1. Sensation and Perception
Ciccarelli and White
Chapter 3
Introductory Psychology Spring 2014

2. Sensation and Perception
Sense- a system that translates outside information into activity in the nervous system
Sensation- the stimulus message coming from the senses
Transduction- process of converting stimuli
Perception- the process of giving meaning to that message

3. Figure: What Do You See?

4. ABC’s of Sensation
Sensation is the activation of receptors in the various sense organs
Sensory Receptors
Specialized forms of neurons
Not stimulated by other neurons
Stimulated directly by different kinds of energy (light waves, sound waves, etc)

5. Sensory Energy
Wavelength- the distance between peaks in a wave of light and sound
Frequency- number of complete waves, or cycles, that pass a given point per unit of time
Amplitude- the distance between the peak and the baseline of a wave

6. Figure: The Dimensions of a Wave

7. Sensory Systems- How Information gets from Sensation to Perception
Your senses gather information through various forms of energy
This energy is encoded into neuronal activity
Neuronal activity relays signals to the brain

8. Modification of Energy into Neuronal Activity
In some sensory systems the first step in sensation involves modifying the incoming stimulus
Accessory structures complete this modification
The second step in modification is transduction
Transduction is the process of converting incoming energy into neuronal activity
Transduction takes place at structures called receptors

9. Transfer of Information through CNS
Coding translates the physical properties of a stimulus into neural activity
Sensory nerves transfer coded activity to the brain (Thalamus)
Coded information for all senses except smell goes to the Thalamus
Thalamus does some initial processing and sends information to the Cerebral Cortex
Cortex receives input and produces sensation and perception

10. Review of Structures of Forebrain

11. Review: Elements of a Sensory System

12. Sensory Threshold Habituation and Sensory Adaptation
Sensory Thresholds
Weber’s Law of just noticeable differences
Ex: Sugar in Coffee (20%)
Already have 5 teaspoons, must add 1 teaspoon
Already have 10 teaspoons, must add 2 teaspoons
Coffee regular
Absolute Threshold
Subliminal Perception
Movie
Habituation and Sensory Adaptation

13. The Science of Seeing The Science of Seeing
Psychological Properties of Light
Three psychological aspects to light
Brightness
Color
Saturation

14. Figure: The Spectrum of Electromagnetic Energy

15. Structures of the Eye The structure of the eye Cornea Aqueous humor
Iris
Pupil
Lens
Vitreous humor
Retina
Cones
Rods
Fovea
Optic Nerve
Blind Spot/ Optic Disc

16. Figure: Major Structures of the Eye

17. Figure: The Lens and the Retinal Image

18. How the Eye Works Left and Right Visual Fields Areas of the Retinas
Where the information goes
Optic chiasm
Photoreceptors
Rods
Dark adaptation
Light adaptation
Cones

19. Color vision Color Vision Trichromatic Theory The Afterimage
Opponent-process theory
Lateral geniculate nucleus
Color Blindness

20. Stare at the dot for seconds and then look at a white piece of paper—you should see the flag in the appropriate colors
You need to stare until your eyes are fatigued
Go to the next page (Blank page-slide 22) and then return to color vision slide (slide 20)

22. Perception of Sound What is sound Properties of sound waves
Auditory Spectrum

23. The Structure of the Ear
The outer ear
The Middle ear
The inner ear
Cochlea
Basilar Membrane-resting place of the organ of Corti
Organ of Corti- contains receptor cells for the sense of hearing
Auditory Nerve- bundle of axons from the hair cells in the inner ear that run to the brain

24. Figure: Structures of the Ear

25. Figure: The Cochlea

26. Perceiving Pitch Theories of Pitch
Pitch- psychological experience of sound that corresponds to the frequency of the sound waves; higher frequencies are perceived as higher pitches
Place Theory
Frequency Theory
Volley Principle

27. Types of Hearing Impairments
Conduction Hearing Impairment
Hearing aids
Nerve hearing impairment
Tinnitus
Cochlear implants

28. Figure: Sound Waves and Waveforms

29. Table: Intensity of Sound Sources

30. Auditory Pathways to the Brain
Auditory nerve conveys information to the thalamus which then relays it.
Thalamus relays the information to the primary auditory cortex
Cells in the auditory cortex have preferred frequencies.
Auditory cortex also receives information from other senses.

31. Chemical Senses Chemical Senses Gustation Olfaction Taste buds
Five basic tastes
Supertasters
Olfaction
Definitions
Olfactory receptor cells
Olfactory bulbs

32. Smell, Taste, and Flavor
Smell and taste act as two components of a single system, known as flavor.
Scent and taste pathways converge in the cerebral cortex.
Both tastes and odors prompt strong emotional responses.
Variations in nutritional state affects:
One’s experience of taste and flavor.
One’s motivation to eat particular foods.

33. Figure: The Olfactory System

34. Olfactory System Unique relationship between smell and memory.
Species variability in sensitivity to odor and dependency on smell for survival.
E.g., humans have about 9 million olfactory neurons while dogs have 225 million.
Many species have an accessory olfactory system that detects pheromones.

35. Somesthetic Senses Touch, Pressure, Temperature
Types of sensory receptors
Visceral pain, somatic pain
Congenital analgesia
Congenital insensitivity to pain with anhidrosis
Phantom limb
Pain Gate Control Theory

36. Kinesthetic Sense/ Vestibular Sense
Otolith organs
Semicircular canals
Motion sickness

37. ABC’s of perception The ABC’s of Perception
Size, Shape, and Brightness
Gestalt Principles
Figure-ground
Proximity
Similarity
Closure
Continuity
contiguity

38. Figure 3.20: Gestalt Principles of Perceptual Grouping

39. Depth Perceptions Monocular Cues Linear perspective Relative size
Overlap
Aerial perspective
Texture gradient
Motion parallax
accommodation

40. Linear perspective

41. Relative Size

42. Overlap

43. Aerial Perspective

44. Texture gradient

45. Depth Perception
Binocular Cues
Convergence
Binocular Disparity

46. Perceptual Illusions Hermann Grid Muller-Lyer Illusion
The Moon Illusion
Illusions of motion

47. Hermann Grid

48. Muller- Lyer

49. Other factors that Influence perception
Perceptual sets
Top down processing
Bottom up processing

50. Figure 3.18: Misperceiving Reality
Which Line Is Longer?
From Gardner "Optical Illusions from Figures that are Undecidable to Hot Dogs That Float, Scientific American, 222, 124, 127 Reprinted with permission

51. Figure: Reversible Images
Return

52. Synesthsia
Disorder in which the signals from the various sensory organs are processed in the wrong cortical areas resulting in the sense information being interpreted as more than one sensation.