1. 6
Sensation and Perception

2. Our Sensational Sensations LO6
Our Sensational Sensations LO6.1 Distinguish between the basic process of sensation and perception, and note where each activity occurs.
Sensation
The detection, by sense organs, of physical energy emitted or reflected by physical objects.
Perception
The process by which the brain organizes and interprets sensory information.

3. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.1 Distinguish between the basic process of sensation and perception, and note where each activity occurs.
Ambiguous figure
The colored surface can be either the outside front surface or the inside back surface.
But not both simultaneously
The brain can interpret the ambiguous cues in two different ways.

4. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.3 Differentiate between absolute thresholds, difference thresholds, and signal detection.
Absolute threshold
The smallest quantity of physical energy that can be reliably detected by an observer
Absolute is a little misleading; borderline signals detected on occasion.

5. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.3 Differentiate between absolute thresholds, difference thresholds, and signal detection.
Absolute thresholds
Vision
A single candle flame from 30 miles on a clear night
Taste
One teaspoon of sugar in 2 gallons of water
Smell
One drop of perfume in a 3-room apartment
Touch
The wing of a bee on the cheek, dropped from 1 cm

6. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.3 Differentiate between absolute thresholds, difference thresholds, and signal detection.

7. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.3 Differentiate between absolute thresholds, difference thresholds, and signal detection.
Difference threshold
The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared.
Also called the just noticeable difference (jnd)

8. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.3 Differentiate between absolute thresholds, difference thresholds, and signal detection.
Signal-detection theory
A psychophysical theory that divides the detection of a sensory signal into a sensory process and a decision process.

9. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.4 Discuss why the principle of sensory adaptation helps us understand how the human perceptual system works.
Sensory adaptation
The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious.
Prevents us from having to continuously respond to unimportant information
Sensory deprivation
The absence of normal levels of sensory stimulation.

10. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.5 Describe how selective attention and inattentional blindness are related.
Sensory overload
The overstimulation of the senses
Can lead to fatigue and mental confusion
Selective attention
The focusing of attention on selected aspects of the environment and the blocking out of others.

11. Our Sensational Sensations, cont’ LO6
Our Sensational Sensations, cont’ LO6.5 Describe how selective attention and inattentional blindness are related.
Intentional blindness
Failure to consciously perceive something you are looking at because you are not attending to it.
One of the hazards of selective attention

12. Vision LO6.6 Describe the three psychological dimensions of vision, and relate them to the three physical properties of light that produce them.
Hue: Dimension of visual experience specified by color names and related to the wavelength of light.
Brightness: Lightness or luminance; the dimension of visual experience related to the amount (intensity) of light emitted from or reflected by an object.
Saturation: Vividness or purity of color; the dimension of visual experience related to the complexity of light waves.

13. Vision, cont’ LO6.6 Describe the three psychological dimensions of vision, and relate them to the three physical properties of light that produce them.
What we see

14. Vision, cont’ LO6.7 Sketch the major structures of the human eye, and briefly describe the functions of each component.
An eye on the world
Cornea: Protects the eye and bends incoming light rays toward a lens.
Lens: Becomes more or less curved to focus light on objects.
Iris: Gives eye its color.
Pupil: Round opening of the eye.

15. Vision, cont’ LO6.8 Discuss the number, arrangement, and functions of rods and cones.
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.

16. Vision, cont’ LO6.9 Outline the proper order of bipolar neurons, optic nerve, photoreceptor cells, and ganglion cells in the path of visual information traveling to the brain.
Structures of the retina

17. Vision, cont’ LO6.10 Summarize the evidence indicating that the visual system is not simply a “camera.”
Why the visual system is not a camera
Neurons in the visual system actively guild up a picture of the world by detecting its meaningful features.
Feature detector
Cells in the visual cortex that are sensitive to specific features of the environment.

18. Vision, cont’ LO6.11 Compare the strengths and weaknesses of the trichromatic and opponent-process theories of color vision.
Trichromatic theory
Known as the Young-Helmholtz theory, applies to the first level of processing, which occurs in the retina of the eye.
Red, blue, and green
All other colors derived by combination

19. Vision, cont’ LO6.11 Compare the strengths and weaknesses of the trichromatic and opponent-process theories of color vision.
Opponent-process theory
A theory of color perception that 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.

20. Vision, cont’ LO6.12 List four Gestalt principles of perception, and give an example of each.
A-level
B-level
C-level
D-Level
E-Level

21. Vision, cont’ LO6.12 List four Gestalt principles of perception, and give an example of each.
A-level
B-level
C-level
D-Level
E-Level

22. Vision, cont’ LO6.12 List four Gestalt principles of perception, and give an example of each.
Form perception
Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns.

23. Vision, cont’ LO6.12 List four Gestalt principles of perception, and give an example of each.
Proximity
Things that are near each other tend to be grouped together.
Closure
The brain tends to fill in gaps to perceive complete forms.

24. Vision, cont’ LO6.12 List four Gestalt principles of perception, and give an example of each.
Similarity
Things that are alike in some way are perceived as belonging together.
Continuity
Seeing continuity in lines that could be interpreted as either continuous or abruptly shifting in direction.

25. Vision, cont’ LO6.13 List the factors that contribute to depth and distance perception.
Binocular cues
Visual cues to depth or distance requiring two 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.

26. Vision, cont’ LO6.13 List the factors that contribute to depth and distance perception.
Monocular cues
Visual cues to depth or distance, which can be used by one eye alone.
Interposition
When an object is interposed between the viewer and a second object, partly blocking the view of the second object, the first object is perceived as being closer.
Linear perspective
When two lines known to be parallel appear to be coming together or converging (say, railroad tracks), they imply the existence of depth.

27. Vision, cont’ LO6.14 Describe five types of visual constancies, and discuss how each contributes to the process of visual perception.
Visual constancies
The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce.
Size constancy
Shape constancy
Location constancy
Brightness constancy
Color constancy

28. Vision, cont’ LO6.15 Explain how visual illusions help us understand the normal processes of visual perception.
The Müller-Lyer illusion

29. Vision, cont’ LO6.15 Explain how visual illusions help us understand the normal processes of visual perception.
Color in context
The way you perceive a color depends on the surrounding colors.

30. Vision, cont’ LO6.15 Explain how visual illusions help us understand the normal processes of visual perception.
Fooling the eye

31. Hearing LO6.16 Describe the three psychological dimensions of hearing, and relate them to the three physical properties of sound that produce them.
What we hear
Loudness
The dimension of auditory experience related to the intensity of a pressure wave.
Pitch
The dimension of auditory experience related to the frequency of a pressure wave.
Timbre
The dimension of auditory experience related to the complexity of a pressure wave.

32. Hearing, cont’ LO6.17 Sketch the major structures of the human ear, and briefly describe the functions of each component.
An ear on the world

33. Hearing, cont’ LO6.18 List five Gestalt principles of perception that apply to constructing the auditory world, and give an example of each.
Auditory localization
Sounds from different directions are not identical as they arrive at left and right ears.
Loudness
Timing
Phase
The brain calculates a sound’s location by using these differences.

34. Hearing, cont’ LO6.18 List five Gestalt principles of perception that apply to constructing the auditory world, and give an example of each.
Gestalt principles
Figure: In class, your instructor’s voice.
Ground: Distant cheers from the athletic field.
Proximity: In music, notes in a melody tell you which notes go together.
Continuity: In music, helps you follow two melodies.
Similarity: Helps you pick out soprano voices in a choir.
Closure: Helps you understand a caller’s words when there is interference.

35. Other Senses LO6.19 Sketch the major structures of the human tongue, and briefly describe the functions of each component.
Papillae
Knoblike elevations on the tongue,
containing the taste buds.
Taste buds
Nests of taste
receptor cells.

36. Other Senses, cont’ LO6.20 List the five basic tastes perceived by humans.
Salty, sour, bitter, sweet, and umami
Different people have different tastes based on:
Genetics
Culture
Learning
Illnesses
Food attractiveness

37. Other Senses, cont’ LO6.20 List the five basic tastes perceived by humans.
Taste test

38. Other Senses, cont’ LO6.21 Sketch the basic pathway from smell receptors to the cerebral cortex.
Smell: The sense of scents
Airborne chemical molecules enter the nose and circulate through the nasal cavity.
Vapors can also enter through the mouth and pass into the nasal cavity.
Receptors on the roof of the nasal cavity detect these molecules.

39. Other Senses, cont’ LO6.22 List the four basic skin senses that humans perceive.
Senses of the skin
The basic skin senses include touch (or pressure), warmth, cold, and pain.
Within these four types are variations such as itch, tickle, and painful burning.

40. Other Senses, cont’ LO6.23 Describe the principles of gate-control theory.
Gate-control theory of pain
Experience of pain depends in part on whether the pain gets past a neurological “gate” in the spinal cord.

41. Other Senses, cont’ LO6.24 Define phantom pain, and describe a novel way of treating it.
Expectations and pain

42. Other Senses, cont’ LO6.25 Discuss the two senses that allow us to monitor our internal environment.
The environment within
Kinesthesis
The sense of body position and movement of body parts.
Equilibrium
The sense of balance.
Semicircular canals
Sense organs in the inner ear that contribute to equilibrium by responding to rotation of the head.

43. Perceptual Powers LO6.26 Summarize the evidence suggesting that our perceptual powers are both inborn and dependent on experience.
Perceptual powers: Origins and influences
Glass surface, with checkerboard underneath at different heights
Visual illusion of a cliff
The baby cannot fall
Mom stands across the gap.
Babies show increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl.

44. Perceptual Powers LO6.26 Summarize the evidence suggesting that our perceptual powers are both inborn and dependent on experience.
Critical period
If infants miss out on experiences during a crucial period of time, perception will be impaired.
When adults who have been blind since birth have vision restored, they may not see well.
Other senses such as hearing may be influenced similarly.

45. Perceptual Powers, cont’ LO6
Perceptual Powers, cont’ LO6.27 Discuss four psychological factors that influence how we perceive the world.
Psychological and cultural influences
We are more likely to perceive something when we need it.
What we believe can affect what we perceive.
Emotions, such as fear, can influence perceptions of sensory information.
Expectations based on previous experiences can influence perception.
Perceptual set: A habitual way of perceiving, based on expectations
All are influenced by culture.

46. Perception without Awareness LO6
Perception without Awareness LO6.28 Summarize the evidence both for and against subliminal perception.
Perception vs. persuasion
Although subliminal priming can influence judgments and preferences, research doesn’t support its success in major levels of persuasion.

47. Perception without Awareness LO6
Perception without Awareness LO6.28 Summarize the evidence both for and against subliminal perception.
Extrasensory perception
ESP
The ability to perceive something without ordinary sensory information.
Has not been scientifically demonstrated