Assignment 1. QOTW: How do scientists measure perception?
1A Find and report on two different web sites that tell you something about how vision scientists measure visual perception in humans. Your final report should be no more than 1 page of single-spaced text. In each half page, list the URL (www site) and then, in your own words, tell the reader what the highlights of this website are.
Assignment 2. QOTW: What are the units of the mind? How do they work?
2A Imagine that you are an engineer exploring the possible benefits of mutual inhibition among a set of light sensitive units. One stimulus you might begin with in your exploration is light consisting of two different levels (Stimulus 1). Call the two levels "dark" and "bright", for simplicity. This is really nothing more than an "edge" of light. Now imagine that the dark light is said to be worth 10 units and the bright light is worth 100 units. The diagram below may help you in your thinking. Pretend that the diagram extends beyond A and D at the same input levels shown. A second stimulus you can work with is Stimulus 2 below.
bright ----------------------- Stimulus 1 dark -------------------- Input to neurons 10 10 100 100 Neurons A B C D Output of neurons ?? ?? ?? ?? bright ----------- Stimulus 2 ----------- ----------- dark ----------- ------ Input to neurons 10 50 100 50 10 Neurons A B C D E Output of neurons ?? ?? ?? ?? ??
Scenario 1. The neurons in
this system merely record the level of light that they are exposed to. They
each work independently of the others.
1. What will be the output of neurons for Scenario 1? (For neurons A-D in
Stimulus 1 and neurons A-E in Stimulus 2)
Scenario 2. The neurons in
this system inhibit their nearest neighbours at a level proportional to their
input level of activation. Lets say the level of inhibition is 10%. Then neuron
B inhibits neurons A and C each by 1 unit, since its input level is 10 units
(10% of 10 is 1). Neuron C, on the other hand, inhibits neurons B and D by 10
units (10% of 100 is 10).
1. What will be the output of neurons in Scenario 2? (For neurons A-D in
Stimulus 1 and neurons A-E in Stimulus 2)
2. What effect will this pattern (Scenario 2) have on the registration of the
edge of light?
3. Which scenario is more like the cone receptors of the human retina? Which is
more like the rod receptors?
Assignment 3. QOTW:
How is time important to perception?
3A Begin with three (3) pictures of line drawings of easily identifiable common
objects (animals, plants, artifacts or people). Each object should occupy about
1/4 to 1/3 of a page. Take these from children's coloring books, magazines,
photocopy them from books, or make your own line drawings of objects (if you
can). Put them on separate pages. Make up a viewing screen, consisting of an
opaque piece of paper (nothing should be visible through the paper) with a
small round hole (1/2 inch or 1-2 cm). Record your observations of people
trying to identify the objects under the following conditions:
a. Very rapid back-and-forth movement of the viewing screen over the pictures
versus very slow movement.
b. Movement of the viewing screen under experimenter control versus
under observer control.
c. Systematic movements of the viewing screen around the outside contour of the
picture versus random movements all over the picture at the same speed.
Questions to be answered:
1. Why does very rapid movement of the viewing screen make object
identification quite easy, even though only a 1-2 cm portion is ever visible at
the same time?
2. How does the person in control of the movement influence the ease of
perception? Why?
3. Which is easier: systematic or random movements? Why?
3B Alternate Assignment:
Remember the simple moving cartoons you used to draw as a child? Take two small pieces of paper and place one on top of one another. Staple or tape them together at the top. Draw the same picture in the same place on each page, with the exception of a single difference that corresponds to the moving part. This part should be in a different location on each page. The top piece of paper is now rolled around a pencil and then the pencil is moved back and forth to reveal the top page and the bottom page in alternating fashion.
Make
up these kinds of animated cartoons to illustrate the following phenomenon:
a. simple apparent motion in the picture between two identical shapes (e.g.,
circles)
b. the correspondence problem is solved automatically by the brain when the top
page contains one shape and the bottom page contains two shapes in different
places
c. plastic or "morphing" transformations can occur between two
different shapes
Questions to be answered:
1. How does the speed of the movie influence the findings for a, b, c?
2. How are these principles of apparent motion important in viewing real
movies?
Assignment 4. QOTW:
What determines the color of an object?
4A Construct a picture consisting of many differently-colored rectangles that
touch and overlap one another. In the middle of this place a white square patch
of paper. Pieces of solid colored construction paper can be cut and pasted
quite easily to create this kind of "Mondrian" display. In addition
to this color rectangle display, two more pieces of apparatus are required. One
is a see-through piece of colored cellophane or transparent colored plastic
that can be placed over the display (sunglasses will do). The other is a black
piece of paper (called the mask) with a cutout corresponding to the position
and shape of the white square in the center of the display. This is the
"target" color. Ask subjects to name the color of the target patch
under three conditions (and in this order):
a.
when the display is covered both with the colored transparency and with the
black mask, so that only the target square is visible through the transparency
and the hole in the black mask
b. when the display is covered with the colored transparency, but the black
mask has been removed
c. when the target square is viewed without the transparency in front of
it, but still through the black mask, and
d. when the target square is viewed without the transparency and without
the mask.
Questions
to be answered:
1. What does the color of the target square look like in each of the conditions
a-d? What color names would you use?
2. How does color constancy influence the color that is seen?
Assignment 5. QOTW: Is visual art an illusion? What kind?
5A Find a magazine picture
with rich cues to pictorial depth. This is your background scene. From another
picture, cut out an object that could fit conceptually into the background
scene. Have subjects indicate the perceived size of the object by drawing a
blob on a separate piece of paper that is approximately the identical size of
the object. Do this under two different conditions:
a. when you have placed the object in an extreme "distant" part in
the background scene.
b. when you have placed the object in a "near" foreground location.
Questions:
1. Do subject draw larger circles in condition a or b?
2. How does size constancy influence the apparent size of the object?
5B
Alternate Assignment
Draw vertical versions of the two Mueller-Lyer displays (wings-out and
wings-in) side-by-side on the same page. Displace the wings-in version a little
downward on the page so that the two test lines are not perfectly aligned. This
is stimulus A. Now copy (trace) this picture exactly, but embellish this second
picture with other lines that are consistent with a larger scene containing
perspective. This is stimulus B. Indicate the test lines in both pictures with
a bold line, so that there is no mistake which lines subjects will be asked to
reproduce. Have subjects indicate the perceived lengths of each of the lines by
drawing their own corresponding lines on four separate pieces of paper.
Questions:
1. What are average lengths of the lines drawn by subjects in the four
conditions (i.e., A-wings out, A-wings in, B-wings out, B-wings in)?
2. Are the results for A (wings-in versus wings-out) consistent with the
standard Mueller-Lyer illusion?
3. How does a context of pictorial perspective in B influence the apparent
lengths of the lines?
Assignment 6. QOTW:
What is the basis of self-deception in human thinking?
6A Prepare WRITTEN answers to the following questions from Rama 6-7. Come
prepared to discuss these answers in the tutorial.
1. Why is the condition of neglect, following a stroke, more
likely to occur if the stroke is on the right side of the brain?
2. Give an example of an experiment that has been performed to demonstrate that
visual information from the neglected side of the visual field is nonetheless
being processed by the brain.
3. Describe the phenomenon of mirror agnosia.
4. What is anosognosia?
5. How do Rama and Freud differ in their interpretation of denial in some
stroke patients?
6. Why does Rama think that caloric stimulation eliminates denial temporarily?
Assignment 7. QOTW: Why does perception need attention?
7A Show that you can apply your understanding of visual attention to the design of effective advertising displays. Design two of your own displays (perhaps something like the "Great Waldo Search") to illustrate the difference between parallel (or pop-out) search and serial (or effortful) search. Use background scenes from magazines or of your own design. Use a target object (other than Waldo) that you find interesting. The critical design features are:
a.
the target object must be identical in the two displays
b. the number and location of background objects must be identical in the two
displays; color and shape may vary
c. the target must "pop out" at a naive observer in display one, and
d. the target must require "serial scanning" by a naive observer in
display two.
Questions:
1. What aspects of a visual display makes for difficult visual search?
2. What does this tell us about the brain?
Assignment 8. QOTW:
How many kinds of memory are there?
8A Construct three lists of 20 English words, preferably all common nouns
(e.g., desk, beaver, letter, apple, etc). For each list, make sure that there
are 5 words in each of four different common categories such as furniture,
animals, fruits, stationary supplies, etc. The order of the words should then
be scrambled into a haphazard list of apparently unrelated words. (The easiest
way to do this is write them down on small pieces of paper and remove them from
a bag one at a time.) Administer these lists, one at a time, to a cooperative
participant that is naive to the purpose of the test. Begin each list by
saying, "This is a test of free recall. I will read you a list of 20 words
at a rate of approximately 1 per second. Listen to these words, doing your best
to remember them as well as you can. When I have completed reading the list, I
will give you the opportunity to write down as many of the words as you can
remember. The order in which you write down the remembered words is not
important."
List 1: the standard control condition, with instructions as given above.
List 2: at the end of this list ask the participant to immediately begin subtracting the number 3 from 100. As them to write down the number 100, subtract 3 to write down 97, subtract 3 to write down 94, and so on. After 30 seconds of this nonsense, permit them to perform free recall for the words in the memory list.
List 3: After one attempt at free recall, as in List 1, tell them about the 4 categories used to generate words in the list. Tell them what the categories are, but not any of the actual items, and then see if they can remember any more of the words.
Record the results for each list in the form of a graph, with the "number correct" on the Y-axis and 5 serial positions (words 1-4, 5-8, 9-12, 13-16, 17-20) in the list on the X-axis.
Questions:
1. How does recall accuracy vary with list position for List 1?
2. What does this pattern for List 1 tell you about how short-term memory is
structured?
3. What does the arithmetic interference test do to list accuracy in List 2?
4. What does this mean?
5. How many more words were recalled in List 3 when prompted category recall
was compared with the first free recall?
6. What do the results for List 3 tell you about memory storage versus memory
retrieval?
Assignment 9. What is unique about natural language?
11A What are the rules for the onset of a syllable in English? Construct a Table in which each of 25 rows corresponds to a phoneme (sound unit) in the English language. List the consonantal phonemes in the following order (start with # for none, then p, t, k, b, d, g, m, n, ng, f, th, s, sh, ch, v, z, zh, j, l, r, y, w, hw, h). Each of 25 columns also corresponds to a phoneme in English (start with V for any vowel, then p, t, k, b, d, g, m, n, ng, f, th, s, sh, ch, v, z, zh, j, l, r, y, w, hw, h).
IMPORTANT REMINDER: these letters refer to SOUNDS, not to letters of the alphabet. For example, "b" refers to the first sound made in "ba", not to the letter b. Useful websites:
· English Consonants: http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec1/cons.htm
· English Vowels: http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec1/vowels.htm
· English Phonemes (with sample pronounciations)
· http://www.geocities.com/Athens/Delphi/8940/main.htm
Now fill in the table with an X to indicate: Which of the phonemes in the rows may be followed by which of the phonemes in the columns, in order to begin an English syllable? Place an X in each box in the Table that corresponds to a legal syllable onset in standard English.
Questions:
1. Which are privileged phonemes? By "privileged" we mean that these
phonemes are permitted to be spoken together, in a cluster.
2. Why are only some combinations of phonemes allowed?
3. How is the STRUCTURE of spoken language visible in this chart?
Assignment 10. QOTW: What are some relatively easy questions about consciousness?
10A Do women and men experience the same world differently? An experiment on the experience of space and navigation.
Definitions:
- a landmark-based instruction refers to an episodic memory for an object at a critical
location along a route, the object is defined by its local context.
- a route-based
instruction refers to overall relations between the start and end points of a
route, cues to distance and direction are defined globally, with reference to a
bird's eye view
Provide two different sets of instructions for a new person on campus, so that they can find their way successfully from our classroom in Angus (Buchanan) to my office in the Kenny Building. This person will have no other resources other than their own eyesight and your instructions. In the A set of instructions, primarily provide information regarding relevant landmarks; that is, be sure to minimize the route-based instructions. In the B set of instructions, primarily provide information regarding the route; minimize the landmark-based instructions. Let several people read these instructions and ask them to tell you which is easier to follow. Record the gender of the subject along with their answer. Indicate your own gender identity on the assignment as another source of relevant information.
Questions:
1. Is there a relationship between preferences for one of your two instructions
and subject gender?
2. How does your own gender interact with these findings?
3. What do these findings mean about the way men and women experience the same
physical world?