Theme 3 – Memory Retrieval
Levy & Andereson (2002). Inhibitory processes and the control of memory retrieval.
There is a tendency to be disrupted by distracting memories in daily life. Sometimes, cues remind us of
things we would prefer not to think about. Confronted with such reminders, we often try to refocus
attention and ignore the unwanted memory. This illustrates the point that having good memory for things
that we have learned isn’t always a virtue, and this highlights the need to control a memory system that is
sometimes too efficient, too able to deliver information, even when such remembrances conflict with our
current goals.
In this article, research is reviewed that indicates that our ability to control distracting memories is
accomplished by executive-control mechanisms that aren’t limited to controlling memory. The authors
argue that the ability to control memory is a special case of a broad class of situations, termed response-
override situations, that are thought to require executive control.
- In response-override situations, one must stop a strong habitual response to a stimulus because of
situational demands. This is accomplished by inhibitory processes that suppress it and enable a
more flexible, context-sensitive control over behavior. These inhibitory processes that control
overt behavior, are also targeted at declarative memories to control retrieval.
In this article, evidence is discussed for the involvement of inhibitory processes in two memory situations
that are likely to require response override:
- The need for selection during retrieval. This is required during retrieval when the goal is to recall
an event or fact from long-term memory in the face of interference from related traces.
- The need to stop retrieval itself. This arises when we confront a cue or reminder and wish to
prevent an associated memory from entering awareness.
In both situations, attempts to limit the influence of activated and potentially distracting memories
impair memory for those traces (connection between our capacity to control retrieval and forgetting).
Inhibitory control in selective memory retrieval
When retrieving specific events or facts, the cues that guide retrieval are typically related to many other
traces. Activation of these other traces interferes with retrieval of the desired item, with the amount of
interference thought to depend on the number and strength of the competitors. Inhibitory control might be
recruited to override competition from prepotent memories so that a target trace can be selectively
retrieved.
If this is indeed the case, then later recall of competing memories should be impaired. The authors found
evidence consistent with this in a procedure called the ‘retrieval practice paradigm’.
- Subjects study lists of categories-exemplar pairs (fruits-banana, drinks-scotch, fruits-orange).
They then perform retrieval practice on half of the exemplars from half of the categories by
completing cued stem-recall tests (fruit-or..?) three times on each practiced item. After a 20-min
delay, they are given a final cued recall test for all the exemplars. Performance can be examined
for: practiced items (orange), unpracticed competitors (banana) and baseline items from
unpracticed categories (scotch).
o Recall of the practiced exemplars was improved relative to recall of the baseline
exemplars, whereas recall of unpracticed competitors was impaired.
This is known as the retrieval-induced forgetting (RIF); remembering makes subjects forget related
memories. This is consistent with the view of inhibitory control.
It can however also be explained without inhibition. Several models of memory can explain RIF through
changes in the relative strength of practiced and unpracticed exemplars. Retrieval practice strengthens
practiced items, which is why on the final test, these strengthened items intrude so persistently that
subjects abandon all efforts to recall unpracticed exemplars.
Other non-inhibitory mechanisms might also contribute. Retrieval practice may for example damage the
association that links the category to the affected exemplar or alter the meaning of the practiced category,
so that the category label is no longer a functional cue for retrieving unpracticed competitors.
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Levy & Andereson (2002). Inhibitory processes and the control of memory retrieval.
There is a tendency to be disrupted by distracting memories in daily life. Sometimes, cues remind us of
things we would prefer not to think about. Confronted with such reminders, we often try to refocus
attention and ignore the unwanted memory. This illustrates the point that having good memory for things
that we have learned isn’t always a virtue, and this highlights the need to control a memory system that is
sometimes too efficient, too able to deliver information, even when such remembrances conflict with our
current goals.
In this article, research is reviewed that indicates that our ability to control distracting memories is
accomplished by executive-control mechanisms that aren’t limited to controlling memory. The authors
argue that the ability to control memory is a special case of a broad class of situations, termed response-
override situations, that are thought to require executive control.
- In response-override situations, one must stop a strong habitual response to a stimulus because of
situational demands. This is accomplished by inhibitory processes that suppress it and enable a
more flexible, context-sensitive control over behavior. These inhibitory processes that control
overt behavior, are also targeted at declarative memories to control retrieval.
In this article, evidence is discussed for the involvement of inhibitory processes in two memory situations
that are likely to require response override:
- The need for selection during retrieval. This is required during retrieval when the goal is to recall
an event or fact from long-term memory in the face of interference from related traces.
- The need to stop retrieval itself. This arises when we confront a cue or reminder and wish to
prevent an associated memory from entering awareness.
In both situations, attempts to limit the influence of activated and potentially distracting memories
impair memory for those traces (connection between our capacity to control retrieval and forgetting).
Inhibitory control in selective memory retrieval
When retrieving specific events or facts, the cues that guide retrieval are typically related to many other
traces. Activation of these other traces interferes with retrieval of the desired item, with the amount of
interference thought to depend on the number and strength of the competitors. Inhibitory control might be
recruited to override competition from prepotent memories so that a target trace can be selectively
retrieved.
If this is indeed the case, then later recall of competing memories should be impaired. The authors found
evidence consistent with this in a procedure called the ‘retrieval practice paradigm’.
- Subjects study lists of categories-exemplar pairs (fruits-banana, drinks-scotch, fruits-orange).
They then perform retrieval practice on half of the exemplars from half of the categories by
completing cued stem-recall tests (fruit-or..?) three times on each practiced item. After a 20-min
delay, they are given a final cued recall test for all the exemplars. Performance can be examined
for: practiced items (orange), unpracticed competitors (banana) and baseline items from
unpracticed categories (scotch).
o Recall of the practiced exemplars was improved relative to recall of the baseline
exemplars, whereas recall of unpracticed competitors was impaired.
This is known as the retrieval-induced forgetting (RIF); remembering makes subjects forget related
memories. This is consistent with the view of inhibitory control.
It can however also be explained without inhibition. Several models of memory can explain RIF through
changes in the relative strength of practiced and unpracticed exemplars. Retrieval practice strengthens
practiced items, which is why on the final test, these strengthened items intrude so persistently that
subjects abandon all efforts to recall unpracticed exemplars.
Other non-inhibitory mechanisms might also contribute. Retrieval practice may for example damage the
association that links the category to the affected exemplar or alter the meaning of the practiced category,
so that the category label is no longer a functional cue for retrieving unpracticed competitors.
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