Journal oj Experimental Psychology1972, Vol. 93, No. 1, 156-162

EFFECT OF REPETITION OF STANDARD AND COMPARISONTONES ON RECOGNITION MEMORY FOR PITCH '

DIANA DEUTSCH "

Center for Human Information Processing, University of California, San Diego

In all conditions, pitch recognition was required after a 4-sec. interval duringwhich four other tones were played. The effects of including in the interpolatedsequence a tone at the same pitch as the standard (S) or comparison (C) tonewere investigated. When the S and C tones were identical in pitch, insert-ing in the interpolated sequence a tone at that pitch caused a reduction inerrors. When the S and C tones differed in pitch, inserting a tone at the pitchof the S tone produced a reduction in errors and inserting a tone at the pitch ofthe C tone produced an increase in errors. Inserting one tone at the pitch of theS tone and another at the pitch of the C tone produced no significant change inerrors, compared with the condition in which no tone at either pitch wasincluded in the interpolated sequence.

Several studies have been made ofrecognition memory for pitch when thetones to be compared are separated by aretention interval. Koester (1945) hasdemonstrated that memory for both loud-ness and pitch deteriorates with time, usingthe differential threshold (DL) as a mea-sure of memory. Bachem (1954) found acontinuing deterioration of pitch recogni-tion up to a week, yet showing that we canmaintain some sort of memory for an audi-tory stimulus over very long periods.Harris (1953) measured the DL withvarious interstimulus intervals (ISIs) undertwo conditions. When the standard tonewas fixed at 1,000 cps, the DL was foundto remain constant at around 4 cps forISIs of up to 3.5 sec., with a decline of only.8 cps with an IS I of 15 sec. With aroving standard tone varying in frequencyfrom 950 to 1050 cps, no increase in the

1 The work reported in this paper was performedin partial fulfillment of the requirement for a PhDthesis at the Department of Psychology, Universityof California at San Diego. I thank my advisor,G. Mandler, and the members of my thesis com-mittee, A. Garsia, D. M. Green, I. Jacobs, and D. E.Rumelhart, for their advice and encouragement. Ialso thank D. A. Norman for use of computerfacilities supported by United States Public HealthService Training Grant NS-07454-06. The workwas supported in part by United States PublicHealth Service Training Grant MH-1083S andGrant MH-15828-01.

2 Requests for reprints should be sent to DianaDeutsch, Department of Psychology, P.O. Box 109,University of California, San Diego, La Jolla,California 92037,

DL occurred up to a 1.0-sec. ISI. Then alinear increase in the DL was found up to15-sec. ISI where the DL was increasedby 3.7 cps. It can be concluded thatmemory for pitch decays spontaneouslywith time. However, the amount of deteri-oration manifest in 15 sec. is small.

Until recently, the effects of interpolatedstimuli on pitch recognition have not beeninvestigated. Wickelgren (1966, 1969)has found that a tone incorporated be-tween the standard (S) and comparison(C) tones produces memory deteriorationwhich increases with increased duration ofthe intervening tone. In an experimentdesigned to study the effects of increasedinterference in a retention interval of con-stant duration, the present author pre-sented 5s with a set of S and C tones,each separated by a 4|-sec. retention in-terval. A sequence of tones was inter-polated during this retention interval,always beginning at 300 msec, after theend of the S tone and ending 2 sec. beforethe start of the C tone. The interpolatedtonal sequence consisted of either four, six,or eight tones spaced regularly within theremaining time span. A statistically signifi-cant increment in errors was obtained, bothwhen the number of tones interpolated dur-ing the retention interval was increasedfrom four to six and also when it was in-creased from six to eight. It can be con-cluded that memory for tonal pitch is sub-ject to interference by other tones even

156

EFFECT OF PROBE TONES ON PITCH RECOGNITION 157

when the retention interval is held con-stant. Massaro (1970) has also reportedthat increasing the number of tones inter-polated during an interval of constantduration increases the number of errors inpitch recognition. In this experiment,Massaro varied the number of interpolatedtones between one and four.

The above findings show clearly thatmemory for pitch does not simply deterio-rate with time but is subject to some inter-ference effect. A further experiment(Deutsch, 1970b) has shown that thisinterference cannot be explained in suchgeneral terms as a distraction of attentionor a limitation in information storagecapacity. In this study it was shown thatthe incorporation during the retention in-terval of spoken numbers, which 5s arerequired later to recall, produces only aminimal decrement in the same pitch-recognition task as is severely disrupted bythe interpolation of other tones. Inter-active effects must therefore take placewithin the pitch memory store itself.The following experiment represents afurther investigation into the pitch memorystore. It was theorized that there must bea representation in memory both of theitem to be remembered, and also of thetime or order in which this item occurred.One can obtain information about theserepresentations by repeating the same itemat a different point in time, since hereitem and order information are not simul-taneously covaried. This procedure wasused in the experiment described here, Apreliminary investigation of this nature isreported in Deutsch (1970a).

METHOD

Procedure,In all experimental conditions, 5slistened to an S tone which was followed by a se-quence of four interpolated tones, and later, after apause, by a C tone. The 5s were instructed to try toremember the S tone, ignore the four interpolatedtones if they wished, and then to judge whether theC tone was or was not the same in pitch as the Stone. They then indicated their judgments bywriting "same" or "different" on paper. All thetones were of equal loudness, and 200 msec, in dura-tion. The interval between the S tone and the firstinterpolated tone was 300 msec, and the interpolatedtones were also spaced 300 msec, apart. A 2-sec.

pause was incorporated between the last interpolatedtone and the C tone.

Conditions.The different conditions of the ex-periment are shown in Fig. 1. It can be seen thatthe presence or absence in the interpolated sequenceof a tone at the pitch of the S tone was systematicallyvaried; as was the presence or absence of a tone atthe pitch of the C tone. Further, the placement ofthese critical tones in the interpolated sequencewas systematically varied between the second andthird serial positions. The entire tape consisted of96 sequences. These were presented in 12 groups ofeight. Sequences within each group of eight wereseparated by 10-sec. pauses; and there were 2-min.pauses between the groups. The sequences werearranged in random order with no separation bycondition except that each group of eight containedfour sequences in which the S and C tones werethe same in pitch, and four in which they weredifferent, to minimize the development of responsebiases. Also, no group of sequences contained morethan one example of each S and C tone pitch (seebelow) so that pitch repetition effects for thesecritical tones were minimized. The 5s listened to theentire tape on two different occasions and the resultswere averaged.

5 and C tones.S and C tone pitches were takenfrom an equal-tempered scale (international pitch:A = 435) ranging from the C# a semitone abovemiddle C to the C an octave above. The frequenciesemployed were: C# = 274, D=290, D# = 308,E = 326, F = 345, F# = 366, G = 388, G# = 411,A = 435, A# = 461, B = 488, C = 517. Each ofthese tonal pitches was employed equally oftenwithin each condition, either as an S tone, or as a Ctone, or both. When the S and C tones differed inpitch, in half of the sequences the S tone was higherthan the C tone and in the other half it was lower.

Interpolated tones.The interpolated tonal pitcheswere also taken from the equal-tempered scale(A = 435) and ranged from middle C to the C$an octave above. The frequencies employed were:C = 259, C# = 274, D = 290, D# = 308, E = 326,F = 345, FS = 366, G = 388, G# = 411, A = 435,A# = 461, B = 488, C = 517, C# = 561. Thetones in the intervening sequences were chosen ran-domly from this set, except that no sequence con-tained repeated tones unless specified by the experi-mental condition. This restriction also coveredrepetition of tones separated by exactly an octave.

Subjects.Fifteen 5s participated in this experi-ment. These were 14 University of California atSan Diego undergraduates and 1 housewife andthey were paid for their participation. The 5s wereselected on the basis of obtaining a score of at least75% correct on a small tape containing similarsequences. About one out of five applicants wasaccepted by this procedure,

Apparatus.The tones were generated by aWavetek oscillator controlled by a PDP-9 computer.The output was recorded on high-fidelity tape. Thetape was played to 5s on a high-quality tape re-corder through loudspeakers with the loudness at acomfortable listening level.

158 DIANA DEUTSCH

CONDITIONS

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

TONESTEST INTERVENING

1 2 3 4a n n n nni n m n nm n n HI nm n n n nra n m n nin n n nn nCT n ra n nra n n iii nn n iii m nra n m iii ni i i i

PROBE

M

13

lil

lil

lil

lil

lil

lil

i i

ERRORS

18.5%

2.5%

3.3%

9.2%

1.7%

2.2%

35.6%

30.0%

15.6%

10.6%

NUMBER OFJUDGEMENTS

720

360

360

360

180

180

180

180

180

180

0 1 2 3 4 5TIME IN SECONDS

FIG. 1. The different conditions of the experiment with number of judgments and percentageof errors made in each. (Each condition is diagramed by a set of rectangular elevations, each ofwhich indicates the presentation of a tone. The scale at the base of the figure indicates the timeduring which each tonal sequence is played. The initial elevation in each sequence indicates thatthe S tone occurred. The next four elevations labeled 1, 2, 3, and 4 indicate that the interpolatedtones occurred, and show their serial position. The final elevation indicates that the C toneoccurred. The initial elevations in all the sequences are labeled A and indicate the S tone. Whenthe symbol A occurs elsewhere in a sequence, this indicates that a tone at the same pitch as the Stone occurred at that time. Those final elevations which are not labeled A are labeled B. Thisindicates that the C tone differed in pitch from the S tone. An elevation in the interveningsequence labeled B indicates that a tone at the pitch of the C tone (when this differed from theS tone) occurred in the indicated position of the intervening sequence.)

RESULTS

The results of this experiment are shownin Fig. 1.

Effects of the Interpolated Tones

The effect of inserting a tone at the pitchof the S tone, when the S and C tones areidentical in pitch is shown by comparisonsof Cond, 1 with Cond. 2 and 3. A consider-able reduction in errors is produced. Forboth comparisons, this improvement issignificant on sign tests beyond the .001level.

The effect of inserting a tone at thepitch of the S tone when the S and C tonesdiffer in pitch is shown by comparisons of

Cond. 4 with Cond. 5 and 6. An improve-ment in detection of a difference betweenthe S and C tones is produced. This effectis significant for both comparisons onWilcoxon tests beyond the .01 level (two-tailed).

The effect of inserting a tone at thepitch of the C tone, when the S and Ctones differ in pitch is shown by compari-sons of Cond. 4 with Cond. 7 and 8. Itcan be seen that a striking increase inerrors occur. For both comparisons, thiseffect is significant on sign tests beyondthe .001 level.

The effect of inserting two tones, one atthe pitch of the S tone and the other at thepitch of the C tone when the S and C tones

EFFECT OF PROBE TONES ON PITCH RECOGNITION 159

differ in pitch, is shown by comparison ofCond. 4 with Cond. 9 and 10. Here thereare no significant differences in the num-ber of errors, on Wilcoxon tests (p > .05,two-tailed). Thus, the dramatic increasein errors produced when the C-tone pitchalone is included in the intervening se-quence does not persist when the S-tonepitch is also included in the same sequence.In fact, the reduction in errors producedboth when Cond. 9 is compared with Cond.7, and also when Cond. 10 is comparedwith Cond. 8 is significant on Wilcoxontests beyond the .01 level (two-tailed).Thus the benefit to discrimination producedby inserting the S-tone pitch in the inter-vening sequence effectively counteractsthe damage produced by inserting the C-tone pitch in the same sequence.

Serial Position Effects

Including in the intervening sequence atone at the pitch of the S tone produceda greater reduction in errors when thecritical tone was in the second serial posi-tion than in the third. This was true bothwhen the S and C tones were identical(Cond. 2 compared with Cond. 3) and alsowhen the S and C tones differed in pitch(Cond. 5 compared with Cond. 6).

Including in the intervening sequence atone at the pitch of the C tone, when theS and C tones differed in pitch, produceda greater increase in errors when the criticaltone was included in the second serialposition than in the third (Cond. 7 com-pared with Cond. 8).

When tones at both the pitches of the Stone and the C tone were included in thesame intervening sequence, errors weregreater when a tone at the pitch of the Ctcne was included in the second serialposition and a tone at the pitch of the Stone in the third, than when the serialpositions of these critical tones were re-versed (Cond. 9 compared with Cond. 10).This difference is significant on a Wilcoxontest at the .05 level (two-tailed).

Although only one of these effects reachedstatistical significance, all the trends de-scribed are consistent with the followinggeneralization : When the included tone was

closer in serial position to the S tone, therewas an increased tendency to identify itspitch as that of the S tone.

Effect: of Lower Compared with Higher S- andC-Tone Pitches

With the S- and C-tone pitches in thelower half of the range employed in thisstudy (274-366 cps), errors were greaterthan with the S- and C-tone pitches in theupper half of the range (388-517 cps).Errors in these two conditions were at15.5% and 9.7%, respectively. This effectis significant on a Wilcoxon test beyond the.01 level (two-tailed). It may be explainedby considering that the equal-temperedscale is a ratio scale, and so absolute differ-ences in terms of cps increase as the scaleis ascended; yet the DL for pitch over therange employed here remains roughlyconstant in absolute terms as the scale isascended (Shower & Biddulph, 1931).Discrimination would therefore be easierat the higher frequencies since here theabsolute-pitch differences between S andC tones are greater. In this experiment,however, all S- and C-tone pitches occurredequally often in all conditions.

DISCUSSION

An attempt at rigorous theoretical quantifi-cation in explaining these results appears pre-mature ; however, a theory can be suggestedwhich seems to be most in accord with thefindings.

It is proposed that memory for the pitchof a tone is laid down simultaneously both ona pitch continuum and also on a temporal con-tinuum. This may be represented as in thethree-dimensional diagram in Fig. 2. A toneis here represented as laid down in memory inthe form of a three-dimensional bell-shapeddistribution. As time proceeds, this distribu-tion spreads in both directions, but particularlyalong the temporal continuum. Also with thepassage of time, each distribution shrinks inheight, and so the more recent the tone thelarger the distribution representing it. Whenthe distributions underlying two tones overlap,the overlapping portions sum. In this way,summation between distributions underlyingtones presented at different points in time willoccur, due to the spread of these distributionsalong the temporal continuum.

160 DIANA DEUTSCH

FIG. 2. Proposed distribution underlying memoryfor the pitch of a tone.

It is further proposed that the decision as towhether a given tone presented at one pointin time (in this experiment, the C tone) is oris not the same in pitch as another tone pre-sented at a different point in time (in thisexperiment, the S tone) is made in the followingway. Assume that 5 divides the pitch con-tinuum arbitrarily into sections according tohis knowledge of the quantal steps employedin the experiment. He similarly divides thetemporal continuum into sections. He is alsoable to estimate the volume of distributionwithin each three-dimensional section (see Fig.2). Now when the C tone sounds, S examinesthe distribution in the section which corre-sponds to the same pitch as that of the C tone,and to the same temporal region as that of theS tone. He then compares the volume of dis-tribution in this section with those in sectionswhich are adjacent along the pitch continuum,but in the identical temporal region. If thevolume of distribution in this section is muchlarger than those in neighboring sections in thesame temporal region, 5 concludes that the Sand C tones were the same in pitch. Con-versely, if the volume of distribution in thissection is much smaller than in a neighboringsection in the same temporal region, 5 con-cludes that the S and C tones were differentin pitch. As the volume of distribution in theappropriate section becomes more similar tothat in a neighboring section in the same tem-poral region, the decision as to whether theS or C tones were the same or different inpitch becomes increasingly more difficult a'ndso errors more numerous. Thus, the degree ofaccuracy of discrimination is determined bythe size of a ratio between two distributionvolumes.

The diagrams in Fig. 3 represent cross sec-tions of the model on Fig. 2 taken at the pointalong the temporal continuum representing thepresentation of the S tone. The two adjacent

sections are arbitrarily labeled A and B toconform to the terminology in Fig. 1 and repre-sent a semitone difference in pitch. The S toneis always A and the C tone is either A or B.

In Fig. 3, a, no tone either at pitch A or atpitch B occurs in the intervening sequence.The distribution at this point in time is there-fore almost entirely due to presentation of theS tone A. (There will be some spread due topresentation of other tones at least a wholetone removed from A but for the purpose ofsimplicity this is not considered at present:In this experiment, such tones are randomlypresented.) There is therefore a substantialdifference in the amount of distribution in theA section compared with the B section; how-ever, errors will still be made due to thedistribution in the B section.

In Fig. 3, b, a tone at the pitch of the S tone(A) is included in the intervening sequence.The distribution underlying this included tonewill spread along the temporal continuum andsum with that already existing due to presenta-tion of the S tone A. The result shown in Fig.3, b, will be an increased volume of distributionmost specifically in the A section of the pitchcontinuum. The proportional difference be-tween the volume of distribution in the Asection and neighboring sections will thereforebe increased; and discrimination will becomemore accurate. This would explain the de-crease in errors produced by inclusion of theS-tone pitch in the intervening sequence, bothwhen the S and C tones are identical in pitch(Cond. 2 and 3 compared with Cond. 1) andalso when the S and C tones are different inpitch (Cond. S and 6 compared with Cond. 4).Further, the closer in time this included toneis to the S tone, the more will its distributionoverlap with that of the S tone and the greaterwill be the resultant improvement in discrimi-nation. This would explain the greater im-provement in performance found when theincluded tone A is presented in the second serialposition of the intervening sequence (Cond. 2and S) compared with the third serial position(Cond. 3 and 6).

In Fig. 3, c, a tone at the pitch of the C toneB is included in the intervening sequence.The distribution representing this includedtone will spread along the temporal continuumand sum with that already existing due topresentation of the S tone A. The distributionexisting at the point along the temporal con-tinuum representing the presentation of theS tone A will therefore look somewhat as inFig. 3, c. It is can be seen here that the pro-portional difference between the volume of

EFFECT OK PROBE TONES ON PITCH RECOGNITION 161

(a)

(b) B (d)

FIG. 3. Cross sections of the distributions underlying memory for thepitch of a tone under different experimental conditions.

distribution in Sections A and B is now de-creased ; so discrimination would become moredifficult and errors more numerous. Thiswould explain the increase in errors in Cond.7 and 8 compared with Cond. 4. Further, thecloser in time the included tone B is to the Stone A, the more will its distribution overlapwith that of the S tone, and so the greater willbe the decrement in performance. This wouldexplain the greater increase in errors foundwhen the included tone B is presented in thesecond serial position of the interveningsequence (Cond. 7) compared with the thirdserial position (Cond. 8). One should alsoexpect from this theory that accuracy of per-formance in Cond. 1 (S and C tones identicalin pitch, with this pitch not included in theintervening sequence) should depend verymuch on whether or not a tone a semitoneremoved from the S tone is included in theintervening sequence. Such an inclusionshould produce a substantial increase in errors.Although there is no condition in this experi-ment which formally tests this prediction, itwas found that in 8 of the sequences in Cond. 1,there was no such inclusion; and in 16 of thesequences, a tone a semitone removed fromthe S tone did indeed occur in the interveningsequence. Analysis of errors on this basisshowed that where there was no such inclusion,errors were only 12.1% and where there wassuch an inclusion errors increased to 21.7%.Such a finding would be expected on the presenttheory.

In Fig. 3, d, tones both at the pitch of the Stone and also at the pitch of the C tone areincluded in the intervening sequence. This

causes both the effects shown in 3, b, and 3, c,to occur. Thus, the volumes of distributionin both Sections A and B are increased; andso a considerable difference between them isretained. Discrimination should therefore berelatively easy. This would account for thenullification of the damage to discriminationproduced by inclusion of a tone at the pitch ofthe C tone in the intervening sequence (Cond.7 and 8) by the inclusion also of a tone at thepitch of the S tone (Cond. 9 and 10). Further,a powerful serial position effect should beexpected in this condition, since here the serialpositions of the included tones at both PitchA and at Pitch B are simultaneously reversed.And a statistically significant serial positioneffect is indeed found when Cond. 9 and 10are compared. One should also expect fromthis theory that accuracy of performance inthose sequences in which the S and C toneswere the same in pitch, with a tone at thatpitch included in the intervening sequence(Cond. 2 and 3), should depend on whetheror not a tone a semitone removed from the S-tone pitch is also included in the interveningsequence. Although there is no conditionwhich formally tests this prediction it wasfound that in 15 out of the 24 sequences inCond. 2 and 3 there was no such inclusion andin 9 of the sequences such an inclusion didoccur. Analysis of errors on this basis showedthat where there was no such inclusion, errorswere 2.4%, and where such a tone was in-cluded, errors rose to 3.7%. This increment inerrors was in the direction predicted by thetheory.

It is apparent from this study, as well as

162 DIANA DEUTSCH

from that described in Deutsch (1970b), thattonal pitch deteriorates rapidly in the presenceof other tones. This finding has importantbearing on theories of musical informationstorage. It has been suggested by severaltheorists (Cohen, 1962) that musical infor-mation (with particular reference to pitchinformation) is retained in its absolute formin an information store of limited channelcapacity. However, the rapid deteriorationof pitch information found in these experimentsdemonstrates that most of us are incapable ofshort-term storage of more than a minimalamount of absolute-pitch information, in asituation where other tones are also presented.Further, even when highly selected 5s areused, so that the average level of performanceon this task is very high, it is demonstratedin the present experiment that the presenceof a critical tone in the middle of a sequencecan have a highly deleterious effect on therecognition of the first tone in that sequence.We may recognize that a certain tone hadoccurred in a sequence without being able totell whether it was or was not the first tone inthat sequence.

It must be concluded from these findingsthat we cannot store transitional probabilitiesbetween tones with any success. It is sug-gested instead that information concerningabsolute pitch is rapidly discarded, and thatwe store pitch information in an abstracted orreceded form. This conclusion is quite con-sistent with everyday knowledge of musicalinformation processing. We recognize atune much more readily than we recognizewhat key it was played in. The same argu-ment holds for recognition of harmonic se-

quences; since not only are these transposable,but also their component chords are invert-able. A theory of how pitch information isabstracted has been described by Deutsch(1969).

REFERENCES

BACHEM, A. Time factors in relative and absolutepitch determination. Journal of the AcousticalSociety of America, 1954, 26, 751-3.

COHEN, J. E. Information theory and music. Be-havioral Science, 1962, 7, 137-163.

DEUTSCH, D. Music recognition. PsychologicalReview, 1969, 76, 300-307.

DEUTSCH, D. Dislocation of tones in a musicalsequence: A memory illusion. Nature, 1970,No. 5242, 226. (a)

DEUTSCH, D. Tones and numbers: Specificity ofinterference in short term memory. Science, 1970,168, 1604-1605. (b)

HARRIS, J. D. The decline of pitch discriminationwith time. Journal of Experimental Psychology,1952, 43, 96-99.

KOESTER, T. The time error in pitch and loudnessdiscrimination as a function of time interval andstimulus level. Archives of Psychology, New York,1945, No. 297.

MASSARO, D. W. Retroactive interference in short-term recognition memory of pitch. Journal ofExperimental Psychology, 1970, 83, 32-39.

SHOWER, E. G., & BIDDULPH, R. Differential pitchsensitivity of the ear. Journal of the AcousticalSociety of America, 1931, 3, 275-287.

WICKELGREN, W. A. Consolidation and retroactiveinterference in short-term recognition memory forpitch. Journal of Experimental Psychology, 1966,72, 250-259.

WICKELGREN, W. A. Associative strength theoryof recognition memory for pitch. Journal ofMathematical Psychology, 1969, 6, 13-61.

(Received August 23, 1971)