REM sleep & are usually remembered

44 Nightmares and Night Terrors Night Terrors –Occur during Stage 4 of NREM sleep & are not remembered –Can’t wake someone up from a night terror… usually takes minutes to wake them –Usually not a situation, just panic that strickes while sleeping and accompanied by movement and screams –Children ages 2-6 have these the most common

45 Freud’s Dream Symbolism ItemRepresented by… Because of…Examples… Female Genitalia and Sexuality Hollow objects that contain things Physical design of a vagina Boxes, suitcases, tin cans, bottles, caves, pits, etc. Houses with entrances or hallways Sexual role of vagina Churches, steeples, castles, mansions, etc. Wood & paper objects Miscellaneous reasons Newspapers, wood furniture, cards, tissue, etc. FruitBreastsApples, peaches, etc. Animals with shells MiscellaneousSnails, mussels, clams, etc.

46 Freud’s Dream Symbolism ItemRepresented by… Because of…Examples Male Genitalia and Sexuality The Number 33 parts- two testicles & penis Three parts to the dream, three characters, etc. Things that stick out Similar/form shape Mountain, rocks, sticks, umbrellas, poles, trees, etc. Things from which water or liquid flow EjaculationPipes, fountains, watering cans, faucets, etc. Things which are used to penetrate or harm Sex/RapeKnives, swords, guns, cannons, daggers, etc. AnimalsMiscellaneous (shape) Reptiles, snakes, etc.

47 More Dream Analysis ItemRepresented by…Because of… MasturbationSliding, slipping & breaking branches Physical design CastrationTeeth falling out or being extracted Loosing an essential part of the body Sexual intercourseActivities like riding, climbing & raising a weapon Miscellaneous reasons (similar actions) FamilyKing & QueenPower, domination, etc.

48 Beyond Altered States of Consciousness Altered States of Consciousness (ASC) refers to phenomena that are different from waking consciousness and include mystic perceptual and sensory experiences like meditation, hypnosis, trance and possession (Ward, 1994) Trance is a sleeplike state with reduced sensitivity to stimuli, loss or alteration of knowledge and automatic motor activity –Mass religious ceremonies, collective prayers, rock concerts, political gatherings can result in trances

49 Trances Visionary trances are when someone experiences hallucinations –More common in men of hunter-gatherer societies Possession trances are when someone reports that their body has been capture by one or more spirits –More common in women of non-hunter- gatherer societies –Mass hysteria e.g., Lee & Ackerman (1980) West Malaysia college; Salem witches

50 Meditation A quiet and relaxed state of tranquility where a person achieves an integration of thoughts, perceptions, and attitudes –Looking for liberation from self or an expansion of conscious awareness –Can reduce stress

51 What Is Sleep? An altered state in which people become relatively unaware of external stimulation

52 Studying Sleep (1953) EEG records brain wave activity – Frequency and strength EOG record eye movements EMG record muscle movements EKG records activity of the heart

53 EEG and Sleep Stages Awake = Beta Waves Stage 1 = Theta Waves – Hypnagogic State Stage 2 = Theta Waves – Sleep Spindles Stage 3 = Delta Waves Stage 4 = Delta Waves – Bedwetting, Sleep talk/walk – Night Terrors REM = Mimic’s Beta Waves – Atonia, DREAMING!

54 Sleep Cycle Roughly 5 periods of REM sleep per night – Sleep becomes lighter as night wears on – REM sleep becomes longer towards am

55 Why Do We Sleep? Evolutionary Theory: Protective function, keeps people tucking away at night, safe from predators. Recuperative Theory: Conserves energy, restores body tissues depleted during daily activity – REM: hormones released that influence thinking & memory formation, mental organization; counteract fatigue, irritability, inattention – NREM: body replenishes itself (tissue restoration and release of growth hormone)

56 Why Do We Sleep At Night? Circadian Rhythm – Internally generated sleep/wake cycle connected to 24-hour pd of earth’s rotation

57 How Much Sleep Do I Need? Infants – 20 hours 50% REM Children/Adolescents – 10 hours 25-30% REM – Bed Later, Up Later Adults – 8 hours 20% or less REM Elderly – 6 hours – Bed Later, Up Earlier

58 What If I Miss Sleep? Effects On Body – Immune system weakens – Metabolic malfunction – Varied body temp Effects On Brain – Moodiness – Decreased cognitive performance Learn slower, remember less, loss concentration & creativity – Blurred vision – Disorganized speech – Hallucinations

59 Am I Sleep Deprived? Yes/No I need an alarm clock to wake up for school. It’s a struggle to get out of bed in the morning. I hit the snooze bar several times to get more sleep. I feel tired, irritable and stressed out during the week. I have trouble concentrating and remembering. I feel slow with critical thinking, problem solving and being creative. I often fall asleep in boring classes or warm rooms. I often fall asleep within 5 minutes of getting into bed. I often feel drowsy while driving. I often sleep extra hours on weekend mornings. I often need a nap when I get home from school. I have pink circles around or dark circles under my eyes.

60 Am I Sleep Deprived? Yes/No An answer of “yes” to three or more of the previous questions indicates sleep deprivation. You can easily improve your mood, performance and health by getting more sleep !

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