The Psychological Record, 2004, 54, 199-206
RELEASE FROM PROACTIVE INTERFERENCE WITH POSITIVE AND
NEGATIVE WORDS
F. RICHARD FERRARO and BRENT KING
University of North Dakota
Using the release from proactive interference (RPI) task, college
students (n =40) received 4 trials comprised of 3-word triads of either
positive (P) or negative (N) words. Word-triad recall served as the
dependent measure, and results revealed typical buildup of PI (i.e.,
no significant group x trial interaction across Trials 1-3). Significant
RPI was also observed when examining performance across Trials
3-4, and PI release was greater in those subjects who experienced
a valence shift from P words to N words or from N words to P words
across Trials 3-4. No release was observed in the control group and
the word-triad recall performance of the control group continued to
decline across trials. Results are discussed in terms of using the RPI
paradigm with emotionally valenced stimuli and including clinically
relevant samples.
The release from proactive interference (RPI) task continues to be a
useful memory encoding tool (Wickens, 1972; Wickens, Born , & Allen ,
1963; Perez & Kee, 2000) . This task examines short-term memory
performance and interference and follows the methodology of the BrownPeterson short-term memory procedure. Trials (usually four) are
presented consecutively to subjects and consist of triads of three objects
(words, pictures, etc). After each trial is presented and presumably
encoded, a distractor task (e.g., counting backwards, crossing out letters
or numbers) is given, followed by free recall of the items comprising the
most recent triad.
On control trials, the items that comprise the triads include words
similar on some dimension across Trials 1-4 and are based on some
predetermined dimension (all high-frequency words, all nouns, all verbs,
etc). On experimental, or release, trials, information in the three-item
triads is the same across the first three trials (as in the control trials) and
then this information shifts to some other dimension or characteristic on
Trial 4 (e.g., all nouns on trials 1-3, all verbs on Trial four). If the specific
Correspondence may be addressed to F. Richard Ferraro, Department of Psychology,
Box 8380, University of North Dakota, Grand Forks, NO 58202-8380 . (E-mail :
[email protected]).
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FERRARO AND KING
dimension or information contained in the triads is spontaneously
encoded by subjects, two events occur. First, there is a decrease in recall
performance across Trials 1-3, termed buildup of proactive interference.
Second, on shift trials (going from Trial 3 to 4), there will be a sudden and
significant increase in recall performance, termed release from proactive
interference (RPI). This RPI indicates that the information shift from Trial
3 to Trial 4 was sufficient enough in encoding to alter performance.
Conversely, the absence of PI release means that there were no
significant changes in the encoding dimension.
Although several stimulus types (words , pictures) , modalities
(auditory, visual) , and age groups (infants, young adults) have been
tested using the RPI task (Esrov, Hall, & LaFaver, 1974; Reutener &
Fang , 1984; Reutener & Graybill , 1978; Tyrrell, Snowman , Beier, &
Blanck, 1990), relatively little work has employed the RPI task with
emotionally valenced stimuli. A study by Wickens and Clark (1968) is a
lone exception.
Wickens and Clark conducted th ree experiments to determine if
words are encoded for short-term memory (STM) storage by the
connotative meaning of the extremes of the three dimensions (evaluation,
potency, activity) of the Osgood (Osgood, Suci , & Tanenbaum, 1957)
semantic differential. Results revealed that words at each end of these
various semantic differential scales are homogeneously encoded into
STM and, thus, represent a psychological class differing from words at
the opposite end of the scales. In short, subjects are apparently encoding
verbal materials by some meaning characteristic which is associated with
the extreme ends of these three Osgood scales, thereby offering support
for the validity of the bipolarity of these various scales.
Finding only one study performed over 30 years ago that employed
the RPI task with presumably emotional stimuli is intriguing, especially
because there are now several reports in the literature suggesting that
emotionally valenced stimuli are encoded and processed at both an
unconscious and conscious level (Denny & Hunt, 1992; Richards,
French , Johnson, Naparstek, & Williams, 1992; McCabe, 1999; Watkins,
Vache, Verney, & Mathews, 1996). The information processing attributes
of emotionally valenced stimuli have much relevance to clinical issues
with individuals who may be depressed, anxious, or both.
For instance, several models of information processing in these (and
other) clinically relevant groups have been proposed that have yielded
several major insights and revelations about the specific cognitive
mechanisms that operate in these groups. Specifically, Friedman, Thayer,
and Borkovev (2000) have indicated how memory biases for disordercongruent information processing relates to the disentanglement of
various clinical psychopathologies. Other methodologies have been
advanced to investigate the information processing patterns of various
psychopathologies, and these have included , but are not limited to,
attentional orienting (Bohlin & Kjelberg, 1979), imagery (Bryden & Ley,
1983), cardiovascular (Friedman & Thayer, 1998), Stroop (Moog,
RELEASE FROM PROACTIVE
201
Mathews, & Weinman, 1989), and heart rate (Thayer, Friedman,
Borkovec, Johnson , & Molina, 2000). Use of the RPI task may
complement those studies presently available that report memory biases
in information processing in clinical populations by revealing the type and
depth of encoding emotionally valenced stimuli. That is, use of the RPI
task with studies on emotional processing would result in an increase in
knowledge about how emotional semantic attributes of memory are
activated and made available for subsequent processing.
Use of the RPI task results in measures of memory encoding which
occur without intention or deliberate strategic processing. Additionally,
results from RPI studies allow for an index of spontaneous encoding of
stimulus attributes in memory. The procedure, most notably the release
from PI performance pattern, can also gauge the level of interference
experienced by the participant during this spontaneous encoding of
information. Few methodologies exist that examine spontaneous
encoding of stimulus attributes in memory and, to date, no such studies
can be located in the cognition and emotion literature, at least using
verbal materials, that have tested this assumption. One study (McDonald
& Prkachin , 1990) found that deficits in the spontaneous encoding of
negative emotion (using posed facial expressions) and in nonverbal
expression are central to the disorder alexthymia. This, however, is the
lone exception of a study investigating spontaneous encoding and
negative emotion.
Thus, use of the RPI task with emotionally valenced stimuli adds to the
list of tasks noted above by allowing for examination of spontaneous
encoding of emotionally valenced material. Additionally, simply encoding
information into memory does not guarantee the spontaneous use of that
information as the situation or setting arises. Use of the RPI task will allow
for an examination not only of how information is encoded, but to what extent
that emotional information can be spontaneously encoded and used at a
later time, if at all.
If the RPI task shows promise with emotionally valenced stimuli,
several patterns of behavior should be observed in the present
experiment (see also Wickens & Clark, 1968). First, there should be no
difference between experimental and control groups across Trials 1-3.
Recall performance should decrease across these three trials, indicating
a buildup of PI. This is a standard finding in the RPI literature when the
initial Trial 1-3 triads contain items that are similar to each other on some
dimension (all nouns, all verbs , etc.). Likewise, there should be a
difference in recall performance between the experimental and control
groups across Trials 3-4. The control group should continue to show a
recall performance decrement, or at least no difference, across Trials 34. Conversely, the experimental (or shift) group should reveal an increase
in recall performance across these same trials which would be indicative
of a release from PI. This pattern of behavior is also a classic and robust
finding in the RPI literature. These various issues were investigated in the
present experiment.
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FERRARO AND KING
Method
Participants
Forty college undergraduates (M age = 21 years) participated for
course credit. Twenty were randomly assigned to the control group (10
received all positive words across Trials 1-4 [PPPP], 10 received all
negative words across Trials 1-4 [NNNN], while 20 were randomly
assigned to the experimental group (10 received PPPN, 10 received
NNNP). Gender was not examined as a factor. No other demographic or
psychological data were recorded.
Materials
Each subject received a 13-page booklet containing pages in the
following order: (a) consent form, (b) Trial 1 page, (c) distractor page, (d)
Trial 1 recall page, (e) Trial 2 page, (f) Trial 2 distractor page, (g) Trial 2
recall page, (h) Trial 3 page, (i) Trial 3 distractor page, (j) Trial 3 recall
page, (k) Trial 4 page, (I) Trial 4 distractor page, (m) Trial 4 recall page.
Pages were all 8 x 11.5 in. Word triads were centered on each page, were
arranged in a vertical column, and were printed in uppercase letters.
Distractor pages consisted of 625 two-digit odd and even numbers and
subjects were instructed to cross out all the even numbers or all the odd
numbers. Recall pages instructed subjects to recall as many of the three
previous words as they could in any order and to write them down. Also,
these free recall pages contained instructions that said not to turn the
page until the experimenter said it was acceptable to do so.
Triads consisted of words that had been rated as either positive or
negative in their emotional valence and were gathered from several
sources (Gotlib, McLachlan, & Katz, 1988; Kuiper & Derry, 1982;
Mathews, Mogg, May, & Eysenck, 1989). All stimuli were matched as
closely as possible on part of speech, number of syllables, number of
letters, and word frequency. No other word characteristics were
manipulated or identified. The Kucera-Francis (K-F) frequency value for
the positive words (M = 3.67, SO = 2.16) did not differ from the K-F value
for negative words (M = 3.47, SO = 2.45) t = .24. Number of syllables did
not differ for positive (M = 2.53, SO = .83) or negative words (M = 2.53,
SO = .99). Finally, number of letters did not differ for the positive (M =
6.93, SO = 1.33) or negative words (M = 7.67, SO = 1.88) t = 1.25.
Assignment of positive and negative words to specific triads and specific
trials was done completely randomly with the constraint that Trial 4 stimuli
were similar for both groups. Additionally, an attempt was made to ensure
that each triad occurred equally often on each trial.
The positive words were adorned, amiable, bliss, genial, gratified,
jolly, jovial, kindness, merry, playful, prosper, rejoice, sociable, talented,
and vivacious. The negative words were blamed, detested, discontented,
downcast, forlorn, gloomy, glum, inferior, melancholy, punished, unlucky,
unwanted, unworthy, wilted, and withdrawn.
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203
Procedure
Subjects were tested as a group and received one of four possible
test booklets, containing either all positive (P) or negative (N) word triad
stimuli (PPPP, NNNN) across Trials 1-4 or booklets in which word triads
on Trial 4 switched from a positive word triad to a negative word triad or
vice versa (PPPN, NNNP). Following completion of the consent form, the
experimenter asked subjects to turn to the Trial 1 page. Time per word
was not measured. Subjects were told to read the three words to
themselves Silently. After 30 seconds, the experimenter asked subjects to
turn to the distractor page. Subjects were allowed 2 minutes to work on
the distractor page. It should be noted that none of the subjects
completed the distractor task page within the 2-min period. After 2
minutes, the experimenter asked subjects to turn to the recall page and
subjects had 1 minute to recall as many of the previous three words in
any order as they could. This basic procedure was followed across all
four trials. The entire experiment lasted no more than 15-20 minutes.
Results
Recall protocols were scored for number of words correct out of three
possible (order was not analyzed) and this value (mean number correct)
served as the dependent measure for a series of analyses of variance
(ANOVAs). Recall intrusions were not scored or analyzed. Table 1
displays recall performance as a function of group (control, experimental)
and trial (1-4).
Table 1
Statistics for Words Recalled as Function of Group and Trial
Trial
Group
Experimental
M
SO
Control
M
SO
2.25
.64
2.00
.73
2
3
2.00
.65
1.90
.79
1.40
.75
1.45
.83
4
2.75
.55
1.20
.83
Note. Mean number correct is out of three possible.
First, PI buildup was examined in a 2 (Group) x 3 (Trials 1-3) mixed
ANOVA. No main effect of group was observed, F(1, 38) = .29. However,
the main effect for trial was significant, F(2, 76) = 18.68, MSe = .284, P <
.01, eta-squared = .33 and revealed that mean recall performance
decreased across Trials 1-3. More importantly, there was no Group x Trial
interaction (F = .79). Lack of an interaction indicates that both control and
experimental groups showed statistically equivalent recall performance
across Trials 1-3, and thus, statistically equivalent PI buildup.
Next, a 2 (Group) x 2 (Trials 3-4) mixed ANOVA was performed to
examine any release from proactive interference. There was a main effect
of group, F(1, 38) = 11.09, MSe = 1.01, P < .04, eta-squared = .23 and a
main effect of trial, F(1, 38) = 55.40, MSe = .11, P < .01, eta-squared =
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FERRARO AND KING
.59. These main effects were qualified by a significant Group x Trial
interaction, F(1, 38) = 117.21, MSe = .11, p<. 01, eta-squared = .76. This
interaction revealed that the experimental group displayed significant
release across Trials 3-4, t(38) = 6.43, P < .01, whereas the control group
did not, t(38) = .96, P > .05.
Discussion
Using the RPI methodology, a significant release from proactive
interference occurred when Trials 3-4 involved a positive to negative or
negative to positive valence shift. The present results not only replicate the
basic RPI effect (Wickens, 1972), they highlight the relevance of employing
a positive/negative stimulus dimension for spontaneous short term memory
encoding (see also Wickens & Clark, 1968). Our results indicate that such a
stimulus dimension is adequately encoded into memory.
Groups that include patients with clinical depression and anxiety
could benefit from use of this task as a means of exploring the underlying
cognitive performance in these diverse groups. For instance, and with
regard to anxiety, McNally (1995) has proposed that cognitive biases
influence the maintenance and etiology of pathological anxiety. Based on
this expectation, one would predict an even greater release from PI in
high-anxiety individuals compared to low-anxiety individuals or control
individuals. Likewise, in the depression literature, the mood-congruent
memory (MCM) effect (Watkins et aI., 1996) asserts that sad or
depressed individuals have a tendency to remember information
consistent with their particular mood state. Thus, in the release from PI
task, one would expect that sad or depressed individuals, as compared
to non-depressed or non-sad individuals, would show greater RPI for
words related to depression, especially if they have spontaneously
encoded them during the experiment. Although depression and anxiety
were not explicitly manipulated or measured in the individuals in the
present experiment, future experiments should test the RPI task with
these various clinical groups, manipulating the specific type of stimuli
(positive, negative, neutral, depression, anxious, etc.).
To summarize, the present results have indicated that positive and
negative words show differential RPI, validating Wickens and Clark
(1968). When triad content shifted from all positive words to all negative
words (and vice versa) going from Trial 3 to Trial 4, a reliable release from
PI was observed. No such release was observed when triad content
remained constant across Trials 3-4. Future studies should examine
clinical groups in an effort to expand this RPI task to these groups as well
as to reveal additional information relating to emotional information
processing mechanisms in these groups. The RPI task is relatively easy
to administer and score and may provide important insight into cognitive
and affective information processing mechanisms. In particular, insight
would be gained regarding how the various disorders relate to the
spontaneous encoding of information in STM and how this encoding
affects subsequent performance.
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