130 • CHAPTER 5 Short-Term and Working Memory
- Describe sensory memory and Sperling’s experiment in which he briefl y fl ashed
an array of letters to measure the capacity and duration of sensory memory. - Is memory lost from STM by decay or by interference? Be sure you understand
the Peterson and Peterson experiment and Keppel and Underwood’s interpreta-
tion of it. What is the time span of STM? - What is the capacity of STM, and how is it infl uenced by chunking?
- Describe evidence supporting the following types of coding in STM: auditory
(Conrad letter memory experiment); visual (Della Sala matrix experiment); and
semantic coding (Wickens fruits and professions experiment).
Working Memory
The modal model stimulated a great deal of research on short-term memory. But as
research on STM progressed, it became apparent that the concept of STM as presented
in the modal model was too narrow to explain many research fi ndings. The problem
was that STM was described mainly as a short-term storage mechanism. But as we saw
in our description of Rachel ordering a pizza, memorizing a phone number involves
transferring the number from STM into LTM, and remembering it then involves trans-
ferring it from LTM back into STM. Thus, the role of STM extends beyond storage. It
is also involved in the transfer of information to and from LTM. We can take this idea
further by listening in on Rachel’s conversation with the pizza shop:
RACHEL: “I’d like to order a large pizza with broccoli and mushrooms.”
REPLY: “I’m sorry, but we’re out of mushrooms. Would you like to substitute
spinach instead?
Rachel was able to understand the pizza shop’s reply by holding the fi rst sentence,
“I’m sorry, but we’re out of mushrooms,” in her memory while listening to the second
sentence and then making the connection between the two. If she had remembered only● FIGURE 5.12 Results of Wickens et al.’s (1976) proactive inhibition experiment. (a) Fruit
group, showing reduced performance on trials 2, 3, and 4 caused at least partially by proactive
interference (indicated by blue points). (b) Professions group, showing reduced performance
on trials 2 and 3 but improved performance on trial 4. The increase in performance on trial
4 represents a release from proactive interference caused by the change of category from
professions to fruits. (Source: Based on D. D. Wickens, R. E. Dalezman, & F. T. Eggemeier, “Multiple Encoding of Word Attributes in
Memory,” Memory & Cognition, 4, 307–310, 1976.)020406080100Percent recalled1234FFFFTrialProactive
interference020406080100Percent recalled1234PPPFTrialRelease
from PIPI(a) Fruit group (b) Professions group● FIGURE 5.13 Answer matrix for
the visual recall test. Put a check in
each square that was darkened in
the pattern you just looked at.Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.