1. Bell Work
What is the difference between sensation and perception?

2. Objective
Students will differentiate between S&P.

3. What do you see? What Do you Know?
Reality is merely an illusion, although a very persistent one.
Albert Einstein
kids.niehs.nih.gov/illusion/illusions.htm

4. Bell Work
What are the five most well-known senses?

5. Senses Sight Hearing Touch Smell Taste Vestibular (balance)
Temperature
Kinesthetic
Pain

6. What is the difference between Sensation and Perception?
Sensation furnishes the raw material of sensory experience, while perception provides the finished product
Sensation is the sensory process that
detects visual, auditory, and other sensory stimuli
and transmits them to the brain.
Perception is the brain process that:
actively organizes sensory information
and interprets sensory information

7. Perception: The Basic Process
Physical presence of something
Sensory detection of it
(eyes, ears, nose, tongue, skin)
Transduction of physical energy to a signal that the brain can use (neurotransmission)
Analysis of attributes (size, edges)
Comparison of object to known objects in memory
Attention (or not)
Recognition of object and its location
Action
Memory

9. Bottom-up Processing
Analysis of the stimulus begins with the sense receptors and works up to the level of the brain and mind.
Letter “A” is really a black blotch broken down into features by the brain that we perceive as an “A.”

10. THE CHT Top-Down Processing
Information processing guided by higher-level mental processes as we construct perceptions, drawing on our experience and expectations.
THE CHT

11. Bottom-Up vs. Top-Down
When an interpretation emerges from the data, this is called data-driven or bottom-up processing. You want the interpretation of a scene to be determined mostly by information from the senses, not by your expectations.
In general, top-down processing—information processing based on previous knowledge or schemata—allows us to make inferences: to "perceive" or "know" more than is contained in the data.

12. Selective Attention Cocktail party effect:
filtering out all other noises and focusing on one conversation.
When filtering out all
other noises, the phenomenon of attention being drawn by the sound of your name, or other interesting sounds.

13. Selective Attention Selective Attention and Accidents
Cell phone use and car accidents

14. Selective Attention Selective Inattention
Inattentional blindness is a psychological lack of attention and is not associated with any vision defects or deficits. It may be further defined as the event in which an individual fails to recognize an unexpected stimulus that is in plain sight.

15. In most groups, 50% of the subjects did not report seeing the gorilla
In most groups, 50% of the subjects did not report seeing the gorilla. The failure to perceive the anomalies is attributed to the failure to attend to it while engaged in the difficult task of counting the number of passes of the ball. These results indicate that the relationship between what is in one's visual field and perception is based much more on attention than was previously thought.[

16. Although it was found that 50% of the test subjects demonstrated change blindness to the introduction of the gorilla, it is difficult to find published information on what percentage of study participants were able to accurately count the passes.
The basic study was re-used on British television as a PSA designed to point out the potential dangers to cyclists caused by inattentional blindness in motorists.

17. Selective Attention Selective Inattention
Change blindness
Change deafness
Choice blindness

18. Stimuli we are sensitive to
Smell and taste molecules in air and saliva
Feel temperature on skin
Hear sound pressure waves
See electromagnetic waves
Feel pressure on skin
Sense acceleration of one’s head

19. The physical world and the psychological world
Physical variables can be measured
Psychological variables can only be reported
Sound pressure level   Loudness
Frequency   Pitch
Luminosity   Brightness
Temperature ?
Smell
Skin pressure
In measuring 1 oz + 1oz + 1 oz + 1 oz = 4 oz, but if it doesn’t take up space you have a red swatch & a pink one, can we say that red is 4 pinks?

20. Mapping between Worlds
A physical variable X may be lawfully related to a psychological variable Y
We can explore the relationship between
Physical properties
Collection of that data
Subjective Experience
Psychophysics

21. Basic Questions Detection Recognition Discrimination Scaling
What is the minimum intensity we can detect ?
Recognition
What is the signal we detect ?
Discrimination
How different must 2 stimuli be before they no longer appear the same ?
Detection and Recognition is “real”, where discrimination is a measure of rate of change, scale is an evaluation
Scaling
What is the relationship between stimulus intensity & sensation & perception ?

22. Detection Absolute Threshold Just Notable Difference – JND
The minimum amount of energy in a sensory stimulus that is detected 50% of the time
So if the stimulus is subliminal what is the detection rate?
Just Notable Difference – JND
The smallest change in sensation that a person is able to detect 50% of the time.
Subliminal stimulus is one that is detected only up to 49% of the time
“Lifted the sensation… over the threshold of consciousness” Fetchner
This produces a …
Difference Threshold
The amount of stimulus needed detect a difference 50 % Of the time

23. Absolute Thresholds in our Senses
1. Vision, a candle flame 30 mile(s) away on a clear night
2. Hearing, a watch ticking 20 feet away
3. Taste, 1 teaspoon of sugar dissolved in 2 gallons of water
4. Smell, a single drop of perfume in a three room house .
1. vision, a candle flame 30 miles away on a clear night
2. hearing, a watch ticking 20 feet away
3. taste, 1 teaspoon of sugar dissolved in 2 gallons of water
4. smell, a single drop of perfume in a three-room house
5. touch, a bee’s wing falling a distance of 1 centimeter onto the cheek.
5. Touch, a bee’s wing falling a distance of 1 cm onto your cheek.

24. Difference Threshold Weber’s Law Just Noticeable Difference (JND)
The amount of stimulus needed to detect a difference 50 % of the time
Just Noticeable Difference (JND)
Weber’s Law
As the stimulus increases, the JND increases at a constant rate.

25. Fetchner’s Law As the physical intensity of a Stimulus increases, our
Perception increases rapidly at
First then more slowly
Doubling a light’s intensity doesn’t double it’s perceived Brightness.
Fechner's scales -Richter scale as the Richter scale goes up by equal units the severity of an earthquake goes up in a ratio 1 unit = 31 times of energy
Weber’s law says the JND is a constant ratio of the physical stimulus
Fechner’s law says that the subjective magnitude of the JND is constant, or more generally, that we can use the JND as a unit of measurement of subjective intensity
Weber’s Law

26. Scaling: Steven’s Power Law
Perceived intensity = physical intensity X constant power for each type of judgment
For instance, to perceive a light as twice as bright, its actual intensity has to be increased between and 8 and 9 times
Likewise, if an electric shock is doubled in intensity, we perceive it as being about 10 times more intense
Sensory adaptation to repetitive or unchanging stimuli
Survival and economy: it is more important to detect new stimuli (which may signal danger) than constant stimuli

27. Signal Detection Theory
Person's Response
Stimulus detected
Stimulus undetected
Stimulus present
Hit
Miss
Stimulus absent
False alarm
Correct rejection
Reality
Detection of a stimulus also depends on psychological factors, such as personality, motivation, and past experiences.

28. With up to two partners on one piece of paper
Stimulus detected
Stimulus undetected
Stimulus present
Hit
Miss
Stimulus absent
False alarm
Correct rejection
With up to two partners on one piece of paper
1A A stream has just been stocked w/ fish. A fisherman who has been unsuccessful at this location in the past only tries for 5 minutes
1B he then travels to a nearby pond that has no fish in it. A minute after throwing in his line snags what he thinks is a big fish. It is actually a boot.
2A.A baby sitter detects frightening noises after watching a scary movie. The noise is the trees rustling in the wind
2B The next day she is at soccer practice. She does not detect the trees nearby making the same noise.
3.You design the scenarios: A young person goes to the local dance club in hopes of meeting someone nice to date.

29. Knowledge
In the mind
Recognition
Perception
subjective
Processing
Action
objective
Environmental
stimulus
Transduction
Stimulus on
receptors
Attended
stimulus
In the
world
In the head

30. Bell Work
What is the difference between a two-dimensional figure and a three-dimensional figure?

31. Objective
After watching Bob Ross paint his “Happy Little Trees,” students will identify and analyze the use of depth cues.

32. Size Constancy
Size constancy refers to the fact that our perceptions of the size of objects are relatively constant despite the fact that the size of objects on the retina vary greatly with distance. 

33. Take a look at the photograph and see if all the people in it all look reasonably the same size.

35. Ponzo Illusion

36. Depth Cues There is no actual depth in the artwork.
Disparity arises from the fact that our two eyes have a slightly different view of the world. To allow you to see disparity requires either real depth or two images developed as if from different positions like our eyes.
Monocular depth cues: Light and Shadow

37. The Cone

38. Interposition is the partial blocking of a more distant object by a nearer object.
Check the small figure with the word interposition. There are two rectangles with the farther rectangle, lower and to the right, partially obscured by the nearer one, right?
Well, actually both rectangles are at the same distance (the distance of the screen from your eyes). It is the interposition, overlap, that causes the sense of depth to arise. Usually the impression of depth caused by interposition alone is not very strong.

39. Relative Height
This cue can lead to a powerful sense of depth as seen in this landscape.
As there are not any objects, nor any interposition, nor any real strong texture, the primary cues to depth being used in this picture is relative height.
The general rule is that the closer to the level of the horizon, the farther away the object appears.

40. Relative Size
The more distant an object is, the smaller the image of that object will be on your retina, the back of the eye where we really begin to "see.”
The closer boat is painted much larger than the other. Even the two paddles near each other show the use of relative size.
The boater in the background does not look abnormal in any way. Despite being painted smaller, the person does not look like a midget.

41. Texture Gradient
The farther away the object is, the less textured it is and the less detailed it is.

42. Look at the large center bump. Is it raised or indented?
Shadow
Look at the large center bump. Is it raised or indented?

43. Bob Ross

44. How does Bob Ross use the following to create the perception of depth?
Interposition
Relative Height
Relative Size
Texture Gradient
Shadow