Winter 99, Exam 1

Psy 5054 ]


Part 1: Multiple Choice. Circle the letter corresponding to the correct answer. Only one answer is correct for each question. (1 point each)

1. McClelland and Rumelhart's (1981) Interactive Activation Model, unlike PANDEMONIUM, assumes that letter recognition is a(n) _____ process.
(a) bottom up
(b) top down
(c) interactive

2. The information in the speech stream associated with most speech sounds (phonemes) changes depending on the context in which the sound is uttered. Thus, the physical properties of the /d/ sounds in the words "dig" and "dug" are different. This is often called the _____ problem.
(a) lack of invariance
(b) underarticulation
(c) visible speech

3. Experiments using functional Magnetic Resonance Imaging (fMRI) have shown that when participants listen to sentences, the flow of blood to both Wernicke's Area and Broca's Area increases as grammatical complexity increases. By the logic of the _____ technique this suggests that both of these areas are involved in processing the grammatical structure of a sentence.
(a) subtraction
(b) additive factors
(c) both a and b

4. A cognitive process that uses up short-term memory capacity is _____.
(a) parallel
(b) controlled
(c) automatic

5. Which of the following symptoms is not normally associated with damage to the right cerebral cortex?
(a) inability to understand reversible sentences
(b) difficulty recognizing and expressing emotion
(c) diminished speech prosody

6. The Wernicke-Lichteim-Geschwind Model of Aphasias is formulated at the level of analysis that Marr referred to as the _____.
(a) computational theory
(b) representation and algorithm
(c) hardware implementation

7. If Rumelhart and McClelland (1982) had found that letters are just as difficult to recognize in unpronounceable non-words that share letter combinations with real words (e.g., "SLNT") as they are in unpronounceable non-words that don't share letter combinations with real words (e.g., "XLQJ"), then _____ would have been falsified.
(a) the whole word model of reading
(b) the Interactive Activation Model
(c) PANDEMONIUM

8. In a(n) _____ writing system each character (or grapheme) represents a different phoneme.
(a) logographic
(b) alphabetic
(c) pictographic

9. McClelland and Rumelhart (1981) found that the difference in activation levels between high- and low-frequency words in their Interactive Activation Model increases over processing cycles when both are
equally consistent with the input. They refer to this as the _____ effect.
(a) gang
(b) rich-get-richer
(c) pseudo-word superiority

10. In a short-term memory experiment, a participant presented with the word "dog" in a to-be-remembered list would be most likely to make a false-positive response (saying "Yes, I saw that." instead of
"No, I didn't see that.") in response to the test word _____.
(a) "cat"
(b) "log"
(c) "puppy"

Part 2: Definitions. In just 1 or 2 sentences, give an operational definition for each of the following concepts. Your definition may come from an experiment you are familiar with or you may make up your own definition (as long as it accurately defines the concept and is operational). (2 points each)

Grading Criteria:

    1 pt. for correctly identifying the concept
    1 pt. for using a procedural definition


11. Reversible versus Nonreversible Sentences

To determine if sentences are reversible or nonreversible I would present them to a group of participants and ask them to judge whether they still make sense when the agent and object are reversed (e.g., "The boy ate the bagel." --> "The bagel ate the boy."). Those for which a majority responded "yes" could then be classified as reversible while those for which a majority
responded "no" could be classified as nonreversible.

12. Word Frequency

I would begin by collecting a very large sample of naturally occurring language such as all the magazines published in the U. S. during 1998. To determine the frequency of a given word, I would then calculate the number of times it occurs (per million words) in my sample.

13. Working Memory Capacity

I would auditorily present participants with groups of 5, 6, 7, etc. randomly selected digit and ask them to repeat them back immediately. I would use the highest number of digit that a participant was correct on at least half the time as a measure of his or her working memory capacity. [Note: This is the standard memory span measure.]

14. The Word Superiority Effect

To demonstrate the Word Superiority Effect, we could ask people to look at a fixation point on a computer screen then name, as quickly as possible, letters that appear in its place. The Word Superiority Effect can then be defined as the difference in letter naming times (the time that elapses between presenting a letter and detecting the naming response) between letters presented
alone (e.g., "O") and letters presented in the context of a word (e.g., "DOG").


15. An Evoked Response Potential (ERP)

To measure Evoked Potentials we could attach electrodes to participants heads and measure changes in electrical conductivity under two conditions: while they are staring at a fixation point and when that fixation point is replaced (very breifly) by some stilulus such as a word. We could then define the ERP as the difference between these two conditions.

Part 3: Short Essay. Answer each of the following questions using no more than half of a page for each. (5 points each)

16. Design a functional neuroimaging experiment which uses the subtraction technique to identify the neural structures involved in identifying printed letters. Do not worry about the details of neuroimaging, just
take it for granted that you can measure changes in cerebral blood flow as the participants in your study engage in the tasks you assign them.

Grading Criteria:

    1 pt. for appropriate experimental task
    1 pt. for appropriate comparison task
    2 pts. for using the difference between the experimental and comparison tasks to identify the neural structures         of interest
    1 pt. for overall coherence of the answer


Example Answer:

To perform this study we would need to monitor cerebral bllod flow during both an experimental task which involves identifying letters and a comparison that involves all the same processes as the experimental task EXCEPT letter identification. For the experimantal task I would ask participants to silently look at all 26 letters formed out of the set of visual features described by McClelland & Rumelhart (1981) in thier article on the Interactive Activation Model. Because letter identification is an automatic task, we know that participants will identify the letters even though they are not explicitly instructed to. For the comparison task I would ask them to silently look at 26 patterns formed by combining the same set of features in novel ways to form non-letters. The number of features in each non-letter would be matched to the number in a different "real" letter. In addition, each feature would be used the same number of times in the non-letters as in the letters. I would then subtract the pattern of cerebral blood flow observed in the comparison task from the pattern observed in the experimental task to find the areas of the brain involved in identifying printed letters.

17. Describe the "100 step maximum" and explain why it is important to the psychology of language.

Grading Criteria:

    2 pts. for correctly describing the 100 step maximum
    2 pts. for explaining its importance
    1 pt. for overall coherence of the answer

Example Answer:


According to the 100 step maximum, the nervous system can enter at most 100 discrete, sequential states during the time required to perform a highly automated recognition task such as reading a letter or word. If we are willing to accept this (Some people aren't!), it provides an important constraint on models of how such processes work. Any model that proposes that more
than 100 discrete, sequential steps are involved in recognition is inconsistent with the 100 step maximum.


Psy 5054 ]

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This page was last updated on 11/09/99.