1. Sensation & Perception Chapter 5

2. Sensation & Perception The “five” senses: – sight, hearing taste, smell, touch, vestibular & kinesthetic Sensory organs receive stimuli Process: external stimulus chemical-electrical message – (neural impulse) interpreted by the brain TRANSDUCTION!

3. Sensation & Perception – Sensation is the activation of the senses and perception is the process of understanding these sensations. Sensory adaptation – decreasing responsiveness to stimuli due to constant stimulation. (Shoes) – Neurons stop firing – eyes quiver! Sensory habituation – How focused we are on a particular stimuli. (Peripheral vision) Cocktail party phenomenon – An involuntary switch of perception.

6. Sensation & Perception Psychophysics – the study of how physical energy relates to psychological experience. Absolute threshold – the minimum stimulation needed to detect a particular stimulus 50% of the time. – Sight, smell, touch, hearing, taste – (hearing tests) Signal detection theory – a theory predicting how & when we detect the presence of a faint stimulus (signal). Subliminal stimulation – “below the threshold” – Coke & Popcorn – Backtracking – Audio tapes

7. Difference threshold – JND Just Noticeable Difference - the minimum difference a person can detect between any two stimuli half the time. Webers Law – to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount). (Usually about 8%)

8. Sensory & Perception Top down processing – brain to senses! Bottom up processing – senses to brain!

9. Vision Cornea Pupil Iris Lens Retina Photoreceptors Optic nerve Occipital lobe

14. Photoreceptors – Cones & Rods Fovea Blind spot Optic nerve Occipital Lobe

17. The “Chemical Senses” Olfactory – Humans 10-20 million receptor cells – Dogs 200 million receptor cells – Highly associated with memory – Anosmia – the inability to smell

18. Smell - Olfactory

19. Taste The four experiences of taste are – A. sour – B. salty – C. bitter – D. sweet Flavor is composed of – A. taste – B. smell – C. tactile sensations Label the areas of sensitivity on the Tongue…

21. Touch Sense The four kinds of information provided by the skin are: – Pressure – Warmth – cold – Pain What is the purpose of pain? What is the gate control theory of pain?

22. Perception Perception – the process by which the brain receives information from the senses and organizes and interprets it into meaningful experiences – unconsciously. Selective attention – the focusing of conscious awareness on a particular stimulus (cocktail party effect). Inattention blindness – failing to see visible objects when our attention is directed elsewhere.

23. Change blindness, 2, 3 Change blindness23 Perceptual illusions

26. Is the Gateway Arch of St. Louis higher or wider?

28. Which line is longer?

29. Perceptual Organization Figure Ground – the organization of the visual field into objects (figures) that stand out from their surroundings (ground). Gestalt – an organized whole. We have a tendency to integrate pieces of information into meaningful wholes. Gestalt principles – – Proximity, similarity, continuity, connectedness, closure

34. Proximity

35. Similarity

36. continuity

37. connectedness

38. closure

42. Depth Perception The ability to see objects in three dimension. Visual cliff – Nature v. Nurture? Binocular cues – Retinal disparity – convergence

43. Monocular Clues Relative size Interposition Relative clarity Texture gradient Relative height Linear Perspective Light & Shadow

44. Relative size

45. Linear Perspective

46. Light & Shadow

47. Interposition

48. Linear

50. Relative Height