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Journal at Experimental Psychology1971 , Vol. 90, No. 2 , 227-234

FACILITATION IN R EC O G NI ZI NG P A I R S OF WORDS:

E VI D E N CE OF A DE P END ENC E B ETW EEN R ETR I EV A L OPERATIONS 1

D A V I D E. M E Y E R

2

ANDBell Telephone Laboratories, Murray Hill, New Jersey

ROGER W. SCHVANEVELDTUniversity of Colorado

Two experiments are reported in which 5s were presented tw o strings of letterssimultaneously, with on e string displayed v isua lly above th e other. In Exp. I,5s responded "yes" if both strings were words, otherw ise respond ing "no."In Exp. I I , 5s responded "same" if the two strings were either both wordsor both non wo rds, otherw ise responding "diff eren t." "Yes" responses an d"same" responses were fa ster fo r pairs of com mon ly associated words than forpairs of unassociated words. "Same" responses were slowest for pairs of non-words. "No" responses were faster when the top string in the display was anonword, whereas "different" responses were faste r when the top string was aword. The results of both experim ents sup port a retrieval mod el involving adependence between separate successive decisions about whether each of thetw o strings is a word. Possible mec hanisms that underlie this dependence arediscussed.

Several investigators recently havestudied how 5s decide that a string ofletters is a word (Landauer & Freedman,19 68; Meyer & Ellis, 1 9 7 0; Rubenstein,Garfield, & Mil l ikan , 1970) . They typi-cally have presented a single string on atrial, measuring reaction time (RT) of the

lexical decision as a funct ion of the string'smeaning, familiarity, etc. In one suchexperiment, RT varied inversely withword frequency (Rubenstein et al., 1970) .When word frequency was controlled,lexical decisions were faster fo r homographs(i.e., words having two or more meanings)than for nonhomographs. To explainthese results, Rubenstein et al. proposedthat word frequency affects th e order ofexamining stored words in long-term mem-ory and that more replicas of homographsthan of nonhomographs are stored in long-term memory.

In another experiment, Meyer and Ellis(1970) measured both the time taken to

1This paper is a report from work begun in -dependently by the two authors at Bell TelephoneLaboratories and the State University of New Yorkat Stony Brook, respectively. W e tha nk S. Stern-berg, T. K. Landauer, and Alexander Pollatsek for

their helpful comments, A. S. Coriell fo r preparingth e apparatus, and G. Ellis and B. K un z fo r run-ning 5s.

2 Requests for reprints shou ld be sent to D avid E.M eyer, Bell Telephone Laboratories, 600 MountainAvenue, M u r r a y Hill, New Jersey 07974 .

decide that a string of letters (e.g., HOUSE)is a word and the time taken to decidethat it belongs to a prespecified semanticcategory. When the category was rela-tively small (e.g., BUILDINGS), th e lattertype of semantic decision was significantlyfaster than th e former lexical decision.

However, when the category was relativelylarge (e.g., STRUCTURES), th e semanticdecision was slightly slower than the lexicaldecision. To explain these and otherresults , Meyer and Ellis suggested thatthe semantic decision may have involvedsearching through stored words in the

semantic category and that the lexicaldecision did not entail a search of this kindamong the set of all words in memory.

The present paper provides further dataabout th e effect of meaning on lexical de-cisions. To deal with this problem, we

have extended the lexical-decision task bysimultaneously presenting two strings ofletters for 5 to judge. The stimulus may

involve either a pair of words, a pair of

nonwords, or a word and a nonword. In

one task, 5is instructed to respond "yes"i f both strings are words, and otherwise to

respond "no." In a second task, the

instructions require 5 to respond "same"

i f the two strings are either both words or

both nonwords, and otherwise to respond"different." In each task, RT for pairs of

2 27



228 DAVID E. MEYER AND ROGER W . SCHVANEVELDT

words is measured as a funct ion of the asso-

ciative relation between the two words.

The two tasks together are designed togive information about the nature and theinvariance of underlying retrieval opera-

tions. One of their advantages is that therelation between words can be varied whilekeeping the overt response constant. We

reasoned that the response might involve

separate, successive decisions about each

of the two words. By varying the degree

of association between the words, we then

hoped it would be possible to test for a

dependence between memory-accessing

components of the two decisions. Experi-ment I reports the results of such variationin the context of the yes-no task.

EXPERIMENT IMethod

Subjects.—The 5s were 1 2 high school studentswh o served as paid volunteers.

Stimuli.—The following test stimuli were used:48 pairs of associated words, e.g., B R E A D - B U T T E R

an d N U R S E - D O C T O R , selected from th e ConnecticutFree Associational Norms (Bousfield, Cohen, &Whitmarsh , 1961) ; 48 pairs of unassociated words,

e.g., B R E A D - D O C T O R and N U R S E - B U T T E R , formed byrandomly interchanging th e response terms be-tween the 48 pairs of associated words so that therewere no obvious associations wi thin the res ult ingpairs; 48 pairs of nonwords; and 9 6 pairs involvin ga word and a nonword. Within each pair of asso-ciated words, th e second member was either th efirst or second most frequent free associate given inresponse to the first mem ber. W ithin each pair ofunassociated words, th e second member was neverthe first or second most frequent free associate of thefirst mem ber. The median length of strings in thepairs of associated words and pairs of unassociated

words was 5 letters an d ranged from 3 to 7 letters;the median word frequ ency was 59 per million, an dranged from 1 ,7 47 to less than 1 per million (Kucera& Francis, 1967). A separate set of 96 words wasused for the pairs involving a word and a nonword.These words were similar to the associated wordsin terms of frequency, length, an d semantic classifi-cation. Non word s were constructed from commonwords, e.g., M A R K , replacing at least on e letter withano the r letter. Vow els were used to replace vowels,and consonants were used to replace consonants.Th e resulting strings of letters, e.g., M A R B , werepronounceable an d were equal in average length to

the words paired with them. A ma jority of thenonwords differed by only a single letter from someEnglish word, and the differences were no t syste-matically associated with any one letter position.

In addition to the test stimuli , 24 pairs of words,8 pairs of nonwords, and 16 pairs involving a word

an d a nonword were constructed as practice stimuli.Degree of association was not varied systematicallyamong the pairs of practice words.

Apparatus.—The stimuli were generated on aStromberg Carlson SC4060 graphics system, photo-graphed on 16-mm. movie film and presented on a

rear-projection screen by a Perceptual DevelopmentLaboratories' Mark II I Perceptoscope. The 5sresponded via a panel having finger keys for theright and left hand s. Reaction time was measuredto the nearest millisecond by count ing th e cyclesof a 1,000-Hz. oscillator.

Procedure and design.—The 5s were run in-dividually during one session involving a series ofdiscrete RT trials. The 5 was seated in front of thedarkened screen throughout th e session. At thebeginning of each trial, th e word R E A D Y was pre-sented briefly as a warning signal on the screen.A small fixation box, which subtended approximate

visual angles of 3°40' horizontally and 1°50' verti-cally, then appeared dur ing a 1-sec. foreperiod.Following th e foreperiod, th e st imulus was dis-played horizontally in (white) capital letters in themiddle of the box, with one string of letters centeredabove th e other. I f both strings were words, 5pressed a key labeled "yes" with his right indexfinger, otherwise pressing a "no" key with the leftindex finger. Reaction time was measured fromstimulus-onset to the response, which terminated thestimulus display. D urin g an appro xima te 2-sec.interval when the screen was blank after each trial,5 was informed of w he t he r his response had been

correct.The session lasted about 45 min. and included ashort instruct ion period and two blocks of 24practice trials, followed by four blocks of 24 testtrials. After each block, 5 was informed of his meanRT and total number of errors for the block, whilehe rested fo r abou t 2 mi n. This feedback was in-tended to encourage fast an d accurate responses.To fur the r motivate good performance, 5 was given$3 at the start of the session and then penalized I j ifor each .1 sec. in mean RT on each trial block, an d3 f i fo r each error. Wh atever money remained atthe end of the session served as 5's payment for the

experiment.The entire set of practice stimu li was presentedduring the two practice trial blocks. D uri ng thetest trial blocks, each 5 was shown 1 6 pairs of non-words, 32 pairs inv olving a w ord and a nonword,24 pairs of associated words, and 24 pairs of un-associated words from th e total set of test st imuli .Half of the practice trials and test trials therefore re -quired "yes" responses. Presentation of the teststimuli was balanced, so that each individual s t imu-lus of a given type was presented equally often across5s; e.g., each pair of associated words was presenteda total of six times ac ross 5s, while each pair of non-

words was presented a total of four times. No 5saw any string of letters more than once. In dis-playing both the pairs of associated words and thepairs of unassociated words, the top string (e.g.,B R E A D ) was always a stimu lus term from the normsof Bousfield et al. (1961), while the bottom string



FACILITATION IN WORD RECOGNITION 229

TABLE 1

MEAN REACTION TIMES (RTs) OF CORRECT RESPONSES AND MEAN PERCENT ERRORSIN T H E YES-NO T A S K

Type of stimulus pair

Top string

wordword

wordnonwordnonword

Bottom string

associated wordunassociated word

nonwordwordnonword

Correct response

yesyes

nonono

Proportion

of trials

.25

.25

.167

.167

.167

Mean RT

(msec.)

8559 40

1,0879 04884

Mean %

errors

6.38.7

27.67 .82.6

(e.g. BUTTER) was always a response term. For

the stimuli containing at least one nonword, each

string was assigned equally often across 5s to thetop and bottom display positions. There were thusfive types of stimuli, which are listed in Table 1 to-gether with their relative frequencies of occurrence.Relative frequencies of these types were balancedwithin trial blocks to equal their relative frequenciesin the total set of test stimuli. The above set ofconstraints on stimulus presentation w as used toconstruct six lists of 96 test stimuli each. Subjectto these constraints, two random orders of stimuluspresentation were obtained for each list. Each S

was then randomly assigned one of the lists presentedin one of the orders, so that each list in each order

was used for exactly one 5.

Results and Discussion

Reaction time and error data from thetest trials were subjected to Ss X Treat-ments analyses of variance (Winer, 1962).Prior to analysis, an arc-sine transformationwas applied to each 5's error rates. Thereported standard errors and F ratios werecomputed using error terms derived fromthe 5s X

Treatments interactions.Table 1 summarizes mean RTs of correctresponses and mean percent errors averagedover 5s. "Yes" responses averaged 85 ± 19msec, faster for pairs of associated wordsthan for pairs of unassociated words, F (1 ,1 1 ) = 20.6, p < .001. "No" responses to

pairs involving a word and a nonwordaveraged 183 ± 14 msec, faster when the

nonword was displayed above th e word, F(1 , 11) = 1 7 1 . 7 , £ < .001. "No" responses

for pairs of nonwords were not signif-icantly faster (20 ± 14 msec.) than "no"responses for pairs where a nonword wasdisplayed above a word, F ( 1 , 1 1 ) = 2.0,p > .10.

The error rates fo r pairs of unassociatedwords versus pairs of associated words didnot differ significantly, F (1 , 1 1 ) = 2.1,p > .10. The error rate for pairs involvinga word and a nonword was significantlygreater when th e word was displayed aboveth e nonword, F ( 1 , 1 1 ) = 18.9, p < .005.The error rate fo r pairs of nonwords wassignificantly less than that for pairs wherea nonword was displayed above a word,7 7 ( 1 , 1 1 ) = 5.5, p < .05.

Error rates were relatively lo w except for

pairs where a word was displayed above anonword. A possible reason fo r this ex-ception is considered in later discussion.The pattern of errors suggests that aspeed-accuracy trade-off did not cause th eobserved differences in mean RTs; i.e.,mean error rates tended to correlate posi-tively with mean RTs.

The results of Exp, I suggest that degreeof association is a powerful factor affectinglexical decisions in the yes-no task. For

example, th e effect of association appears tobe on the order of two or three times largerthan th e average effect of homographyreported by Rubenstein et al. ( 1 9 70) .This effect of association occurred con-sistently across 5s, and 11 of the 12 5sshowed it in excess of 30 msec. In Exp. II ,another group of 5s performed the same-different task to fu r the r study the gener-ali ty of the effect.

EXPERIMENT IIMethod

Subjects.—The 5s were 12 high school studentswho served as paid volunteers. They had not beenin Exp. I, but were drawn from the same population.



230 DAVID E.MEYER AND ROGER W. SCHVANEVELDT

TABLE 2

M E A N R E A C T I O N TIMES (RTs) O F C O R R E C T R E S P O N S E S A N D M E A N P E R C E N T E R R O R S I N T H ESAME-DIFFERENT TASK

Type of stimulus pair

Top string

wordwordnonword

wordnonword

Bottom string

associated wordunassociated wordnonword

nonwordword

Correct response

samesamesame

differentdifferent

Proportionof trials

.125

.125

.25

.25

.25

Mean RT

(msec.)

1,0551 ,1721,357

1,3181,386

Mean %

errors

2.48.78.9

11.612.0

Stimuli.—The same set of test stimuli was usedas in Exp. I. In addition, 1 6 pairs of words, 1 6pairs of nonwords, and 32 pairs involving a word and

a nonword were constructed as practice stimuli.Most of these practice stimuli also had been usedin Exp. I.

Apparatus.—The same apparatu s was used as inExp. I.

Procedure and design.—The procedure and de-sign were similar to those used in Exp. I, except fo rth e following modifications. The 5 pressed a "same"key with his right index finger if the stimulus in-volved either tw o words or two nonwords, other-wise pressing a "different" key with th e left indexfinger. The com plete session lasted about 1 hr. andincluded a short instruction period, two blocks of

32 practice trials, and six blocks of 32 test trials.Tw o lists of 192 test stimuli each were constructed.For each list, two random orders of presentationwere obtained, subject to constraints like those usedin Exp. I. Each of these List X Order combina-tions was then used for three of the 5s. During th etest trial blocks, each 5 was presented 48 pairs ofnonwords, 9 6 pairs involving a word and a nonword,24 pairs of associated words, and 24 pairs of un-associated words from the total set of test stimuli.Half of the trials therefore required "same" re-sponses. Because th e same-different task was some-wha t more difficult than the yes-no task, each 5 was

given $3.50 at the start of the session.

Results

The results were analyzed in the same

way as Exp. I. Table 2 summarizes mean

RTs of correct responses and mean percent

errors averaged over 5s. "Same" responsesaveraged 117 ± 18 msec, faster for pairs

of associated words than fo r pairs ofunassociated words, F (1, 11) = 42.6,

p < .001. "Same" responses averaged185± 29 msec, slower for pairs of nonwords

than for pairs of unassociated words,

F (1, 11) = 40.7, p < .001. "Different"responses averaged 68 ± 25 msec, faster

when the word was displayed above the

nonword, F (1, 11) = 7.3, p < .025.

The error rate for pairs of associated

words was significantly less than the error

rate for unassociated words, F (1, 11) =

16.6, p < .01. The difference between error

rates for pairs of unassociated words andpairs of nonwords was not significant,F (1, 11) < 1.0. For pairs involving a

word and a nonword, the error rate did not

depend significantly on whether the word

was displayed above or below the non-

word , F (1,11) < 1.0.

A comparison of mean RTs in the yes-notask (Exp. I) versus mean RTs in the same-different task revealed the following: "Yes"

responses to pairs of words averaged 216

± 68msec, faster than "same" responses topairs of words, F (1, 22) = 10.2, p < .01.

The effect of association on "same" re-

sponses to pairs of words did not differsignificantly from its effect on "yes" re-sponses, F (1, 22) = 1.4, p > .20. "No"

responses to pairs involving a word and a

nonword averaged 357 ± 74 msec, fasterthan "different" responses, F (1, 22) =23.6, p < .001. For pairs involving a wordand a nonword, the effect of the word's

display position on RT interacted sig-

nif icant ly with th e task, F (1 , 22) = 76.4,

p < .001.

DISCUSSION

As a f ramework for explaining ou r results, w etentatively propose a model involving tw o

separate, successive decisions. According tothis model , st imulus processing typically be-gins with the top string of letters in the dis-play. The first decision is whether the topstring is a word and the second is whether th e




bottom string is a word. If the first decisionis negative in the yes-no task, w e presumethat processing terminates without th e seconddecision and S responds "no." Otherwise, bothdecisions are made and 5's response cor-

responds to the second decision's outcome.It is assumed that in the same-different task,both decisions are normally made regardlessof th e outcome of the first. After both de-cisions, their outcomes are compared. If theoutcomes match, S responds "same"; other-wise, he responds "different."

Now let us consider the RTs and error ratesof yes-no responses. The serial-decision modelexplains why "no" responses are faster whenthe top string is a nonword . This happens be-cause only the first decision is made, whereas

both decisions are made when the top stringis a word. The model also ex plains w hy "no"responses are about equally fast for pairswhere only the top string is a nonword, ascompared to pairs where both strings are non-words; i.e. , fo r either kind of pair, only th efirst decision is ordinarily made. An oc-casional reversal in the order of s t imulus pro-cessing, beg innin g w ith th e bottom ra therthan top str ing, might account for the slightlyfaster responses to pairs of nonwords.

The relatively high error rate fo r pairs in -

volving a word above a nonword suggests thatprocesses prec eding "yes" responses sometim esterminate prematurely after the first decision.In these cases, 5 may feel that discovering aword in the top position is sufficient evidencefo r responding "yes," without making th esecond decision. This beha vior would not betoo unreasonable, given th e relative f requen-cies of the various types of stimuli. Such pre-mature terminat ion of stimulus processing,together with an occasional reversal in theprocessing order, would also explain why "no"responses were most accurate fo r pairs ofnonwords.

The RTs from th e same-different task donot provide direct evidence for testing the pro-posed serial-decision model because both lexi-

cal decisions are assumed to be made before al lsame-different responses. Ho w ever, the rela-tive invariance of the association effect acrossth e yes-no and same-different tasks suggeststhat similar processes occur in both tasks. Anadditional operation, which compares the out-comes of the two lexical decisions for a match,would explain w hy responses were somewhatslower in the same-different task than in theyes-no task.

Several factors in the present experimentsmay have induced 5s to process th e strings ofletters serially. For example, Ss were en-couraged to perform with high accuracy andwere allowed to move their eyes in examin ing

th e stim ulu s display. Unde r other circ um -stances, e.g., with brief stimulus presentationa n d / o r a more relaxed error criterion, 5s m ig h tprocess two or mo re words in parallel.

If th e serial-decision model is valid for thepresent experiments , then one can use theyes-no data to estimate th e t ime taken in de-ciding that a string of letters is a word . Inpart icu lar , let rnw represent the mean RTto respond "no" to a nonword displayed abov ea word. Let Tvn represent the mean RT torespond "no" to a nonword displayed below a

word. Then with certain assumptions (cf.Sternberg, 1969) , th e difference Twn — Tnw isa measure of the mean t ime to decide that th etop string is a word. From the results of Exp.I, an est imate of this difference is 1 83 ± 1 4msec. An occasional reversal in the order ofs t imulus processing would make this differencean underest imate of the t rue mean.

One can also estimate approximately howm u c h t ime is required to compare the ou tcomesof the two decisions before same-different re -sponses. For example, suppose the mean RT of

"yes" responses (E xp. I) is sub trac ted from th emean RT of "same" responses to pairs of words(Exp. II). Then with certain assumptions,th e difference of 21 6 ± 68 msec, is an estimateof the comparison time when the two decisionsmatch . On the other hand, suppose th e meanRT of "no" responses to a word displayedabove a nonword is subtracted from th e corre-sponding mean RT for "different" responses.Then th e difference of 231 ± 7 6 msec, is anestimate of the comparison time when the twodecisions do not match.

What kind of operation occurs dur ing eachof the two proposed decisions? One possi-bility is that visual and/or accoustic featuresof a string of letters are used to compute an"address" in memory (Norman, 1969 ; Schiffrin& Atkinson, 19 69) . A lexical decision abou t astring might then involve accessing and check-ing some part of the contents of the string'scompu ted mem ory locat ion (cf . Rub ensteinet al., 1970). Given this model, memorylocations would be computed for both words

and nonwords , a l thoug h the contents of non-word locations might differ qual i ta t ively f rom

those of wo rd loc ation s. In essence, we aretherefore suggesting that both words and non-



23 2 DAVID E. MEYER AND ROGER W. SCHVANEVELDT

words may have locations "reserved" for themin long-term memory.

The effect of association on RT does notnecessarily imply that th e meaning of a wordis retrieved to make a lexical decision. To

understand wh y, consider th e following elab-oration of the serial-decision model, whichm ay explain th e effect. First, suppose thatlong-term memory is organized semantically,i.e., that there is a s t ruc ture in w h i c h the lo-cations of two associated words are closerthan those of two unassociated word s. Evi-dence from other studies of semantic mem orysuggests that this assumption is not totallyunreasonable (Collins &Quill ian, 1 9 6 9 ; Meyer ,1970). Let LI and La denote th e memory lo-cations examined in the first and second de-

cisions, respectively. Second, suppose thatth e t ime taken to make th e second decisiondepends on where La is relative to LI. Inpart icu lar , let us assume that th e t ime takenaccessing inf or m at io n for the second decisionvaries directly with th e "distance" betweenLI and La. Then responses to pairs of asso-ciated words would be faster than those topairs of unassociated words. This followsbecause the proximity of associated words inth e memory structure permits faster accessingof in format ion for the second decision. The

argument holds even if the accessed informa-tion is (a) sufficient only to determine whethera string is a word and (&) does no t includeaspects of its meaning.

If our second assumption above is correct,then any retrieval operation Ra that is re-quired sufficiently soon after another operationRI will generally depend on RI. This w ou l dmean that human long- te rm memory , l ikemany bulk-storage devices, lacks the proper tyknown in the computer l i terature as randomaccess (cf. Mc Cormick, 1959, p. 103). Re-

cent ly , Meyer (1971) has collected data inother tasks that are consistent with this notion.

There are several ways in which this de-pendence between retrieval operations mightbe realized. One possibility is that retrievinginformation f rom a particular memory locationproduces a passive "spread of excitation" toothe r nearby locations , fa cil i ta t ing later re-trieval from them (Collins & Quill ian, 1 9 7 0 ;Warren, 1970) . A second speculative possi-bility is that retrieving information from

long-term memory is l ike retrieving informa-

tion f rom a magnetic tape or disk. In thislat ter model , facil i tat ion of retrieval wouldoccur because (a) information can be "read

out" of only one location during any given

instant , (b ) t ime is required to "shift" readoutfrom one location to another, and (c) shi f t ingtime increases with th e distance betweenlocations.

The present data do not provide a direct

test between this location-shifting model andth e spreading-excitation model. However, th elocation-shifting model may explain one resultthat is difficult to account for in terms ofspreading excitation. In particular , considerth e following argument abou t the f inding that"different" responses were faster when a wordwas displayed above a nonword. W e pre-viously have argued that processing normallybegins with a decision about the top string andthen proceeds to a decision about the bottomone. Let us now assume that memory is or-

ganized by familiarity as well as by meaning,wi th f requent ly examined locat ions in one"sector" and inf requent ly examined locat ionsin another sector. Recently , Swanson andWickens (1970) have collected data suppor t inga similar assumption that Oldfield (1966) hasmade. Suppose f u r the r that before each trial ,a location is preselected in the sector wherefamiliar words are stored, which would beoptimal u nd er most circumstances (cf. Old-field, 1966). Then th e response to a w orddisplayed above a nonword would require

only one major shif t between memory loca-tions in the familiar and unfami l i a r sectors.This shift would occur after the first decision,changing readout from th e famil iar to theunfamiliar sector.

3In contrast, the response

to a nonword displayed above a word wouldrequire two major shifts, i.e., one from th efamiliar to the unfamil iar sector before thefirst decision and one re tu rn ing to the familiarsector before th e second decision. This wouldmake "different" responses slower when th enonword is displayed above the word. More-

over, th e assumption that th e starting locationis in the familiar sector fits with the findingthat lexical decisions are generally faster forfamiliar than for unfamil iar words (Ruben-stein et al . , 1970); i .e. , a major shift betweenlocations is required to access potential in -format ion about an unfamil iar word, whereassuch a shif t would not be required for afamiliar one.

3 Here we are invoking our earlier proposal thatboth words and nonwords may have locations re-

served for them in memory. We are assuming thatfrom the viewpoint of retrieval, a nonword that issimilar to English may be treated as a very un-familiar word whose location is examined infre-quently.




The effect of association on "same" responsesto pairs of words (Exp. II) is also relevant toa recent finding by Schaeffer and Wallace( 1 9 6 9 ) . In t he i r s t udy , 5s were presentedwith a pair of w ords and requ ired to respond

"same" i f both words belonged to the semanticca t egory LIVING THINGS or if both be-longed to the c a t e g o r y N O N L I V I N GTHINGS. Otherwise , 5s responded "dif-fere nt ." Reaction t ime of "same" responsesvaried inversely with th e semantic similari tyof th e words in the pair; e.g., "same" responsesto a st imulus l ike T U L I P - P A N S Y were fastert han "same" responses to a s t imulus l i keTULIP-ZEBRA. In contrast, Schaeffer andWallace (1970) fou nd that the RT of "dif-ferent" responses varied direct ly with semantic

s imila r i ty . They at t r ibuted the effects of simi-lari ty on both "same" and "di fferent" re-

sponses to a process that compares the m e a n -ings of the w o r d s in a s t i m u l u s .

Th e effects of association in Exp. I and IIpossibly co u ld have been caused by s u ch acomparison process, rather than by the re-

t r ieval me ch anis ms discussed above. How -ever, if the "meaning" of a word is representedby the semantic categories to which it belongs,then there seemingly is a difference betweenth e same-di fferent task of Exp. II and theone studied by Schaeffer and Wallace ( 1 969 ,1 9 7 0 ) . Logical ly , Exp. II did not requi re 5s tocompare th e mean ings of the i tems in a s t imu-lu s ; i.e., 5s did not have to jud ge wh e the r bo thstrings belonged to the same semantic category,e .g ., L IV IN G THIN GS . Ins t ead , Exp . II onlyrequi red compar ing th e i tems' lexical status.Moreover , a compar ison of meanings wouldhave been imp ossible for those pairs involv-ing a t least one nonword , s ince th e n o n w o r dwould have n o mean ing in the u sua l sense.One m igh t t he re fo re a rgue that 5s did notco m p a r e th e meanings of i t e m s in Exp. II.T h e a r g u m e n t is reinforced by the fac t thatExp. I (yes-no task) , w hic h logically did notr equ i re compar ing th e strings in any w a y ,p roduced an effect of associat ion l ike the oneobserved in Exp. II .

O u r reasoning suggests , f u r t h e r m o r e , thatth e findings of Schaeffer and Wallace (1969 ,1 970 ) may not have resulted solely from a com-parison of word meanings. Ra ther , their find-ings could have been caused at least in part by

a retrieval process like the one we have pro-posed. This poin t is suppor ted by the magni-tudes of the s imi l a r i t y effects they observed,w h i c h averaged 1 7 6 msec, fo r faci l i ta t ing"same" responses (Schaeffer & Wallace , 1969)

and 120 msec, for inhibit ing "different" re-sponses (Schaeffer & Wallace , 1970) . In par-t icular , consider th e following detailed argu-ment . Suppose that j u d g m e n t s in their taskinvolved two components: an ini t ial retrieval

process similar to the one we have proposed,which m i g h t be necessary to access word mean-ings, and a process that compares word mean-ings (cf. Sch aeffer & Wallace , 1 9 7 0). Supposef u r t h e r that ou r exper iments requi red only th efirst process. One might then expect thatwhenever both of these processes are used in"same" j ud gm ent s , t hey w ould bo th be fa -cilitated by semant ic s imi lar i ty . However ,w h e n they are used in "di fferent" judgments ,similari ty wo uld inh ibit the com parison processwhile still fa c ilit at in g the retrieval process.

This would expla in why the effect of associa-tion on "same" responses in Exp. II ( 1 1 7msec.) w as less than th e effect of s imi lar i ty on"same" responses in the s tudy by Schaeffer andWallace (1 9 69 ) . M oreover , i t w ould a lsoexplain their finding that semant ic s imi lar i tyinhibi ted "different" responses less than it

facilita ted "same" responses . Unfor tunate ly ,the a r g u m e n t is par t ia l ly weakened by at

least one fact ; i .e . , their results for "same"versus "different" responses were obtained inseparate expe r iment s us ing somewha t different

semantic categories and test words.Regardless of whether spreading exci ta t ion ,

location shi f t ing , compar ison of meanings , orsome other process is i nvo lved , th e effects ofassociation appear limited neither to semanticdecisions nor to same-different j u d g m e n t s .At present we do not have ways to test all the

possible explanations of these effects. H o w -ever , procedures l ike th e ones w e have de-scribed may provide a way to study relat ionsbetween retrieval operat ions that are tem-poral ly con t iguou s. We may th erefore be ableto learn more about both the na ture of in-dividual memory processes and how theyaffect one ano the r .

REFERENCES

B O U S F I E L D , W. A., C O H E N , B. H., W H I T M A R S H , G.A., & K I N C A I D , W. D. The Connecticut free asso-ciational norms. (Tech. Rep. No. 35) Storrs,Conn.: University of Connecticut, 19 61.

C O L L I N S , A. M., & Q U I L L I A N , M. R. Retrieval timefrom semantic memory. Journal of Verbal Learn-

ing and Verbal Behavior, 1969 , 8, 240-247.COLLINS, A. M ., & Q U I L L I A N , M. R. Facilitatingretrieval from semantic memory: Th e effect ofrepeating par t of an inference. In A. F. Sanders(Ed.), Attention and performance III. Amster-

d a m : North-Holland Publishing Company, 1970 .



234 DAVID E. M E Y E R AND ROGER W. SCHVANEVELDT

KUCERA, H., & F R A N C I S , W. N. Computationalanalysis of present-day American English. Provi-dence, R. I. : Brow n University Press, 196 7 .

L A N D A U E R , T. K., & F R E E D M A N , J. L. Informationretrieval from long-term memory : Category sizeand recognition time. Journal of Verbal Learning

and Verbal Behavior, 1968, 7 , 291-295.McCoRMicK, E. M. Digital computer primer. New

York: McGraw-Hill , 1959.M E Y E R , D. E. On the representation and retrieval

of stored semantic information. Cognitive Psy-chology, 1970, 1, 242-300.

M E Y E R , D. E. Dual memory-search of related andunrelated semantic categories. Paper presentedat the meeting of the Eastern Psychological Asso-ciation, New York, April 1971 .

M E Y E R , D . E., & ELLIS, G . B. Parallel processes inword recognition. Paper presented at the meetingof the Psychonomic Society, San Antonio, No-

vember 19 70.N O R M A N , D. A. Comm ents on the information

structure of memory. In A. F. Sanders (Ed.),Attention and performance HI. Amsterdam:North-Holland Publishing Company, 1970.

O L D F I E L D , R. C. Things, words and the brain.Quarterly Journal of Experimental Psychology,1966, 18, 340-353.

RUBENSTEIN, H., GARFIELD, L., &MlLLIKAN, J. A.

Homographic entries in the internal lexicon.Journal of Verbal Learning and Verbal Behavior,1 9 7 0 , 9 , 487-494.

S C H A E F F E R , B., & W A L L A C E , R. Semantic similarityand the comparison of word meanings. Journal

o f Experimental Psychology, 1969,82, 343-346.S C H A E F F E R , B., & W A L L A C E , R. The comparison of

word meanings. Journal of Experimental Psy-chology, 1970 , 86, 144-152.

SCHIFFRIN, R. M ., & A T K I N S O N , R. C. Storage an dretrieval processes in long-term memory. Psy-chological Review, 1969, 7 6, 179-193.

SWANSON, J. M ., & WICKENS, D. D. Preprocessingon the basis of frequency of occurrence. QuarterlyJournal of Experimental Psychology, 1970 , 22 ,378-383.

STERNBERG, S. Memory scanning: Mental processesrevealed by reaction-time experiments. American

Scientist, 1969, 57 , 421-457.W A R R E N , R. E. Stimulus encoding and memory.

Unpublished doctoral dissertation, University ofOregon, 1970.

WINER, B. J. Statistical principles in experimentaldesign. New Y o r k : M cGraw-H il l , 19 62.

(Received February 6, 1971)

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