Jones
et al. outline two theoretical accounts that have been given for why memory
conjunction errors occur. Memory conjunction errors occur when discrete
pieces of information (i.e., features) from two distinct memory events
are inappropriately bound together producing a memorial event that was
never experienced in the past. For example, a person might study blackmail
and jailbird, but when they later try to remember what they saw they remember
blackbird. Blackbird was never experienced but both features black and
bird were studied.
The
representational account proposes that we retain specific types of memory
representations for stimuli experienced in the past. For each event that
is represented in memory there are thought to be two types of representations
encoded, featural and configural.
Features
are basic level representations (e.g., shape, sound, color, form). These
representations are bound to together at retrieval to form a coherent global
representation of a past event. This binding process occurring at retrieval
is guided by the configural representation, which contains the location
of features in relation to one another. Memory conjunction errors occur
when there is a failure to retrieve configural information at the time
of test. This lack of configural information limits a person’s ability
to accurately remember how features were originally put together. In addition,
configural information may not be encoded at study, and thus, would not
be available at the time of test to appropriately piece features back together.
According to this explanation memory conjunction errors can result from
failures during encoding and retrieval.
Memory
conjunction errors can also occur when the configural information is encoded
inaccurately (Kroll, Knight, Metcalfe, Wood, & Tulving, 1996). In other
words, conjunction errors can result from a failure at the time of encoding
to accurately store the relationship of the different features to one another.
This notion assumes that features presented close in time to one another
can become inappropriately bound together, leaving an inaccurate configural
trace. This notion is also similar to more recent work by Hannigan
and Reinitz (2000) and Reinitz
and Hannigan (2001). According to the arguments given by Kroll et al
and Reinitz and Hannigan (2001) time is a fundamental component to inappropriately
binding features together at study.
The
featural explanation can account for memory conjunction errors quit well,
but it does not account for feature errors. A feature error happens when
a person is presented with something (e.g., jailbird), and they inaccurately
accept a distractor item with jail in it (e.g., jailhouse). However, the
second part of this pair was never presented during encoding (e.g, house).
Therefore, there should not be a feature representation for this second
part.
The
procedural account focuses on the processes evoked by the task and does
not implicate individual representations. Instead Jones, et al. contend
that conjunction errors can be accounted for by a familiarity component
of a dual process model of memory. Familiarity is a fast judgment of the
likelihood that something presented at test was presented at study. Recollection
is the second component and is a slower, controlled process. When a person
recollects something they are aware of what happened in the past. By the
logic of dual process models, hits on a recognition test result from both
the familiarity and the recollection processes. But feature errors and
conjunction errors occur only when recollection fails and there is reliance
upon familiarity. If a person was to recall the context of the feature
in a feature distractor or the set of features in a conjunction distractor
the person would reject the distractor as old. The assumption made by these
authors is that memory conjunction errors occur when there is familiarity
for a conjunction distractor in the absence of recollection.
The
following experiments were designed to test the influence of shifts in
the modality of the presentation of study words and test words on rates
of memory conjunction errors.
Experiment 1
Three
questions addressed by the first experiment
Recognition
Test Items
Experiment 2
Experiment
2 differed from experiment 1 with the addition of feature distractor items.
These items were compound words that had one word that was studied previous
but the other word in the compound word had not been studied previously.
In addition, there was the addition of a between participant manipulation
of test modality. Half of the participants completed a recognition test
in which the test words were presented audibly and the other half of the
participants completed a recognition test in which the words were presented
visually.
Results:
The
authors predicted and observed the following pattern of recognition responding,
TARGET > CONJUNCTION > FEATURE > NEW WORDS. Again the authors did not observe
any modality effects. As can seen in Table 2 rates of hits and false alarms
did not different between the different test modalities or the different
study modalities.
Experiment 3
The
researchers failed to observe a modality effect in the first two experiments,
but this could be the result of recollection masking rates of responding
to conjunction and feature items based on familiarity. Therefore, Jones
et al. manipulated the ability of participants to rely on recollection
by limiting the amount of time that participants had to make their recognition
responses. Speeded recognition responding decreases the ability of participants
to use the recollection process. This should allow for potential differences
in levels of familiarity resulting from differences in modalities between
study and test to be observed.
Results:
As
predicted by the authors the following differences were observed in rates
of responding old to the different types of recognition items, TARGET >
CONJUNCTION > FEATURE > NEW WORDS. Again there was no modality effect observed.
Although there was a marginally significant decrease in hits to targets
when there was a mismatch between modalities at study and test.
Experiment 4
Experiment
4 was similar to the previous two experiments except for the addition of
a within participant manipulation of response time allowed at test, and
a between participants manipulation of study modality. Unlike the previous
experiments all study words were either presented aurally or visually to
participants.
Results:
There was a main effect for modality and a main effect the amount of time
allowed to make a decision. False alarms more prevalent in the auditory
study group and false alarms were also more likely to commit false alarms
in the short deadline responding group.
The
mean acceptances of targets, conjunction lures and feature lures were corrected
by subtracting out the rate of accepting completely new words. These means
demonstrated yet again that there was no modality effect. However, the
speeded response did decrease rates of responding to targets, but not rates
of responding to conjunction and feature lures.
From
the results of the final experiment the researchers concluded that responding
to targets is based on both recollection and familiarity but responding
to conjunction and features is based entirely upon familiarity. Therefore
the conclusion is that there is no need to introduce new mechanisms to
account for false alarms to conjunction lures on recognition memory tests.
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