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PSYCHOLOGY 1011 MIDTERM REVIEW

PSYCHOLOGY 1011 MIDTERM REVIEW. Meredith Bessey Rachel Grant. CHAPTER 5: SENSATION AND PERCEPTION. How do sensation and perception differ? Sensation is the stimulus detection itself, perception is making sense of these stimuli

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PSYCHOLOGY 1011 MIDTERM REVIEW

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  1. PSYCHOLOGY 1011 MIDTERM REVIEW Meredith Bessey Rachel Grant

  2. CHAPTER 5: SENSATION AND PERCEPTION • How do sensation and perception differ? • Sensation is the stimulus detection itself, perception is making sense of these stimuli • Different sensory impulses are processed by different brain regions, which results in different perceptions Physiological Response Sensory experience Physical Stimulus

  3. PSYCHOPHYSICS • Psychophysics is the relationship between physical stimuli and the sensations we have about them • Psychophysicists study detection and discrimination • Detection is the limits of sensitivity for us to detect a stimuli • Discrimination is how much two stimuli have to differ for us to detect the difference • Detection (sensory) threshold is the quantitative amount of a stimulus required for it to be detected • How is this measured? Method of constant stimuli • Absolute threshold is the lowest intensity at which a stimuli can be detected 50% of the time

  4. STIMULUS DETECTION • Why is a stimuli detected some of the time, but not all of the time? • Difference threshold: also called just noticeable difference (JND), the amount a stimulus must vary for us to detect a difference 50% of the time • Tested by presenting a standard stimulus and comparison stimuli of varying amounts, is the comparison stimulus different than the standard?

  5. SIGNAL DETECTION THEORY • people set their own standard of how certain they must be of a stimulus to say they detect it, there is no fixed absolute threshold that is true of all people

  6. VISION: PARTS OF THE HUMAN EYE

  7. VISION... • Pupil changes size by dilating or constricting the control amount of light entering eye • Lens is behind pupil and thickens to focus on closer objects and becomes thinner to focus on distant objects • Why do you need eye glasses or contact lenses? • Myopia = nearsightedness, lens focuses the image too close to the lens and in front of the retina • Hyperopia = farsightedness, lens focuses the image too far from lens and behind the retina

  8. RETINAL IMAGE = UPSIDE DOWN?

  9. VISION • Layers of the retina • Photoreceptors = detect different lights (rods = black and white and cones = colour), make up rear layer of retina • Bipolar cells = photoreceptors send signals to these cells, which in turn send signals to ganglion cells • Ganglion cells = axons are bundled into optic nerve, which exits the back of the eye creating the blind spot

  10. VISION... • How does the visual acuity of the fovea and periphery differ? • Fovea = high visual acuity because of density of cones and small receptive fields • Periphery = low visual acuity because of density of rods and large receptive field • What is visual transduction? • It is the process through which a stimulus (in this case light) gets transferred into a nerve impulse

  11. LIGHT AND COLOUR • Theories of colour vision • Trichromatic theory • Three types of cones, each maximally responsive to different wavelengths of light • Opponent-process theory • Dual process • Visible light is only small part of spectrum (400-700)

  12. THEORIES OF COLOUR VISION • Opponent process theory in more detail • Ganglion cells either increase (ie. in response to red) or decrease (ie. in response to green) their rate of firing in response to opponent colours • Blue-yellow, red-green, black-white • Dual process theory – both trichromatic theory and opponent process theory are RIGHT! • Trichromatic theory operates at the level of cone cells  maximally sensitive to blue, green or red light • Opponent-process theory operates further along in the visual system and in the visual cortex • Colour blindness  dichromats and monochromats

  13. HEARING • Human’s hearing sensitivity ranges from 20 to 20,000 Hz  greatest sensitivity around 2000 to 4000 Hz (FREQUENCY) • Amplitude = volume • Higher amplitude = higher volume • Lower amplitude = lower volume • Frequency = pitch • Higher frequency = higher pitch • Lower frequency = lower pitch

  14. PARTS OF THE EAR • Pinna = visible part of the ear • Auditory canal = ends at the ear drum • Ear drum = vibrates in response to soundwaves • Three ossicles • Hammer, anvil, stirrup • These bones vibrate and amplify sound waves • Cochlea = coiled, fluid shape tube • Organ of corti = rests on top of the basilar membrane, thousands of hair cells embedded in it (sound receptors) • Basilar membrane = site of transduction, vibrates in response to sound

  15. PARTS OF THE EAR CONT... • Tectorial membrane = lies on tips of hair cells along entire length of cochlea • Hair cells = synapses with neurons of auditory nerve, which relays information to thalamus and to auditory cortex • Process of sound transduction • Sound waves strike eardrum • Pressure sets cochlea into motion • Basilar and tectorial membrane vibrate and hair cells bend • Neurotransmitter is released from hair cells • Nerve impulse is sent to brain

  16. CODING SOUND • High frequency sounds coded near round window and low frequency sounds coded near oval window • Place theory = frequency of sound is indicated by place on the organ of Corti that has the highest firing rate • Vibrating motion of basilar membrane is a travelling wave

  17. SOUND LOCALIZATION • Sound is localized based on intraaural difference (ie. distance between your two ears) • ie. sounds to the left will reach the left ear before the right ear, deduce that sound is coming from the left • Two types of deafness • Conduction deafness • Nerve deafness

  18. CHEMICAL SENSE: TASTE & SMELL • These senses rely on chemical molecules, not a wave source of ‘energy’ • Taste buds are chemical receptors  made up of several receptor cells • Clustered along edges and back of tongue, and back and roof of mouth • Hairlike structures project into taste pore • Food dissolves in saliva, which spreads into taste pore to activate receptors • Five qualities of taste: sweet, salty, sour, bitter, umami

  19. SMELL • Olfactory receptors = long cells on cilia that project to mucous membrane and line upper nasal cavity • Receptors send messages to olfactory areas in the brain  project directly to brain (different from all other systems) • Neurons project to olfactory brain through cribiform plate (often get sheared off in head injuries) • Pheromones • Chemicals found in natural body scents • Can affect behavior in subtle ways • ie. menstrual synchrony

  20. TOUCH • 4 main tactile sensations = pressure, pain, warmth, and cold • Primary receptors for pain and temperature are free nerve endings  simple nerves beneath the skin’s surface

  21. Somatosensory homunculus • Areas that have more sensitivity to stimulation are well represented (ie. lips, hands, tongue)

  22. BODY SENSES • Kinesthesis • feedback about muscle and joint positions • Receptors = nerve endings in muscles, tendons, and joints • Vestibular sense • Information about position of body • Sense of body orientation or equilibrium • Receptors in vestibular apparatus of the inner ear

  23. GROUPING PRINCIPLES

  24. FIGURE GROUND RELATIONSHIP • We have a strong tendency to divide any image into a figure and the background

  25. PERCEPTUAL CONSTANCIES • Size, orientation, lighting • Perceive the same object despite changes that makes these images on our retina VERY different • Allows us to recognize people and objects when we see them from different angles, during the day versus at night etc.

  26. DEPTH PERCEPTION • Monocular cues • Size • Linear perspective • Atmospheric perspective • Overlap • Height cues • Among others... • binocular cues • Convergence • Retinal disparity

  27. Questions?

  28. CONSCIOUSNESS Chapter 6…

  29. PUZZLE OF CONSCIOUSNESS Consciousness—moment to moment awareness of ourselves and our surroundings CONSCIOUSNESS  ATTENTION Selective Attention—focusing attention on those things you consider important

  30. QUANTIFYING ATTENTION Self-report—people describe their own inner experiences Physiological—measuring brain activity during a task Behavioural—performace task

  31. FREUD’S PSYCHODYNAMIC THEORY OF AWARENESS CONSCIOUS MIND PRECONSCIOUS MIND UNCONSCIOUS MIND

  32. COGNITIVE THEORY CONSCIOUS vs. UNCONSCIOUS Controlled processing—voluntary use of attention Automatic processing—can be performed with little to no effort Divided attention—multi-tasking

  33. CIRCADIAN RHYTHMS Pineal Gland Melatonin Relaxation

  34. DAY NIGHT SCN—inactive Pinal Gland Melatonin = Relaxation/ Sleepiness SCN—active Pinal Gland Melatonin =Alertness

  35. DISRUPTIONS IN CIRCADIAN RHYTHMS Gradual and sudden environmental changes can disrupt our circadian rhythms • Seasonal Affective Disorder • Jet Lag • Night shift work Treatments? Melatonin Treatments

  36. STAGES OF SLEEP

  37. WHY SLEEP? • Restoration Model Re-charge our run down bodies Adenosine prepares us for sleep after a long, busy day Caffeine • Evolutionary Model Increase our chance of survival in demanding environment • Memory Consolidation Increased brain activity during sleep REM sleep strengthens neural circuits

  38. SLEEP DISORDERS • Insomnia—chronic inability to fall asleep, maintain, or experience restful sleep • Narcolepsy—inability to stay awake • REM-Sleep Behaviour Disorder—loss of muscle tone that causes normal REM sleep paralysis is absent • Sleep Apnea—irregular breathing during sleep • Sleepwalking—during stage 3 or 4 of sleep • Nightmares—frightening dreams experienced by most of the population • Night terrors—intense nightmares that produce arousal and a near terrified state

  39. WHY DREAM? • Freud’s Psychodynamic Theory • Activation-Synthesis Theory • Cognitive-Process Dream Theory No agreed upon model of dreaming, but there have been different suggestions about how to combine ideas from the 3 concepts.

  40. DRUGS

  41. ADMINISTRATION OF DRUGS • Most drugs are absorbed through capillaries • Psychoactive drugs act on the brain and therefore must cross the Blood-Brain Barrier

  42. NEUROTRANSMISSION IS KEY TO UNDERSTANDING HOW DRUGS WORK

  43. DRUGS MAY FACILITATE OR INHIBIT SYNAPTIC TRANSMISSION

  44. WHAT HAPPENS WITH CONTINUOUS USE? • Tolerance—decreased responsiveness of a drug with repeated use • Compensatory response—way body tries to reduce the action of drug • Homeostasis—inner balance within your body • Withdrawal—body’s response to lack of exposure to drug

  45. WHAT ABOUT ADDICTION? • Addiction: compulsive drug use with the loss of control over drug intake despite negative consequences

  46. PSYCHOLOGICAL EFFECTS OF DRUGS • Reinforcement—promotes the behaviour • Positive • Negative • Punishment—discourages the behaviour • Positive • Negative …Natural vs. Not-so-natural reinforcements

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