PS101 2 nd Midterm Exam-AID

1. PS101 2nd Midterm Exam-AID Course Coordinator: Ariel Ho Tutor: Marla Lampert

2. Agenda • Chapter 4: Sensation and Perception • Chapter 5: Variations in Consciousness • Chapter 12: Personality

3. Chapter 4

4. Sensation and Perception • Sensation is the stimulation of sense organs • Perception is the selection, organization, and interpretation of sensory output

5. Psychophysics The study of how physical stimuli are translated into psychological experience

6. Psychophysics • Absolute threshold • Minimum amount of stimulation needed for an organism to detect a stimulus 50% of the time • For example, the absolute threshold of human vision is a candle flame seen at 50km on a dark, clear night 50 km

7. Psychophysics • The JND (Just Noticeable Difference) • Smallest difference in the amount of stimulation that a specific sense can detect • An absolute threshold is simply the JND from nothing (no stimulus input) • Weber’s Law • The size of a JND is a constant proportion of the size of the initial stimulus • As stimuli increase in magnitude, the JND becomes larger

8. Absolute Threshold is: a) Minimum amount of stimulation needed for an organism to detect a stimulus 50% of the time b) Minimum amount of stimulation needed for an organism to detect a stimulus 100% of the time c) The Just noticeable difference from no stimulus input d) A and C e) B and C

9. Psychophysics • Fechner’s Law • The magnitude of a sensory experience is proportional to the number of JNDs that the stimulus causing the experience is above the threshold • Perceptions can’t be measured on absolute scales Change in perceived intensity = f ( change in stimulus / current stimulus )

10. Psychophysics • Signal detection theory • Detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity • Your responses will depend in part on the criterion you set for how sure you must feel before you react

11. Present-Present is to Hit, as Absent-Absent is to ________: • False Alarm • Miss • Correct Rejection • Hit

12. Psychophysics • Subliminal Perception • The registration of sensory input without conscious awareness

13. Psychophysics • Sensory Adaptation • Gradual decline in sensitivity to prolonged stimulation • For example: • You are stressed out about exams and forgot to throw out your garbage that had a piece of mouldy cheese in it. When you come back in your room it smells awful, but if you sit in your room for a long enough amount of time, you will barely be able to smell it (your sensitivity decreases)

14. Our Sense of Sight • The stimulus is light • Light is a form of electromagnetic radiation that travels as a wave, moving, naturally enough, at the speed of light Wave Amplitude Wavelength

15. A vary large wavelength will result in you seeing: • Red • Indigo • A very bright colour • A very rich colour

16. Our Sense of Sight • The eye • Channels light to the neural tissue that receives it (the retina) and houses that tissue • The cornea and lens form an upside down image of objects on the retina, but the brain fixes this • The lens focuses the light rays falling on the retina • Nearsightedness: close objects are seen clearly but distant objects appear blurry (farsightedness is the exact opposite) • The pupil is the opening in the centre of the iris that helps regulate the amount of light passing into the rear chamber of the eye

18. Which part of the eye produces an upside down image of objects on the retina? • The Cornea • The Lens • The Optic Nerve • A and B • All of the above

19. OurSense of Sight • The Retina • The neural tissue lining the inside back surface of the eye • Absorbs light, processes images, and sends visual information to the brain • Piece of central nervous system • The axons that run from the retina to the brain converge at the optic disk

20. Our Sense of Sight • The Retina • Cones are specialized visual receptors that play a key role in daylight vision and colour vision • Concentrated in the centre of the retina (the fovea) • Rods are specialized visual receptors that play a key role in night vision and peripheral vision • Dark Adaptation is the process in which the eyes become more sensitive to light in low illumination (and vice versa for light adaptation)

21. Our Sense of Sight • Info processing in the retina • Receptive field of a visual cell is the retinal area that, when stimulated, affects the firing of that cell • Centre-surround arrangement • When stimulated, retinal cells send signals both toward the brain and laterally (sideways) toward nearby visual cells • Lateral Antagonism occurs when neural activity in a cell opposes activity in surrounding cells • allows visual system to compute the relative amount of light at a point instead of reacting to absolute levels of light  contrast

22. The retina has a centre-surround arrangement, and therefore when more light falls in the centre, _______: • There is an increased rate of firing • There is a decreased rate of firing • The cell fires at its baseline rate • The rate increases, then decreases

23. Our Sense of Sight • Vision and the Brain • Travel from optic nerves to the Optic chiasm, the point at which the optic nerves from the inside half of each eye cross over and then project to the opposite half of the brain • Then either go to • the thalamus (most common) • Engage in parallel processing • An area in the midbrain (superior colliculus) • Coordinatination of visual input with other sensory output

25. Our Sense of Sight • Colour • 2 kinds of colour mixture: additive and subtractive • The trichomatic theory of colour vision: 3 receptors that combine through additive colour mixing • The opponent process theory are pairs of receptors that work antagonistically

26. According to the Opponent Process Theory, When red fires, ____ is inhibited: • Blue • Green • Yellow • Black

27. Our Sense of Sight • Reversible figure is a drawing that is compatible with two interpretations that can shift back and forth

28. Our Sense of Sight Recognize Stimulus Combine Specific Features into more complex forms Detect Specific Features of Stimulus Top-down Processing Bottom-up Processing

29. You recognize your mother’s face before you recognize the individual features of it, such as her mouth, eyes, nose, etc. This is an example of: A) Left- Right Processing B) Right- Left Processing C) Bottom- Up Processing D) Top- Down Processing

30. Our Sense of Sight • Gestalt Principles • Figure and ground • Proximity • Closure • Similarity • Simplicity • continuity

31. Our Sense of Sight • Perceptual Hypothesis • Inference about which distal stimuli could be responsible for the proximal stimuli sensed • Distal stimuli • Stimuli that lie in the distance (eyes don’t “touch” them) • Proximal stimuli • distorted, 2D versions of their actual, 3D counterparts

32. Our Sense of Sight • Depth Perception • Interpretation of visual cues that indicate how near or far away objects are • Binocular and monocular cues

33. Our Sense of Sight • Optical Illusion involves an apparently inexplicable discrepancy between the appearance of a visual stimuli and physical reality

34. Our Sense of Sight • Impossible figures are objects that can be represented in 2D pictures but cannot exist in 3D space

35. This Picture helps explain the concepts Of: • Depth Perception • Optical Illusion • Impossible Figure • All of the above

36. Our Sense of Hearing • The stimulus: Sound • Amplitude is the principal determinant of loudness, but loudness ultimately depends on an interaction between amplitude and frequency

37. OurSense of Hearing • External Ear • Depends on vibration of air molecules • pinna • Middle Ear • Depends on vibration of movable bones • ossicles • Inner Ear • Depends on waves in a fluid • Cochlea, Basilar membrane

38. Our Sense of Hearing • Theories on pitch perception • Place theory • Perception of pitch corresponds to the vibration of different portions, or places, along the basilar membrane • Frequency theories • Perception of pitch corresponds to the rate, or frequency, at which the entire basilar membrane vibrates • Localization • Locating the source of sound in space

39. You are sitting in your dorm room and hear voices talking about the leaf’s game and want to join in. Due to ____, you know that the voices are coming from the room to your left, not right. • Place theory • Frequency theory • Localization • Pitch theory

40. Our Chemical Senses • Taste: The Gustatory System • Physical stimuli: Chemical substances • Psychological stimuli: Taste sensations (sour, sweet, salty, and bitter) • Taste buds perceive all 4 sensations, but respond more to 1 of the 4 • Some basic taste preferences appear to be innate, though taste preferences are largely learned and heavily influenced by social processes

41. Our Chemical Senses • Taste: The Gustatory System • Gustatory receptors are clusters of taste cells found in the taste buds • When these cells absorb chemicals dissolved in saliva, they trigger neural impulses that are routed through the thalamus to the cortex

42. Our Chemical Senses • Smell: The Olfactory system • Physical = chemical molecules • Psychological = too many to classify (over 10000 smells that people can smell) • Receptors for smell are olfactory cilia • Smell is the only sensory system in which incoming information is not routed through the thalamus before it projects to the cortex

43. In what way(s) is the sense of taste like the sense of smell? • There are 4 primary stimulus groups for both senses • Both systems are routed through the thalamus on the way to the cortex • The physical stimuli for both senses are chemical substances dissolved in fluid • All of the above • None of the above

44. Our Sense of Touch • Physical = mechanical, thermal, and chemical energy that impinge on the skin • Psychological = warm/cold, pressure/pain, position/movement • Feeling pressure • The nerve fibres that carry incoming information about tactile stimulation are routed through the spinal cord to the brainstem, then thalamus, then somatosensory cortex

45. Our Sense of Touch • Feeling Pain • Fast and slow pathways to the brain • Perception can be influenced greatly by expectations, personality, mood, etc. • Gate control theory • Incoming pain sensations must pass through a “gate” in the spinal cord than can be closed, thus blocking ascending pain signals

46. Our Other Senses • Kinesthetic System • Monitors the positions of the various parts of the body • Vestibular system • Responds to gravity and keeps you informed of your body’s location in space • Provides sense of balance, compensating for changes in the body’s position • Shares space in inner ear with the auditory system

47. You take the 7C bus to Connestoga mall to buy a gift for your friend’s birthday. You end up having an aggressive bus driver who likes to drive really fast over potholes, and you must stand up because there are no more seats. Therefore your body is moving a lot inside the bus, yet when you look out the window, everything looks normal and not moving around. This is due to your: • Kinaesthetic System • Olfactory System • Vestibular System • Gustatory System

48. Chapter 5

49. The Nature of Consciousness • Consciousness is the awareness of internal and external stimuli • Awareness of external events • Your awareness of your internal sensations • Your awareness of your self as the unique being having these experiences • Your awareness of your thoughts about these experiences

50. The Nature of Consciousness • According to Freud, there are different levels of awareness • The EEG summarizes the rhythm of cortical activity in the brain in terms of line tracings called brain waves that vary in amplitude and frequency