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8/3/2019 Basden Basden 1996

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retrieval inhibition as an additional mechanism, but did not tie it to a specific

method. We have argued (Basden et al., 1994; Basden, B asden, & Gargano,

1993) that different mechanisms are responsible for directed forgetting with the

two methods, but we have proposed that retrieval inhibition underlies directed

forgetting with the list method, and that differential processing of Remember

and Forget targets underlies directed forgetting with the item method. Inaddition, we have assumed that relational (organisation) processing occurs to a

greater extent with the list method than with the item method, and that item-

specific processing occurs to a greater extent with the item method than with the

list method. In a com prehensive review of the directed forgetting literature,

Johnson (1994) drew a similar conclusion. She attributed greater recall of

Remember than of Forget targets with the list method to segregation and

selective search of each list of targets followed by inhibition of the to-be-

forgotten list. With the item method, segregation and retrieval inhibition are not

required because only the set of Remember targets is stored and searched.

Three lines of evidence support the position that retrieval inhibition occurs

with the list method and not with the item method. First, the item method

typically yields greater directed forgetting than the list method on recall tests, a

result that should be expected if Forget targets are more extensively processed

with the list method than with the item method. Second, the item method yields

directed forgetting on recognition tests, but the list method does not. If items are

less well processed at storage (as we believe is the case with the item method),

recognition memory should be affected. If a set of equally well-processed items

is inhibited from retrieval (as we believe in the case of the list method), a test

that de-emphasises retrieval should be unaffected. Third, the re-presentation of

targets on a recognition test seems to effect a ``release from inhibition on a

subsequent recall test when the list method is used, but not when the item

method is used1

(e.g. Basden et al., 1993; Bjork, 1989). Re-presentation of both

Remember and Forget items would not be expected to eliminate a processingdeficit for the Forget items, but might very well overcome retrieval inhibition.

According to this distinction between relational and item-specific processing

(Einstein & Hunt, 1980; Hunt & Einstein, 1981), procedures that focus the

subjects attention on the list as a whole (or at least on large sections of it)

encourage the identification of relationships among the i tems, whereas

procedures that focus the subjects attention on individual items emphasise

information that is item-specific. T hus, the list m ethod of directed forgetting

w o uld e nc our ag e r ela ti on a l p roc e ssi ng w he re as th e it em m e th od w ou ldencourage item-specific processing. This is not to say, of course, that either

634 B A S D E N A N D B A S D E N


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suggesting that the mix of relational and item-specific information is influence

by the method of directed forgetting. Relational processing should facilitate lis

method directed forgetting because in this case suppression of an entire, alread

processed list must occur. Item-specific processing should facilitate ite

method directed forgetting because in this case individual targets must b

forgotten at the time they are undergoing processing.If the item method encourages item-specific processing and the list metho

encourages relational processing, and if directed forgetting results from

processing deficit with the item method and from retrieval inhibition with th

list method, then factors that enhance item-specific processing should increa

the magnitude of directed forgetting with the item method, and factors th

enhance relational processing should increase directed forgetting with the li

method. In Experiment 1, we manipulated the study format as a means

encouraging either relational or item-specific processing. Our expectation w

that the relative magnitude of directed forgetting with the two methods wou

vary with study format.

E X P E R IM E N T 1

In this experiment one group of subjects attempted to memorise a set of anim

pictures and two other groups of subjects attempted to memorise a list of nam

for those pictures. The subjects in one of the two latter groups w ere given simp

learning instructions and those in the other group were told to form a ment

image of the referent of each target. A few prior studies have employed imag

or pictures in the context of directed forgetting (Bray, Justice, & Zahm, 198

Bugelski, 1970). Unfortunately, no firm conclusions could be drawn from the

previous studies.

According to Hunt and his colleagues, item-specific processing is encourage

either by forming images of the targets (Hunt & Marschark, 1989) or bstudying pictures corresponding to the targets (Hunt & McDaniel, 1993). Hu

and McDaniel have also argued that simple presentation of a categorised list f

learning encourages relational processing. As mentioned earlier, item-metho

directed forgetting is usually greater than list-method directed forgettin

According to our analysis, this difference in the m agnitude of directed forgettin

should be greater when subjects study pictures or study words with image

instructions that when they study words alone, particularly when the wor

belong to a single category.One interpretation of directed forgetting is that contextual information abo

D I R E C T E D F O R G E T T I N G 63


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retrieval inhibition. Unfortunately, a potential source of confounding is present

if subjects base their judgements of list membership on item strength. If this

were the case, judgements of list membership might not reflect context

information alone. A more direct measure of memory for context information is

to have subjects indicate the approximate serial position of previously recalled

targets. Tzeng, Lee, and Wetzel (1979) introduced this technique. With the itemmethod they found that serial position information was remembered better for

Remember than for Forget targets. No control subjects were tested, so no

absolute assessments were possible.

The results of Tzeng et al. are equally consistent with the idea that Forget

items are less extensively processed with the item method. If Remember and

Forget targets are equally well processed with the list method, then accuracy of

serial position information should be equivalent for the Forget and Remember

items with this method. However, if Geiselman et al. are correct and context

memory is reduced by directed forgetting instructions, then memory for serial

position of F orget targets should be affected with both the item and the list

methods.

In this experiment we asked our subjects to indicate approximate serial

positions for the items they recalled. To determ ine the influence of directed

forgetting instructions on absolute memory for contextual information, we

included control subjects who did not receive directed forgetting instructions. If

contextual information is lost during directed forgetting, then memory for serial

position should be less accurate for Forget targets in the experimental conditions

than in the control conditions.

Although control subjects were included to permit measurement of absolute

loss of contextual informa tion, their inclusion also permitted us to com pare the

absolute effects of directed forgetting instructions on Remember and Forget

targets for each of the two methods. Past research has shown that directed

forgetting instructions yield not only lower recall of Forget targets, but alsogreater recall of Remember targets (see Bjork, 1972).

Method

Subjects. We tested 194 students enrolled in introductory psychology

classes at California State University, Fresno. Their participation was in partial

fulfilment of course requirements. Approximately 22 subjects were tested in

each of the nine treatment conditions.



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was designated Forget and Remember equally often across groups. Order w

varied across groups to ensure that particular targets did not consistently occup

favourable serial positions across m ethods. Subjects responded by writing the

recall on lined pages included in their response booklets.

Design. A 3 2 2 mixed factorial design was employed with studformat (pictures, words with imagery instructions, or words without image

instructions) and method ( list or i tem) as between-subjects factors an

instruction (Remember or Forget) as a within-subject factor. Three outsid

control groups were also tested, one with each of the three study format

Subjects in these groups were not given directed forgetting instructions.

Procedure. Groups of up to six subjects at a time were assigned to testin

conditions in accordance with a block-randomisation schedule. Subjects we

given instructions appropriate to their study format prior to target presentatio

For the image study format, subjects were instructed to form an image of eac

word as it was presented to them. For the picture and word study format

subjects were simply instructed to do their best to recall all targets. A blan

screen or a spot of l ight of 1.1 second duration followed each target for a

subjects. Subjects tested with the item method were given the followin

additional instructions:

After each item has been on the screen for a few seconds, it will be followed by a

blank screen or a spot of light. A blank screen means you are to forget that item but

a spot of light means you are to remember that item.

Subjects tested by the list method were not told to differentiate among items an

were told to ignore the presence or absence of lights.

After subjects had read the initial instructions, they were shown the words pictures individually at a three-second rate. After the first 12 targets had bee

presented, subjects tested by the item method were told to rest for a few second

Subjects tested by the list method were given directed forgetting instructions f

the first list. Thus, the time interval between list halves was equivalent for th

two methods. Then the remaining 12 targets were presented.

Target presentation was im media tely followed by a distractor task intended

purge short-term memory. Subjects com pleted simple arithmetic problems

their response booklets for 30 seconds; then they were instructed to write many of the targets they had studied as they could remember, including both th



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through to ``6 if it occurred among the last four targets (cf Tzeng et al., 1979).

After the experiment was over, the subjects were told the purpose of the forget

instruction and were asked not to discuss the experiment with other potential

subjects.

Results

The dependent variable in free recall was the proportion of Remember or Forget

targets recalled. For control subjects, targets that occupied the same serial

positions as actual Remember and Forget targets in the experimental conditions

were designated nominal Remember and Forget targets. Thus, determination of

nominal Remember and Forget targets for individual control subjects depended

on whether the comparison was with list method or item method experimental

subjects. Mean recall proportions for each of the conditions are shown in Table 1.

A mixed three-factor analysis of variance was performed with method and

study format as between-subjects factors and instruction as a repeated measure.

The three-factor interaction was significant, F(2, 127) = 3.53, M Se = 0.036.

Subsequent analysis revealed that the simple interaction between method and

instruction was significant for pictures, F(1, 42) = 4.21, MSe = 0.032; and for

words with images, F(1, 45) = 14.89, M Se = 0.027, but was not significant for

words w ithout images, F


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M Se = 0.037, for words with images, F(1, 22) = 95.86, M Se = 0.022, and f

words without images, F(1, 19) = 15.62, M Se = 0.043. With the list m ethod, th

magnitude of directed forgetting was also statistically significant for all thr

study formats: for pictures, F(1, 21) = 12.47, M Se = 0.038, for words wi

images, F(1, 23) = 11.12, MSe = 0.031, and for words without images, F(

21) = 20.45, MSe = 0.048.

As mentioned earlier, we compared the list method and item method directe

forgetting subjects with the same control subjects. This necessitated separa

three-factor analyses of variance for each method, with study format and grou

(experimental vs. control) as between-subjects factors and instruction as

repeated measures factor. For the item method analysis, the effect of stud

format was significant, F(2, 120) = 7.77, MSe = 0.035. Images were recall

better than pictures or words. The interaction between instruction and group w

significant, F(1, 120) = 65.21. Tests of simple effects confirmed that recall

Remember targets was greater for experimental than for control subjects, F(

120) = 13.04, M Se = 0 .158 ; b ut rec all of Fo rg et t arg ets w a s poo re r f

experimental than for control subjects F(1 120) = 46 06 MSe = 0 1922

F

FIG. 1. Magnitude of directed forgetting as a function of study format and instruction.



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the list method analysis, the interaction between group type and instruction was

again significant, F(1, 123) = 27.87. As in the analysis of the item method, recall

of Remember targets was greater for experimental than for control subjects, F(1,

123 ) = 8.03, M Se = 0 .2 01; bu t r eca ll of F or ge t ta rge ts w as p oo re r f or

experimental than for control subjects, F(1, 123) = 17.75, M Se = 0.017.

An analysis conducted on the proportion of correct serial position placementsfor the item method yielded a significant main effect for instruction, F(1,

60) = 5.64, M Se = 0.054. The proportion of correct placements was 0.50 for

Remember targets and 0.40 for Forget targets. A similar analysis for the list

m ethod yielded no significant effects, the mean propor tion of c orrect placements

was 0.42 for Remember targets and 0.48 for Forget targets.

An analysis was conducted on the proportion of correct serial position

placements of Forget i tems contrasting directed forgetting subjects with

controls. Subjects placed Forget targets equally accurately in the experimental

and control conditions, Fs < 1. This held true for both the item and list methods.

Discussion

W e have hypothesised that study formats encouraging item-specific processing

would increase directed forgetting m ore with the item method than with the list

m ethod. This hypothe sis was confirmed . The difference in magnitude of directed

forgetting with the item and list methods was greater when subjects studied

pictures or words for which they formed images than when they simply studied

words. Directed forgetting was actually equivalent for the two methods when

subjects studied words w ithout forming images. The se results are consistent with

our distinction between item and list methods, i.e. that relational processing

underlies directed forgetting with the list method, but that item-specific

processing underlies directed forgetting with the item method.

The present results are not consistent with those of Bugelski (1970), whoreported an absence of directed forgetting with the item method when subjects

were asked to form images of the targets they studied. His report is quite sketchy

with regard to procedures, but we assume that they differed from our own in

some important way. Our results are consistent with those of Bray and his

colleagues, e.g. Bray et al. (1983). These investigators reported robust directed

forgetting when subjects studied pictures.

Bugelski had argued, on the basis of his failure to find directed forgetting,

that subjects could not inhibit targets for which they had formed images. On thebasis of our own results we would argue that subjects did not carry out extensive



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Remember items. In the present study this occurred with both the list and ite

methods. Recall was poorer for Forget targets and better for Remember targe

as compared with controls. Bjork (1970) has argued that Remember targets a

subject to less interference in the experimental conditions. This argument cou

be applied to either method of directed forgetting.

If differential processing underlies item-method forgetting, then seriposition information should be better for Remember than for Forget items wi

this method. If differential processing is not responsible for list-method directe

forgetting, then serial position information should be the same for Rememb

and Forget items with this method. As predicted, memory for serial positio

information was better for Remember than for Forget i tems with the ite

method, but not with the list method. These results support our position.

To test the hypothesis expressed by Geiselman et al. (1983) that direct

forgetting occurs when subjects lose access to contextual information, w

compared accuracy of serial position information for Forget targets in th

experimental and control conditions. Although Geiselman et al. reported th

memory for list membership of Forget items was greater for control than fo

experimental subjects, we found no corresponding difference in the accuracy

memory for serial position. Furthermore, our results were quite similar with th

list and item methods. Thus, our results do not support the hypothesis th

directed forgetting results from loss of contextual inform ation. O f course, a qui

different picture might emerge if recollection for serial position of all items ha

been assessed.

Thus, results of Experiment 1 were consistent with the hypothesis th

retrieval inhibition and relational processing underlie directed forgetting wi

the list method, but that differential item-specific processing underlies directe

forgetting with the item method. In Experiment 2, we compared the influence

the list- and item-m ethod directed forgetting on performance in an impli

memory test. Current research and reviews (e.g. Brown & Mitchell, 199 Thapar & Greene, 1994) indicate that levels of processing manipulations ma

influence priming on implicit tests. If, as we suggest, R emember targets a

more extensively processed than Forget targets with the item method, then item

method directed forgetting may occur on implicit tests but list-method direct

forgetting should not.


Directed forgetting on implicit tests has sometimes been observed with the ite



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(e.g. word fragment cued recall, stem-cued recall, recognition, and word

association) do not produce list-method directed forgetting (see Basden et al.,

1993). List-method directed forgetting instructions appear to act on the list as a

whole rather than on individual items.

In previous experiments that obtained item-method directed forgetting on

implicit tests (e.g. MacLeod, 1989), perceptual tests such as word fragmentcompletion were used. Such tests are typically less sensitive to differential

processing (see Roediger & McDermott, 1993) than are conceptual tests (tests

relying on meaning). Thus, demonstrations of item-method directed forgetting

should be easier to obtain on implicit conceptual tests. In research reported

earlier we failed to observe item-method directed forgetting with an implicit

word association test (Basden et al., 1993, Experiments 1 & 2). However, this

failure may have resulted from a floor effect, as priming was not statistically

significant with the conceptual test we used. The present experiment represents

another attempt to obtain item-method directed forgetting with an implicit

conceptual test. The list method was included for purposes of comparison.

After studying a list of low-frequency words with either item- or list-method

directed forgetting instructions, the subjects were given an implicit test of

general knowledge. Definitions of targets and distractors were provided at the

time of the test, and subjects were instructed to respond to each of them with the

first word that came to mind. Low-frequency words were used because such

materials typically yield higher levels of priming than do high-frequency words

(Roediger & McDermott, 1993). As this test, like other implicit tests, includes

item-by-item cueing, i t should be sensit ive to differential processing of

Reme mber and Forget items of the sort we believe the item method encourages.

Therefore, we expected directed forgetting w ith the item method but not with the

list method.

After completing the implicit general knowledge test, subjects were asked to

free recall the Remember and Forget targets. We expected directed forgettingwith the list method as well as with the item method on this test, because free

recall is sensitive to the retrieval inhibition we believe occurs with the list

method. We expected greater directed forgetting with the item method than with

the list method as in our previous research.

Method

Subjects. We initially tested 68 subjects and later added 69 more subjects.We also tested 28 similar subjects in a pilot study used to assess the materials.



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Dictionary. The materials were then piloted to confirm that prospective subjec

could match the words with their definitions. These definitions were used

prepare a test of general knowledge.

All materials were presented using a microcomputer. The subjects typed the

responses at the computer keyboard.

Design. We employed a mixed two-factor design with method (item or lis

as a between-subjects factor and instruction (Forget or R emember) as a withi

subject factor. The dependent measure was the number of experimente

designated terms produced on the test of general knowledge and on th

subsequent free recall test.

Procedure. Subjects were assigned to the method of directed forgetting

accordance with a block-randomisation schedule. After entering the conditio

code at the computer keyboard, the experimenter left the test cubicle; th

remainder of the procedure was automatically administered. The programm

randomly selected a study list of 48 targets and 48 distractors from the corpus

192 words. The 48 list members were randomly separated into 24 Rememb

and 24 Forget targets. Individual random presentation and testing orders we

also program-generated. Prior to list presentation all subjects w ere informed th

their ability to remem ber list membe rs would be tested later. Subjects tested wi

the item method were also given the following instructions:

After each word has been on the screen for a few seconds, a brief signal will tell

you whether to REMEMBER it or FORGET it. If the signal is REMEMBER you

should be prepared to recall the word later, but if the signal is FORGET you can

forget the word.

After reading these initial instructions, all subjects were shown the targeindividually at a six-second rate. For subjects tested with the item metho

``REMEM BER or ``FORGET joined each item during its final three secon

of exposure. After the first 24 targets had been presented, subjects tested wi

the item method w ere told to rest for a few seconds and subjects tested with th

list method were given the following directed forgetting instructions:

The list you have just studied was only for practice. You can forget it now. The list

you will see next is the one we want you to remember, so forget the practice listand concentrate on this new list.



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thought was associated with each commodity on the screen, e.g. ``Georgia for

PEACHES. Subjects continued with this task until they had responded to all

commodities or until 30 seconds had elapsed without a response.

Subjects were told that the general knowledge test, which immediately

followed the distractor task, was part of a different experiment. The definitions

corresponding to the 48 targets and 48 distractors were displayed individually inrandom order. The subjects were instructed to type the first appropriate w ord

that came to mind for each definition. The next definition appeared immediately

after the subjects response to the previous one, or after 30 seconds in any case.

After the subjects had completed the general knowledge test, they were given

a free recall test. Subjects typed their recall on the computer keyboard,

continuing until 30 seconds had elapsed without additional recall.

Results

A preliminary analysis revealed no differences in results for the initial and

subsequently added subjects, so the two data sets were combined for the analysis

reported here.

Priming Scores. The dependent variable was the proportion of designated

terms (Remember targets, Forget targets, and distractors) that were produced in

response to their definitions on the general know ledge test. Mean proportions foreach group are shown in Table 2.

We performed a two-factor mixed analysis of variance on the proportions of

target words produced on the general knowledge test. More targets were given

with the list method than with the item method, F(1, 135) = 11.33, MSe = 0.03;

a nd m or e ta rge ts w er e g ive n t o d efi niti ons o f R em em be r w ords th an to

definitions of Forget words, F(1, 135) = 20.33, M Se = 0.007. The interaction was

also significant, F(1, 135) = 6.82. Simple tests established that directed

f or ge tt in g w a s s ig ni fi ca nt w ith t he ite m m e th od , F( 1 , 6 7 ) = 2 2 . 80 ,

M Se = 0.008, but not with the list method, F(1, 68) = 2.02, M Se = 0.007.

To determine whether priming had occurred, the proportions of Remember

and Forget targets provided were individually compared with the proportion of

T A B L E 2

Mean Proportions of Remember, Forget, and Distractor Terms Produced on the General

K n o w l e d g e T e s t i n E x p e r i m e n t 2

Word Type



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d is tr a ct o rs p r ov id e d . R e m e m b e r- ta r ge t p r im i n g w a s si g ni fic a n t, F(

135) = 239.40, M Se = 0.007. The interaction with method was significant, F(

135) = 5.20, reflecting greater priming with the list method than with the ite

method. Simple tests confirmed significant priming of Remember targets wi

both the list method, F(1, 68) = 159.18, M Se = 0.007, and the item method, F(

67) = 86.15, MSe = 0.007.The results of the Forget-target priming analysis were similar to those for th

Remember-target priming analysis. Both the effect of method, F(1, 135) = 8.2

M Se = 0.006, and the effect of instruction, F (1, 135) = 137.48, w ere significan

The significant interaction, F(1, 135) = 29.47, again reflected greater primin

with the list m ethod than with the item method. Simple tests confirmed th

Forget-target priming was significant for both the list method, F(1,68) = 149.5

M Se = 0.006, and the item method, F(1, 67) = 19.51. Thus, both Remember an

Forget words showed significant priming with both methods, but priming w

greater with the list method than with the item method.

F r ee R e c a ll . A tw o- fa cto r m i xe d m o de l a na ly sis of v arianc e w

performed on the proportions of Remember and Forget words produced durin

the final free recall test. Mean recall proportions for Remember and Forg

words were 0.14 and 0.11 with the list method, and 0.17 and 0.06 with the ite

method. The effect of instruction w as significant, F(1,134) = 60.53, M Se = 0.00

The interaction was also significant, F(1, 134) = 24.32, MSe = 0.005, reflectin

greater directed forgetting with the item method than with the list metho

Directed forgetting was significant with both the item method, F (1,67) = 75.5

M Se = 0.006, and the list method, F(1, 67) = 4.36, MSe = 0.005.

Discussion

Earlier we reported our failure to obtain item-method directed forgetting on aimplicit word association test (Basden et al., 1993, Experiments 1 & 2). W

attributed that null result to the low levels of priming that were observed. Th

experiment was designed to provide a more adequate test of directed forgettin

on a conceptual implicit test; i.e. one that showed adequate priming. We we

successful in that priming on the general knowledge test was significant for bo

Remember and Forget words and with both methods. There are several reaso

for greater priming in the present experiment. First, we used more targets, thu

permitting more observations. Second, the general know ledge items were relatively low frequency. Third, more redintegrative information is provided b



14/23

confirmed. Thus, i tem-method directed forgetting occurred on both the

conceptual test and on the explicit free recall test, but list-method directed

forgetting occurred only on the latter. These results are consistent with our

hypotheses that (a) Remember targets are more extensively processed than

Forget targets with the item method but not with the list method, and (b) tests of

implicit memory are sensitive to the effects of differential processing but not to those of retrieval inhibition. When subjects are given retrieval cues on an item-

by-item basis, suppression of the entire Forget list is unlikely to occur.

G ol di ng , L o ng a nd M a cl eo d ( 199 4) ha ve s ug ge st ed th at, as d ir ec te d

forgetting instructions may result in differential processing of Remember and

Forget words, the underlying basis for directed forgetting on implicit tests may

be differential levels of processing, much as w e have suggested here. However,

they did not distinguish between item- and list-method directed forgetting. If

differential processing underlies directed forgetting with both the list and item

method, then the list method should yield directed forgetting on implicit tests.

Not only should it occur, it should be greater than with the item method. In

mixed-list designs, investigators have found that the levels of processing effect

is larger when targets are blocked at presentation as in the list method rather than

random ly intermingled as in the item method (Challis & Brodbeck, 1992;

Thapar & Greene, 1994). The fact that this does not occur makes it clear that

differential processing of Remember and Forget items is not responsible for list-

method directed forgetting.

It could be argued that directed forgetting on item-method implicit tests

results from contamination of a supposedly pure test of automatic processing by

intentional retrieval. Toth, Reingold, & Jacoby (1994) recently applied the

process dissociation procedure to levels of processing findings. They reported

that conscious recollection accounted for the advantage of semantically

processed targets relative to nonsemantically processed targets on implicit

tests. Previously, item-method directed forgetting has been observed whensubjects were told to engage in intentional retrieval (Basden et al., 1993,

Experiment 3) or when the implicit test was not well camouflaged (MacLeod,

1989). Russo and Andrade (1995) recently applied the process dissociation

procedure to word fragment completion data that showed a directed forgetting

effect with the inclusion test procedure. Their estimate of the contribution of

conscious recollection was greater for Rem ember than for Forget targets. Their

results are consistent with our argument (Basden et al., 1993) that intentional

retrieval may contribute to directed forgetting on implicit tests. However, aninclusion test encourages subjects to consciously recollect the target items,



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taken to reduce the likelihood of contamination by intentional retrieval

s ugg e st ed b y R oe d ig er a nd M c D e rm o tt (1 99 3) . A pp l ic at io n o f p ro ce

dissociation procedures to properly conducted implicit tests may be gratuitou

In Experiment 3, we provided a further test of our contention that item

method directed forgetting involves differential processing but list-metho

directed forgetting does not. If Remember words are more extensively processe than Forget words with the item method but not with the list method, directe

forgetting should be absent when only the familiarity of Remember and Forg

items is assessed.


In this experiment we turned to the distinction between Know and Recolle

judgements presented by Tulving (1985) and developed extensively by Gardin(e.g. Gardiner, 1988; Gardiner & Java, 1993).

3Such judgements partitio

recognit ion performance into two components, one reflecting conscio

recollection (Recollect judgements), and the other reflecting familiarity (Kno

judgements). Recollect and Know judgements are obtained by asking subjects

indicate for each recognised item whether its actual occurrence in the study li

is remembered or it merely seems familiar.

Gardiner (1988, Experiment 1) observed a levels of processing effect wi

Recollect judgements but not with Know judgeme nts. Gardiner, Gawlik, an Richardson-Klavehn (1994) found i tem-method directed forgetting w

Recollect but not with Know judgements. In the present experiment w

included both methods of directed forgett ing. If, as we have propose

Remember and Forget targets are differentially processed with the item metho

but not the list m ethod, then directed forgetting should occur with Recolle

judgements for the item method but not for the list method. Neither method w

expected to yield directed forgetting with Know judgements.

M e t h o d .

Subjects, Materials, and Apparatus. We tested 40 students of the sam

description as in our earlier experiments. The word list and apparatus were th

same as in Experiment 2.

Design. The design w as a 2 2 factorial. Method (item or list) w

manipulated between subjects and instructions (Remember or Forget) wmanipulated within subjects. All subjects were given a recognition judgeme



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Procedure. The study instructions and method of presentation were the

same as in Experiment 2. List presentation was immediately followed by a

recognition judgement test. Instructions were drawn verbatim from Rajaram

(1993). To paraph rase, subjects were told to respond w ith ``N (Not Recognised),

if they did not remem ber having studied any given word; w ith ``K (Know ), if the

word appeared familiar, i.e. if they we re aware of the word in the context of theexperiment, but were unable to recollect any contextual information about that

word; and with ``R (R ecollect) if they consciously recollected having studied

that w ord. Each target or distractor wa s presented in uppercase letters, centred on

the monitor screen. Definitions of the available responses appeared below each

target and distractor. Subjects pressed ``N, ``K, or ``R, on the computer

keyboard for each word. Each new word was presented immediately after a

response to the previous word, or after 30 seconds in any case.

Results

The mean proportions of Remember and Forget words judged as Recollect and

Know are shown in Table 3, along with Recollect and Know judgements for

distractors.

A mixed two-factor analysis of variance was performed on the Recollect

judgements for Remember and Forget targets. I t produced a s ignificant

interaction between method and instruction, F(1, 38) = 11.32, M Se = 0.015.Subsequent simple tests showed directed forgetting with the item method, F(1,

19) = 26.04, M Se = 0.014, but not with the list m ethod, F


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significant, F(1, 38) = 11.54. The difference between Forget and Distract

w ord s w as s ig nifi cant no t o nly w ith th e lis t m e tho d, F(1, 19) = 235.3

M Se = 0.019, but also with the item method, F(1, 19) = 69.17, M Se = 0.028. Th

difference between Forget and Distractor words was greater with the list metho

than with the item methods.

Discussion

In earlier reports (see Basden et al., 1993; Basden et al., 1994), we demonstrate

that directed forgetting occurs in recognition with the item method but not wi

the list method when overall performance is examined. This experime

c onf ir m s th is c onc lu si on , a nd de m o ns tr at es t ha t i t a pp lie s t o R e co ll e

judgements and not to Know judgements. This dissociation supports o

hypothesis that the processes underlying directed forgetting differ for the twmethods. The difference in correct Recollect judgements between Forget an

Distractor items was greater with the list method than with the item method, b

the corresponding difference between Remember and Distractor items was th

same with the two methods. Forget words appear to receive less extensi

processing than Remember words with the item method, but Remember an

Forget words appear to receive equivalent processing with the list method.

Our results with the item method replicated those of Gardiner et al. (1994

They varied the delay of the Forget or Remember cue and found that increasede lay w as a ss oc iate d w it h a n inc rea se in K now judge m en ts fo r item

accompanied by either cue. Increased cue delay was associated with an increa

in Recollect judgements for Remember targets but not for Forget targets. The

interpretation, with which we concur, was that maintenance rehearsal influenc

familiarity, and hence, Know judgements. There is no corresponding increase

Recollect judgements with delay, because elaborative rehearsal is necessary

increase conscious recollection.

The present results are consistent with evidence from Experiment 1 th

subjects retain greater contextual information for Remember than for Forg

words with the item method but not with the list method. Subjects were mo

accurate in providing serial position information for Rem ember than for Forg

targets with the item method than w ith the list method. The ability to rememb

the serial position of targets reflects greater conscious recollection for the

context. Similarly, Recollect judgem ents reflected memory for the specif

context in which particular words occurred. This is consistent with our argume

that the item method is more encouraging to differential processing than is th

list method



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presentation of items from a single category, having subjects study pictures or

form images increased directed forgetting m ore with the item method than with

the list method. In Experiment 2, directed forgetting occurred with the item

method but not with the list method when responses to general knowledge

questions were analysed. In Experiment 3, Recollect judgements showed

directed forgetting w ith the item method but not with the list method. Thus, the present research further confirms that the processes underlying item- and list-

method directed forgetting differ.

The present results should be of interest to those who study inhibitory

mechanisms in recall. Although directed forgetting was greater with the item

method than with the list method when pictures and images (which encourage

item-specific processing) w ere studied, it was equivalent with the two methods

when words alone (which encourage relational processing) were studied. Thus,

for materials that encourage relational processing, the retrieval inhibition

process may yield substantial directed forgetting. Perhaps because directed

forgetting tends to be more reliably obtained with the item method than with

the list method (e.g. Basden et al., 1993), many recent experiments have been

conducted with the item method, particularly when implicit tests were used

(e.g. Gardiner et al., 1994; Golding et al., 1994; MacLeod, 1989; Russo &

Andrade, 1995). This seems an unfortunate choice because, by our account, it

is the list method that reflects subjects ability to lose or regain access to

previously stored information. Understanding of retrieval inhibition in the

context of directed forgetting may facilitate our understanding of retrieval

inhibition in more exotic contexts, such as recovery of repressed memories

(e.g. Cloitre et al., 1995).

Interest in inhibitory mechanisms in memory has enjoyed a recent resurgence

and new theoretical approaches have emerged. Zacks, Radvansky, and Hasher

(1995) presented an approach that distinguishes betw een two different inhibitory

mechanisms in directed forgetting. The first involves retrieval inhibition; thesecond involves the stopping of rehearsal following presentation of a Forget cue.

The latter mechanism is one that prevents information from entering working

memory (see Hasher & Zacks, 1988). According to this formulation older

subjects are deficient in inhibitory processing. Target information that is

designated as to-be-forgotten may not be successfully inhibited, either because

subjects cannot successfully inhibit retrieval of previously stored information or

because items designated as to-be-forgotten are processed just as effectively as

items that are not designated as to-be-forgotten. Experiments conducted byZacks et al. showed that older subjects were less successful in meeting the



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It has been proposed (Geiselman et al., 1983, p.63) that directed forgettin

can be accounted for in terms of a mechanism by which ``an F cue serves

initiate a process that inhibits the accessibility of a space in time in episod

memory. However, when we measured memory for context by asking subjec

to provide serial position information for the Forget items they had recalled, w

found that experimental subjects were as accurate in their judgements as wecontrol subjects. As our measure of contextual memory is less likely to hav

been contaminated by attributional errors than is the measure used by Geiselma

et al., we conclude that there is little evidence to support an explanation

retrieval inhibition in directed forgetting that relies on loss of contextu

information.

In conclusion, our results clearly show the desirability of distinguishin

between the two methods of directed forgetting, as initially proposed by Bjor

(1972). Item-method directed forgetting relies on processing distinctive featur

of individual targets and influences retention of Remember and Forget targets

a manner analogous to levels of processing procedures. On the other hand, lis

method directed forgetting encourages relational processing and appears

differentially influence performance only on a free recall test, a test that

sensitive to relational processing. When subjects are provided with retriev

information in the form of word associates, word fragments, or copy cue

directed forgetting with the list method disappears. Only when subjects a

required to rely on their own organisational system is list-method directe

forgetting manifested. These observations support the idea that list-metho

directed forgetting is dependent on organisational (relational) processin

whereas item-method directed forgetting is dependent on distinctive (item

specific) processing.

Manuscript received 25 May 19

Manuscript accepted 11 December 19

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