Distinguishing Between Long-Term Memory and Short-Term Memory • 153participants to study the list as it was being presented by repeating the words out
loud during the 5-second intervals between words. They were not told which words
to repeat—just that they should keep repeating words during the 5-second intervals
between words. The dashed curve, which indicates how many times each word was
repeated, bears a striking resemblance to the fi rst half of the serial position curve.
Words presented early in the list were rehearsed more, and they were more likely to
be remembered later. This result supports the idea that the primacy effect is related
to the longer rehearsal time available for the earlier words on the list.
Superior memory for stimuli presented at the end of a sequence is called the recency
effect. One possible explanation for the better memory for words at the end of the list is
that the most recently presented words are still in STM. To test this idea, Murray Glanzer
and Anita Cunitz (1966) fi rst derived a serial position curve in the usual way (red curve
in ● Figure 6.5). Then, in another experiment, they measured the curve after having their
participants count backward for 30 seconds right after hearing the last word of the list.
This counting prevented rehearsal and allowed time for information to be lost from STM.
The result, shown in the blue dashed curve in Figure 6.5, was what we would predict: The
delay caused by the counting eliminated the recency effect. Glanzer and Cunitz therefore
concluded that the recency effect is due to storage of recently presented items in STM.CODING IN LONG-TERM MEMORY
We can also distinguish between STM and LTM by comparing the way information
is coded by the two systems. In Chapter 5 we saw that auditory, visual, and semantic
coding can occur for STM (with auditory and visual coding being the most prominent).
LTM can also involve each of these types of coding. For example, you use visual coding
in LTM when you recognize someone based on his or her appearance, auditory cod-
ing when you recognize a person based on the sound of his or her voice, and semantic
coding when you remember the general gist or meaning of something that happened
in the past.● (^) FIGURE 6.5 Result of Glanzer and Cunitz’s (1966) experiment. The serial position
curve shows a normal recency eff ect when the memory test is immediate (solid red line),
but no recency eff ect if the memory test is delayed for 30 seconds (dashed blue line).
(Source: M. Glanzer & A. R. Cunitz, “Two Storage Mechanisms in Free Recall,” Journal of Verbal learning and
Verbal Behavior, 5, Figures 1 & 2, 351–360. Copyright © 1966 Elsevier Ltd. Republished with permission.)
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Serial position
Evidence that recency effect is due to STM
0
30
50
70
90
Percent correct
No delay
30-sec delay eliminates
recency effect
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