Experimental Psychology
心理学院
范炤
华中师范大学心理学课程
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Serial location effect:
A term coined by Hermann Ebbinghaus through studies he performed on himself,
refers to the finding that recall accuracy varies as a function of an item's position
within a study list. When asked to recall a list of items in any order (free recall),
people tend to begin recall with the end of the list, recalling those items best (the
recency effect). Among earlier list items, the first few items are recalled more
frequently than the middle items (the primacy effect).
Serial location effect:
One suggested reason for the primacy effect is that the initial items presented are
most effectively stored in long-term memory because of the greater amount of
processing devoted to them. (The first list item can be rehearsed by itself; the
second must be rehearsed along with the first, the third along with the first and
second, and so on.) The primacy effect is reduced when items are presented
quickly and is enhanced when presented slowly (factors that reduce and enhance
processing of each item and thus permanent storage). Longer presentation lists
have been found to reduce the primacy effect.
Serial location effect:
Overt-Rehearsal was a technique that was meant to test participants' rehearsal
patterns. In an experiment using this technique, participants were asked to recite
out loud the items that come to mind. In this way, the experimenter was able to
see that participants would repeat earlier items more than items in the middle of the
list, thus rehearsing them more frequently and having a better recall of the prime
items than the middle items later on.
In addition to rehearsing earlier items more than later items, participants were
rehearsing earlier items later on in the list. In this way, earlier items were closer
to the test period by rehearsal and could be partially explained by the recency effect.
Serial location effect:
One theorized reason for the recency effect is that these items are still present in
working memory when recall is solicited. Items that benefit from neither (the middle
items) are recalled most poorly. An additional explanation for the recency effect is
related to temporal context: if tested immediately after rehearsal, the current
temporal context can serve as a retrieval cue, which would predict more recent
items to have a higher likelihood of recall than items earlier in the list. The recency
effect is reduced when an interfering task is given. Intervening tasks involve
working memory, as the distractor activity, if exceeding 15 to 30 seconds in
duration, can cancel out the recency effect. Additionally, if recall comes
immediately after test, the recency effect is consistent regardless of the length of
the studied list, or presentation rate.
Serial location effect:
Two traditional classes of theories explain the recency effect.
Dual Store Models
These models postulate that later study list items are retrieved from a highly
accessible short-term buffer, i.e. the short-term store (STS). This allows
items that are recently studied to have an advantage over those that were
studied earlier (have to be retrieved with greater effort from long-term
memory store (LTS)).
An important prediction of such models is that the presentation of a
distractor, for example solving arithmetic problems for 10-30 seconds,
during the retention period (the time between list presentation and test)
attenuates such the recency effect. Since the STS has limited capacity,
the distractor displaces later study list items from the STS so that at
test, these items can only be retrieved from the LTS, and have lost their
earlier advantage of being more easily retrieved from the short-term buffer.
As such, dual-store models successfully account for both the recency effect
in immediate recall tasks, and the attenuation of such an effect in the
delayed free recall task.
Serial location effect:
Two traditional classes of theories explain the recency effect.
Single Store Models
According to single-store theories, a single mechanism is responsible
for serial position effects.
A first type of model is based on relative temporal distinctiveness, in
which the time lag between test and the study of each list item
determines the relative competitiveness of an item’s memory
trace at retrieval. In this model, end-of-list items are thought to be
more distinct, and hence more easily retrieved.
Another type of model is based on contextual variability, which
postulates that retrieval of items from memory is cued not only based
on one’s mental representation of the study item itself, but also of the
study context. Since context varies and increasingly changes with
time, on an immediate free-recall test, when memory items compete
for retrieval, more recently studied items will have more similar
encoding contexts to the test context, and are more likely to be
recalled.
系列位置效应:
实验目的：检验对汉字识记和保持中的系列位置作用，学习绘制系列位置曲线。
方法与程序：
本实验可以研究单字学习中的系列位置效应。共100个汉字，从低频到高频
均有，分为五组，每组20个。从第一组到第五组，每组汉字笔画逐渐增多。
实验分4种情况，即1秒立即回忆，2秒立即回忆，1秒延迟回忆，2秒延迟
回忆。1秒和2秒是指识记时每个汉字的呈现时间；立即与延迟是指识记完一组
后，是立即自由回忆还是进行一会儿倒减3分心干扰后再回忆，可选择其中一种。
被试学完每一组汉字后，按要求回忆，输入到对应的输入框中。
实验时一共要学5组，学完之后，屏幕上将给出系列位置曲线。
系列位置效应:
结果与讨论：
详细结果中，列出了学习时字表的顺序、被试的输入结果。
把统计结果填入下表：(系列位置效应实验结果)
位置 被试 1
1
2
┇
ｎ
2
3
…
20
实验情况
系列位置效应:
名词解释：
系列位置效应：识记一系列项目时，项目在系列中的位置对记忆效果有影响，
称为系列位置效应。系列位置效应表现为，在自由回忆时，系列的开始部分和
末尾部分的项目的记忆效果好，而中间部分项目的记忆效果差。
系列位置曲线：根据系列位置效应的实验结果，以识记量为纵坐标，以项目所
在位置为横坐标，绘出的曲线就是系列位置曲线。
首因效应：在系列位置效应中，系列开始部分的项目的记忆效果优于中间部分，
这种现象称为首因效应。
近因效应：在系列位置效应中，系列末尾部分的项目的记忆效果优于中间部分，
这种现象称为近因效应。一般认为，近因效应证实了短时记忆的存在。
短时记忆：短时记忆是指信息一次呈现后，保持时间在1分钟之内的记忆。短时
记忆是操作性的、正在工作的、活动着的记忆。
长时记忆：长时记忆是指学习的材料，经过复习或精细复述后，在头脑中长久
保持的记忆。长时记忆中的信息保存时间在1分钟以上，可以保持数年乃至终生，
是一种长久性的存储。长时记忆的容量是无限的。