IrrclevantSpeechand Arliculatory Suppression
PsychologischeBeiträgc, BatvJ 44,2002, S. 166-186
Effects of irrelevant speechand articulatory suppressionon serial recall nf heard
and read materials*
HELLBRücK
MARIAKLATTE'.N,qreuNc LEr, & JüRGEN
Summarv
Immediate serial recall of verbal items is severelydisruptedwhen irrclevant background speechis presented during task performance. According to the phonological loop model, this effcct occurs because
spoken matcrial gains obligatory accessinto the phonological store, whereasvisually presenteditems must
be translatedinto a phonological code by meansof subvocal rehearsal.We testedthis assumptionby exanrining the combined effects of irrclevant speech and articulatory suppression on serial recall of digit sequencesprcscntedeither visually or auditorily. In line with the phonological loop niodel, articulatory suppression abolished the irrelevant speecheffcct when presentationwas visual. ln the auditory presentation
condition, the irrelevant speech effect rvithstood suppression (Experiments 1). Furthermorc, Experiments 2,
3 and 4 demonstratedthat, inespective ofpresentationmodality, the irrelevant speecheffect persiststhrough
a 10 second retention interval filled with articulatory suppression.These rcsults contradict the assumption
that phonological traces decay rapidly when rehearsalis prevented by articulatory suppression,but are in
line with findings on the persistenceof the phonological similarity effect. The results are discussedwith
respect to recent models of short-term memory.
Key words: short-term memory, working memory, irrelevant speech effcct, articulatory suppression,
trace decay, modality effccts
Introducti<ln
Immediateserialrecall of verbal materiaiis severelydisruptedby concurrentpresentation
of backgroundspeechwhich subjectsare instructedto ignore.This "inelevzurtspeecheffect"
(lSE) occurseven with low intensitiesof the speech,and with languagesthat the pafticipants
do not understand.With respectto the locus of the interferencecausedby inelevant speech,
thereis convincingevidencethat it affectsrehearsal,but not encodingand recall of the items
(e.g.,Miles, Jones& Madden l99l;Baddeley & Salam61986).The effect has beeninterpretedwithin the framework of the phonologicalloop model proposedby Baddeley(1986,
1990, 1992).The phonologicalloop is a sub-componentof working memory which servesas
a storagesystemspecializingin the rctention of speech-based
rrraterial.According to Baci-
161
deley'smodel, the phonologicalloop consistsof two parts. The lirst is a passive storage
componentwhich holds speech-based
information in a phonologicalcode which is independent of input modality. The secondis an active rehea.rsalprocess,basedon speech-output
mechanisms,
which servesto refreshthe contentsof the phonologicalstore in order to prcventtracedecay.Without rehearsal,phonologicaltracesareassumedto decayrapidly after I 2 seconds.Additionally, the rehearsalprocessis necessaryfor re-coding visually presentcd
itemsinto a phonologicalcodenecessaryfor entry into the store.Conversely,heard(spokon)
itemsare assumedto gain direct accessto the phonologicalstore, without the mediationof
therehearsalprocess.
This model is basedon a collectionof empiricalfindings concerningthe combincdeffects
of articulatory suppression(concurently uttering a simple syllable such as "the"), word
length(poorerperformancefor long than for short words; Baddeley,Thomson& Buchanan
1975),phonemicsimilarity (poorer performancefor similar soundingitems; Conrad 1964),
and irrelevant speech(Salam6& Baddeley 1982). When the items are presentedvisually,
blorckingthe rehearsalprocessby meansof articulatorysuppressionabolishesthe effects of
word length, phonemic similarity and irrelevant speech.This is assumedto occur becausc
arliculatorysuppressionpreventsvisually presenteditems from being phonologicallyrecoded
andregisteredwithin the phonologicalloop. With auditorypresentation,articulatorysuppressionabolishesthe word length effect,but leavesthe phonologicalsimilarity effect unaff'ected
(Baddeley,lrwis & Vallar 1984).Accordingly, theseeffects seemto reflect differcnt componentsof the system.The word length effect is assumedto reflect the reherusalprü)ess,
whichis disruptedby articulatorysuppression.The phonologicalsimilarity ef-fectreflectsthe
phonologicalstore.Sincerehearsalis not necessaryfor speechto cnter the store,its contribution to performancepersistswhen articulationis suppressed.
Accordingto Bacldeley'smodel, irrelevantbackgroundspeechgains obligatory accessto
the phonological store, where it interferes with the representationsof the rccall stimuli.
Originally,this intederencehas beenexplainedwith respectto phonemicsirnilarity. That is,
themagnitudcof the disruptionhas been assumedto dependon the similzrity betweenthe
irrelevantspeechand the items to be recalled(Salam6& Baddcley 1982).This view has been
challengedby recentfindings which consistentlyshow that the degreeof similarity between
theheud and read material doesnot affect the ISE (Buchner,Irmen & Erdfelder 1996;I nCompte& Shaibe1997;Jones& Macken 1995).Therefbre,an altemativeexplanationol'the
inelevantspeecheffect has been proposedby Jonesand colleagues(c.g., Jones,Maddcn &
Miles, 1992;Jones,1995, 1999).Theseauthorsarguethat the ISE resultsfrom differcnt scls
oforder cuesbelongingto scquercesofauditory and visual origin. According to this vierv, a
strearnof auditoryeventsis automaticallyreprcsentedin shorl-termmcmory as a sequcnccol'
objectsjoined by linkages.Theselinkagesare supposedto disrupt the associationsbetween
theitenr in the to-be-remembered
list, that is, order- but not item-informationis affcctcd by
inelevantspeech'.The magnitudeof the clisruptionby irelevant soundsdependson the
strengthof the iinkagesbetwccnthe items in the irrclevantstream,which in turn dependson
'
Dr. Maria Klatte, University of Oldenburg, Dcpt. of Psychology, [nstitute for Research on ManIlnvironment Rclations,P.O.B. 2503, D-26111 Oldenburg,e-mail: [email protected]
'
Dr. Jürgen Hellbrück, Catholic University of Eichstätt, Dept. of Psychology,Environmental and Hcalth
Psychology.While preparingthis article Jürgen Hellbrück rvas a lbllowship membcr at the llarlse Institute
for Advanccd Study in Delmenhorst.
* Part of the studv r.vassunnortedbv DF6 ffiE 1276/5-l\
'Since
the disruption occurs with both speech and tones (Jones & Macken 1993), the tenn "Inclevant
SpeechEfl'ect" might be substitutedby "lrrelcvant Sound Effect", as proposed by Beaman and Jones
(1997).However, there is also evidence indicating significant differenccs between the cffects ol speech
and toncs (Ncath, Surprenant& LeCompte 19981LeCompte, Neely & Wilson 1997; Klatte, Kilcher &
Hellbrück 199-5).
168
169
M. Klatte.N. ke. J. Hellbriick
krelevant SpeechandAfiiculatory Suppression
the clegee o{'change between adjacent iterns. Sequencesconsisting of different auditory
events(e.g. difi'erenttonesor different syllables)producernore disruptionthan lcpetitionsof
single iterns.Ttis changingstate- hypothesishas been supportedby numerousexperiments.
Ilowever, in our view, these findings are not sufficient to abandonthc phonological loop
interpretationof the ISE altogcther.Thcy clonot contradictthe core assumptionthat the interferenceoccursin a short-tcrmstorethat is specializrdfor the retentionof speech-based
materials. Severalconrputationalmodels of the phonologicalloop are curently under development, which refer in detail to the problem of serial order and migh( shorlly be able to give a
rnoreadequateaccountof the ISE than the original model (Burgess& Hitch 1999;Henson
l99tl; scealsoBaddclcy2000).
lrrespectiveof the undcrlying mechanisms,the disruptive effect of iuelevant spccchon
imrnediateserial recall of verbalitens is a stableand robustphenomenon-Thercforc,we use
the ISE as an indicatorofthe codesusedin this task.Furtherconsiderationofthe Joneset al.
model will be postponedto the generaldiscussion.
Returning to Baddeley'snrodel, two empirical predictionsmay be derived from the assumptionthat inelevant speechhas direct accessinto the phonologicalloop. First, in combination with articulatorysuppression,the ISE should behavejust like the phonologicalsimilarity effcct: lt shouldbe abolishedby articulatorysupprcssionwhen thc stimuli arc presented
visually, and it should withstand suppressionwhen presentationis auditory. Second,inespective of presentationmodality, the irrelevant spcech cffect shouid be aboiishcd when
recall is delayedby a retentioninterval filled with articulatoty suppression.This is because
articulatory supprcssionpreventsthe iterns from being refreshedby meansof subvwal rehearsal,lcading to rapid decayof the contentsof the phonologicalstore.Consequently,after
severalsecondsof interpolatedarliculatory activity, the phonologicalstore should no longer
contributeto perforrnanceand the effectsof phonemicsimilarity and inelevant speechshould
disappear.However, in a study of Longoni, Aiello & Richardson (1993), the effect of
phonologicalsimilarity on recall of spokenword lists was not reducedwhen the participants
were requiredto suppressarliculationduring presentation,a lO-secondretentioninterval and
recall of the lists. This result suggeststhat hearditernscan be retainedin short-tennmenrory
without the help ofserial rehcarsalfor at lcast 10 seconds.
With referenceto the combinedeffectsof articulatorysuppressionand irrelevantspeech,
severalstudieshave consistentlyshown that with visual prcscntation.the inelevant speech
effect is abolishedby articulatory suppression(Salam6 & Baddeley 1982, Exp. 3; Miles,
Jones& Madden 1991,Exp. 3; Hanley 1997).On the other hand, there is only one study
examining the effects of articulatory suppressionand irrelevant speechon serial recall of
auditorily presenteditems (IJanley& Broadbent1987).The resultsof this study are equivocal. In the first experiment,thc ISE was abolishedby arliculatory suppression,while in two
furtherexperiments,the ISE withstoodsuppression.
The predictedpattern of interactionsbetweenthe ISE and articulatorysuppressionwith
rcspect to presentationmodality is essentialfor the phonologicallorp interpretationof the
ISE, as well as for thc assumptionofdifferential accessto the phonologicalstorefor readand
heardn"nterials.Therefore,the Hanley & Broadbentstudy clearly merits replication.Experiment I of this study was conductedto test for this pattern of interactionsby analyzingthe
combinedeffects of irrelevant speechand articulatorysuppressionon serial recall of itenm
presentedeither visually or auditorily. Experiments2 to 4 aimed to analyze the temporal
persistenceof the phonologicalfface by studying the effects of an interpolateddclay fillecl
with articulatorysuppressionon the magnitudeof the irrelevzurtspccchefTect.Following the
Baddeleymodel, the ISE shouldbe abolishedwhen articulationis suppressedin the prescntationand in a long-cnduringretentionphase,irrespectiveof the presentationnrodality.However,accordingto the resultofLongoni's et al. (1993)study,we expectan ISE aftera retention interval which is remarkablylonger than the duration of the phonologicaltrace postulatedby Baddeley.
Experiment 1
In this experiment,we examinedthe combinedeffects of articulatorysuppressionand irrelevantspeechon immediateserialrecall of sequences
of digits which wcre presentedeither
visually or auditorily. According to the phonologicalloop model, articr-rlabrysuppression
shouldabolish the ISE when the items are presentcdvisually, but not whcn presentationis
auditory.
Method
Participants
Forty-eightstudentsfi'om the University of Oldenburg, 14 male and 34 female, participatedin the experiment.Their medianage was 26 ycars,with a rangc between20 and 35. All
hadnormal or correctedvision and normal hearing.They were either paid for their panicipation or reoeivedcoursecredit. The participantswere assignedat random to one of two experimcntalgroups,one for auditory,the other for visual presentation.
Taskand Materials
Serial recall /ask: In eachtrial, the digits I to 8 werp prescntedin randomorder without
repetition. Presentationwas followed by immediate serial recall. For both prcsentation
modes,the presentationof eachsequencewas precededby a visual waming signal in fonn of
a red squarewhich was shownin the centreof the computerscreenfor 1ü)0 rns, followed by
a 500 ms pause.The presentationrate was I digit per second,with an interstinrulusinterval
of 200 rns. Immediately after presentationof the last digit, 8 squareswerc shown on the
computerscreen,with the digits 1 to 8 randomlyassignedto the squares.The participantshad
to recall the presentedsequenceby clickiug the digit squareswith the ntousein the order of
presentat.ion.
Clicking of the eighthresponseautomaticallyinitiated the beginningof the next
trial. The participantshad no opporlunity to correct mistakesor to leave blanks. This recall
prrcedurehasproved successfulin a seriesof prior experiments(Klatte, Kilcher & Hellbrück
1995;Ellemeier & Hellbrück 1998) and is quite similar to that used recently by other'
authors(Surprenant,t-cCompte& Neath, 1999;Meiser & Klauer 1999).
t70
In the visual presentationcondition,the digits were shown one aftcr anotherin the centre
of the cornputerscreen.Fol the auditory presentationcondition, digital recordingsof the
digits 1 to 8, spokenin a female voice, were prepzuedwith 8-bit-resolutionand a sampling
rateof 22 kHz. Randompermutationsof thesesoundfiles were prcsentedmonatrally via two
loudspeakcrspluggedinto the computer.The spcakerswere placedon the left and right sides
of the computerscreenin front of the participant.
Irrelevant speech:A digital audio tape with Russian speechspoken by a male voice
leading a newspaperarticle was used as irrelevant backgroundspeech.Insteadof silence,
pink noise was usedas a control condition. Unlike speech,broadbandnoisedoesnot disrupt
seriairecall performance(e.g.Salam6& Baddeley1983,1987, 1989,Jones,Miles & Page
1990; Klatte, Kilcher & Hellbrück 1995).The backgroundsoundswere presentedvia two
loudspeakerslocalized laterally behind the participants,with a comfortablesound level of
approximately60 dB(A). Pilot studiesrevealedperfect intelligibility of the spokendigits in
both backgroundsound conditions. The backgroundsoundswere presentedcontinuously
throughoutthe appropriateexperimentalbl<rck.
Articulcrtorysuppression:Articulatory suppressionis an often usedprocedureto prevent
rehearsal.ln the arliculatorysuppressioncondition,the piuticipantswere requiredto utterthe
syllablc "be" continuouslyat a rate of about 3 times per 2 secondsduring the presentation
phase.No suppressionwas requiredduring recall becausein pilot studies,someparticipants
repoiledditficulties in conrbiningthe responseclicking with the articulatorytask.u
Resultsand Discussion
were scoredin tenns of a strict serial positioncriterion: Each item not recalled
Responses
in the correct position was scoredas an error. The resulting serial position curvcs for the 4
conditionswith and without irrelevant backgroundspeechand articulatory suppressioltare
shownin figure lA (visual presentation),and 18 (auditory presentation).Overall meal)sarc
eivenin Table l.
A)
uor B)
80l
ot)
'o ro)
70+
Eeo
rso
r
o4o
r30
20
10
0
60
-.-ls/AS
+PN/AS
50
40
-^-IS/Control
30
_*-
20
10
fact that the subjectswere fiee to rehearseduring recall is not impodant herc, sincc it does not affect
thc hypothcsisthat thc conrbinedeffects of suppressionduring presentationand IS diffcr with presentation
nrodality.
4
5
7
6
Serial Position
Design and Pntcedure
'Thc
PN /
Control
0
3
The designwas a 2 x2x2 x 8 mixed factorialdesignwith presentation
modality(visual
vs. auditory) manipulatedbetweensubjectsand irrelevant speech(Russianspeechvs. pink
noise),articulatorysuppression(continuouslyutteringthe syllable "be" vs. remainingsilent)
and serialposition (l to 8) manipulatedwithin subjects.
Participantswere tcsted individually in a sound attenuatedlaboratory.Writtcn instructions describedthe serial recall task and stressedthe requirementto utter the syllable "be"
continously and smoothly during the supprcssionconditions. Prior to the experiment,the
parlicipantsperfrrmeda practicesessionconsistingof9 trialsunderarliculatorysuppression.
In tlre proper expedment,eachparticipantpedormed4 blocks of 24 sequenceseither under
pink noise or Russianspeech,with or without articulatorysuppression.The order of conditions was counterbalanced
betweenpar-ticipants.The experimenttook about 65 minutesto
complete.In all experimentsreporlcd in this study, the participants'perfonxancewas carelully nronitoredby the experimentcr,who stayedin the room during the entire sessions.Especially, with respectto the suppressionconditions,the experimenterensuredthat all subjects
articulatedin a comparableand constantvolume.and that they did not stop or intemrpt their
arliculation.
lll
IrrelevantSpeechand Articulatory Supprcssion
M. Klatte, N. tee, J. I{ellbrück
Fig. 1:
Serialpositioncuryesrepresentingthe effectsofirrelevant speechand
articulatorysuppressionin Exp. l. A) Visual presentationB) Auditoty preselltation
(IS: inelevant specch,PN: pink noiseAS: articuiatorysuppression)
Table l:
Mean percentageerrorspooledover serialpositionin Exp. I
VisualPresentation
Auditory Presentation
28.r9
28.78
Speech/ Control
36.9
3 7 . 81
Noise/ Suppression
49.32
40.5
Speech
/ Suppression
49.0
46.98
Noise/ Control
112
lnelevant Speechand Atliculatory Suppression
M. Klatte,N. Lre. J. Hellbrück
The overall analysisyielded no significantdifferencebetweenthe visual and the auditory
group (F(1,46)<1).The interactionbetweenpresentationmodality anclbackgroundsounddid
nol.reach signi{icance(F(1.46)=0.68).However, there was a signihcant interactionbetwcen
articulatorysuppressionandpresentationmodality (F( 1,46)=4.18;p<0.05),indicating a larger
effect of suppressionin the visual presentationgroup. The interactionbetweenmodality and
p<0.01).As canbc seenin Fig. 1, this
serialpositionwashighly significant(F(7,322)=18,76,
intcractionreflectsthe standard"modalityeffect" (seee.g. Penney1989),that is, betterperformancein the recencyportionof thc list with auditorypresentation.
In the visual group, performanceis worse under Russianspeechthan under pink noise
when zuliculationis not suppressed.With suppression,this differenceis completely elirninated.The slatistical analysisof thesedata conllrmed significarrtmain effects of irrelevant
(F(1,23)=56.96;
p<0.01),and scrial
speech(F(1,23):1.99 p<0.01),articulatorysuppression
position (F(7, 1611=66.76'p<0.01). and a significant afticulation-by-serialpositioninteraction(F(7,161)=3.45;p<0.01). Morc impotlanl the significantinteractionbetwecn
irrelevantspcechand articuiatorysuppression(F(1.23)=7.l tt; p<0.05)revealeda largerefl'ect
of irrelevant speechwhcn articulation was not suppressed.Pairwise comparisonsof means
rusingthe Student-Newman-Keuls
test shou,edsignificantdifferencesbetu'eenpink noiseand
speechwhen articulation was not supprcssed(p<0.01). When combined with arliculatory
suppression,therewas no differencebetweenthe noisc and speechconditions.
For auditory prcsentation.Fig. lB shows worse perfomranceunder Russianspeechthan
underpink noise in the control as well as in the suppressioncondition.This impressionwas
confirmcdin the statisticalanalysis.The ANOVA yieldedsignilicantrnaineffcctsof inelevant speech(F(1,23)=22.89;
p<0.01),articulatorysuppression
(F(1,23)=31.15;
p<0.01),and
serialposition(F(7, 161)=166.1;p<0.01),aud significantinteractionsbetweensupprcssion
iurdserialposition(F( 7,161)=4.26;p<0.01)as well as betweenirrelevantspecchand serial
position (F(7,161)=14.46;
p<0.01). The interactionbetweensuppressionand background
speechdid not approachsignificance(F(1,23)<1),indicatingindependenteffectsof irreievant
speechand suppression.Pairwise comparisonsproved better pcrformanceunder pink noise
than under Russianspeech,both with and without articulatory suppression(p<0.01 in both
cases).
Tlrc resultsof ExperirnentI arc clear-cut.Arlicu.latorysuppressionand irrelevantspeech
interactdifferently with respectto presentationmodality. For visual presentatioll,the irelevant specchefl'ect is completely abolishedwhen arliculation is suppresscdduring presentation. For auditorypresentation,the irrclevantspeccheffect withstandssuppression.
A simiiar pattern of interactionshas been shown for thc phonologicalsimilarity elfect
(Baddelcyet al. 1984;Longoniet al. 1993,Exp. l). Consequently,
this resultis clcarlyin line
with the assumptionthat speecl.r
gains obligatory and direct accessto the phonologicalstore,
wheLeasvisuallyprescntedverbalmaterialhas to be translatedinto a phonologicalcodeby
meansof subvocalrehearsal.This translationis preventedby articulatorysuppression.
In conclrrsion,the resultsofExperiment I confirm Baddeley'shypothesisof different acccssto the phonologicalstorefor heardand readmater-ials.Additionally, they agrcc with the
prcdictionthat visual materialmust be articulatedin order to becomesusccptibleto iffelevant
spcech.In the following experiments,we usedthe inelcvant speccheflect as a meansto
invcstigatethe temporalpersistcnceof the tracesgeneratcdin l.heserialrecall task.
173
Experiment 2
According to the phonologicalloop model, phonologrcaltracesare subjectto rapid decay
after l-2 secondsunlessthey are refreshedby continuoussubvocalrehearsal.this assumption is basedrnainly on the word length effect (Baddeley,Thomson& Buchanan1975),that
is, evidencethat scrial recall performancedependson the articulatory durationof tl'rcitems:
Parricipantscan recall a complete sequencewhen thcy are able to arliculate it in approximately 1.5seconds.In order to maintainthe iternsover a period of about2 seconds,lhc processof subvocalrehearsalhas to be available.sAlthough the time-courseof the temporaldecay is not lully specifredwithin thc phonologicalloop rnodel,we assumethat after a l0 secondsrctentioninterval filled with arliculatory suppression,the phonologicaltracesshould be
entirely lost, and the effects of phonologicalsimilarity and irrelevant speechshould disappear.This shouldsustainfor readas well as for heardstintuli.
ln this experirnent,we comparedthe combinedeffects of irrelevantspeechand articulatory suppressionon serial recall of visuatly and auditorily prescnteddigits when rccall was
delayedby a 10 secondsretentioninterval. Following the phonologicalloop model, the ISE
shouldbe abolishcdwhen articulationis suppresscdduring presentationand retentionintcr'val, inespectiveof presentationmodality. However, accordingto the findings on the persistenceof the phonologicalsimilarity effect reportedby Longoni et a1.(1993), the ISE should
withstandthe suppression-filledinterval when the digits areptesentedauditorily.
Method
Participants
Fofly-eight studentsfrom the Univcrsity of Oldenburg,aged between 19 and 35 yeals
(median:24years), served as participants.17 were male and 3l were fcmalc. They were
eitherpaid for their participationor receivedcoursecrcdit. None of them had talten peul iu
experiment1. The participantswere randomly assignedto one of two expedmcntalgroups
(visualvs. auditorypresentation).
Taskand Materials
Thc irrelevantbackgroundsoundswere the sarneas in Experiment l. The sorial recall
taskwas identical to that used in Experiment l, with the exceptionthat in each trial, a 10
secondretentioninterval was introducedbetweenthe prescntationof the last digit and the
beginningof the recail phase.The computerscreenremainedblank dur'ingthe retcntion interval.The presentationofthe 8 squaresfilled with the digits servedas a cue to startrccall.
'Although
a growing number of studiesquestionsthis explanationof the word length effect (e.g., tsrown &
Hulme 1995; Neath & Naime 1995; Service 1998), other evidenceconfirms thc dominant rolc of rchearsal
in imme<liatememorv span (Cowan et al. 1998).
114
M. Klatte. N. tre. J. Hellbrück
IrrelevantSpecchand Articulatory Supprcssion
In the articulatory suppressioncondition, the participantshad to articulate the syllable
"be" continuouslyduring presentationand retentioninterval. As in the previousexperimeut,
the backgroundsoundswere presentedcontinuouslytlroughout the appropriateexperimental
blcrcks.
Table 2:
Mean Percentage
Errorspooledover Scrial Positionsin Exp. 2
Design and Procedure
Procedureand designwere identical to Experinrent1. Becauseof the retentioninterval,
the presentexperimenttook somewhatlongerto complete(approximately75 minutes).
Results and discussion
Figure 2 illustratesthe meanerror ratesfor the four experimentalconditionswith respect
to serial position for visual (Fig 2A) and auditory (Fig. 28) presentation.Overall meansare
eiven in Table 2.
TO
60
%
E
r
-.-IS/^S
50
40
.
r 30
ozo
r
-r
PN /AS
-IS / Control
10
+PN
/ Control
0
12345678
Serial Position
12345678
Serial Position
Fig.2:
EfTectsofirrelevant speechand articulatorysuppressionon delayedserialrecall (Exp. 2).
A) Visual presentationB) Auditory presentation
(IS: imelevantspeech,PN: pink noise,AS: articulatorysuppression)
175
Visual Presentation
Auditory Presentation
Noise/ Control
17.1
26.45
Speech/ Control
25.2
33.29
Noise/ Suppression
37.88
39.48
Speech/ Suppression
36.67
44.72
A combinedanalysisyielded a signihcant main effect of presentationmodality, indicating better pcrformancewith visual than with auditory presentation(F(1,46)=5.76;p<0.05).
The effects of irrelevant speech and arliculatory suppressionwere highly significant
(F(1,46)=24.31;
p<0.01 and F(1,46)=130.M;p<0.01,respcctively),but did not differ bc(F(1,46;)=2.35:
tweenvisualand au<litorypresentation
p<0.133andF(|,46)=2.19;p<0.146t.
As in Exp. 1, the typical modality effect was reflected by a significant serial positiorr-bymodalityinteraction(F(7,322-7.89,p<0.01).Furthermore,the three-wayinteractionbetween
presentation modality, suppression and irrelevmt speech approached significautce
(F(1,46)=3,84;p<0.056), indicating modality-dependentdifferencesbetweenthe combined
effectsofirrelevant speechand suppression.For further details,sepal'ateanalysiswas carricd
out on the datafor visual and auditoryprescntation,respectively.
Again, in the visual presentationcondition, the analysisyielded a significant interaction
betweenirelevant speechand articulatory suppression(F(1,23)=10.72;p<0.01). Pairwise
comparisonsusing the StudentNewman-Keulsprocedurcindicatedbettel performanceunder
pink noisethanunderRussjanspeechwhen articulationwas not suppressed
(p<0.01).ln thc
articulatorysuppressioncondition, the backgroundsound conditions did not differ. Conversely,for auditory presentation,the interactionbetweenirreievant speechand suppression
did not approachsignificancc(F(1,23)<l). Pairwise comparisousyielded significanr dif'fer-encesbetween noise and speechin the con[ol as well as in the suppressionconditions
(p<0.0I andp<0.05,respectively).
For auditory presentation,articulatory suppressionduring presentationand a l0-second
retentioninterval did not remove the irrelevant speecheffect. This result contradicts thc
assumptionof rapid temporaldecayof the phonologicaltraceswhen rehearsalis prevented.
Civen the theoreticalimportanceof this point, we tried to rcplicatc this result in a lurther
experimentusing a more conventionalrecall procedure.Further discussionof Experiment2
will be postponeduntil we considerthe resultsof Experiment3.
116
lnelevant Speechand Articulatory Suppression
M. Klatte. N. [ec. J. Hcllbrück
Experiment 3
ln this experiment,we examinedthe effectsof inelevant speechand articulatorysuppression on scrial rccall of itcms presentedauditorily. As in Experimcnt 2, suppressionwas requircd during presentationand a l0 secondsretention interval. The onJy differencein task
structurewas that in Experiment3, the participantshad to recall the sequencesby writing
them down on preparedresponsesheets.
In the precedingexperiments,responseswere given by clicking on the digit-filled squares
in the order ofpresentation.The suggestionthat this procedureenablesthe participantsto use
visuo-spatialcoding seemsunwarrantedsince for each trial, the digits were randomly assignedto the 8 squares.As mentionedabove,this procedurehas beenused successfullyin a
serieso[ prior studieson ir:relevantspeech(Klatte, Kilcher & Hellbrück 1995;Elletmeier &
Hellbrück 1998) and has recentlybeen usedby other authors,showing clear effects of word
length (Neath,Surprenant& lrCompte 1998),phonologicalsimilarity (Surprenant,Neath &
LeCompte 1999; Nairne & Kelley 1999), and articulatory suppression(Meiser & Klauer
1999).Nevertheless,in the presentexperiment,we attemptedto replicatethe secondexperiurcnt'skey finding using the more conventionalwritten recall procedure.
Nlethod
Ill
toldto recallthefirst digit first, thenthesecondetc.,by writingthedigitsstrictlyäom leli tcr
rightin theapp:opriate
boxeson theresponse
sheet.
Results
Figure3 showstheserialpositioncuryesfor eachof the4 experimental
conditions.
-.
%
+PN
50
E
40
f
30
r
20
o
r
10
-IS / AS
-r
i AS
-IS / Control
+PN
/
Control
0
3456
Participatüs
Twenty-lbur studentsfrom the University of Oldcnburg,6 male and 18 female,servedas
participants.'fhey were aged between 19 and 35, with a median age of 23 and were either
paid for their participationor receivedcoursecredit. None of the participantshad taken part
in a previousexperiment.
Serial Position
Fig. 3:
Eff'ectsof irrelevantspecchand afticulatorysuppressionon dclayedserialrecall of auditorily
presenteditems using a written recall procedure(Exp. 3).
(lS: irrelevrmtspeech,PN: pink noise,AS: articulatorysuppression)
Ta,skand Materials
'lhe
irrelevantbackgroundsoundswere thc samcas in ExperimentsI and 2. The task was
the saureas in the auditory prescntationcondition of Experiment2, with the exceptionthat.
after the l0 secondsretcntion interval, the message"Bitte schreiben"("Pleasewrite") was
shown on the screcnas a cue to stiut recall. The participantshad 15 secondsto write down
their rcsponseon preparedresponsesheets.After this period, the next trial was automatically
itritiatedwith the presentationof the red squarewaming signal.
Desigttantl Procedure
The dcsign was a 2 (inelevant speech)x 2 (articulatorysuppression)x 8 (serial position)
factorial design with repeatedmeasul€son all factors.The procedurewas identical to the
auditory condition of Experirnent2 with l"heexceptionthat in Experiment3, written recall
was rcquircd.The instructionstressedthe irnportanceof strict serial recall: Paflicipantswere
A three-factorialrepeatedmeasurementANOVA yielded significant main cft'ccts of irrelevantspecch(F(1,23)=35.69;
p<0.01),arliculatorysuppression
(F(1,23)=140.66;
p<0.01),
andserial position (F7, 161)=88.0;p<0.01).Furthennore,there were signilicant interactions
betweenirrelevantspeechand serialposition(F(7,161)=13.64;
p<0.01),and betweensuppressionand serial position (F(7,161)=8.98;p<0.01),and a significant3-way interaction
betweenirelevant speech,suppressionand seriai position (F(7,161)-2.68;p<0.05). Figure 3
indicatest"hatthe efTectsof irreievant speechand suppressionare more pronounceclin the
secondhalf of the list.
Coinciding with our previousresults,the interactionbctweenirrclevant speechand suppressiondid not approachsignifrcance(F(1,23)<1). Mean percentageelaors pooled ovcr
serialpositions were 23.92 in the noise condition and 30.8 in the speechcondition whcn
articulationwas not suppressed.With suppression,error rates were 31.33 in the noise and
42.15in the speechcondition. Pairwisecomparisonsyieided significant differencesbetween
inelevart speechandpink noisein both suppressionconditions(p<0.01).
n8
IrrclcvantSpeechand Articulatory Suppression
M. Klatte. N. ke. J. Hellbrück
Discussion
the key finding of Experiment2 was exactly replicatedin Experiment3. Obviously, the
result does not dependon a specific recall procedure.Articulatory suppressionduring presentationand a lO-secondretentioninterval doesnot abolishthe irelevant speecheffect when
presentationmodality is auditory.The dataprovideclby Longoni et al. (1993)suggestthat tlrc
sameis true for the phonologicalsimilarity effect. Theseresultsare not in line with the assurnptionthat phonologicaltraces are subject to rapid decay unless they are ref'reshedby
meanst-rl continuousrehearsal.Rather,they suggestthat phonologicaltracesc:anbe maintaineclin short-termmemory without the help of serial rehearsalfor at least 10 seconds.The
following experimentwas aimed to test whetherthe long temporalpersistenceis specific to
the auditorymodality, as proposedin modelsstressingrnodalityeffectsin short-termmemoly
(e.g. Cowan 1984,Penney1989;Naime 1990),or if, underthe appropriateconditiotrs,traces
of visual origin turn out to havethe sametemporalduration.
179
Resultsand Discussion
The serialoositioncurvesfor eachofthc 4 conditionsare shownin fisure 4.
-G -ls /AS
60
---.-l'N
%50
40
-r
/AS
-IS / Control
E30
r
+PN
r20
o
10
/
Control
r
Experiment 4
Up to this point, our data do not allow any conclusionsconcerningthe temporalcharacteristics of phonologicai traces derived from visual origin. In the precedingexperiments,
suppressionwas always requiredduring presentationand retentionof the stimuli. Hence.irt
terms of the working memorymodel, the items cannotenter the phonologicalstoreas articulatory suppressionpreventsthe translationof written stimuli into a phonologicalcode. Consequently,in this experiment,visual presentationwas used,and articulatorysuppressionwas
confinedto the retentioninterval. During presentation,the parlicipantswere free to rehearse.
That is, they were able to translatethe graphemicstimuli into a phonologicalcode,but were
preventeclfrom ret'reshingthe items by rneansof subvocalrehearsal.Under theseconditions,
the inelevant speecheffect should withstandthe suppression-filledinterval for visually presentedmaterials.
Method
Particiltartts
28 studentsof the Universityof Oldenburg,agedbetween18 and 34 years,participatedin
this experiment.Tlrey wele either paid for their participationor receivedcoursecttdit. None
of them had takenpart in a previousexperiment.
7'askand.Procedure
1'he.experimentwas identical to the visual presentationcondition of Experiment2, with
the cxceptionthat afticulatorysuppressionwas confinedto the retentioninterval.The panicipantsbeganto articulatethe syllable "be" immediatelyafter presentationof the eighth digit.
and stoppedwhcn the 8 squarcsappearedon the screen.
0
12345678
Serial Position
Fig.4:
Effectsof irelevant speechand articulatorysuppressionon delayedserialrecall of visually
presenteditems, with suppressionconfinedto the ret"entioninterval (Exp. 4).
(IS: irrelevantspeech,PN: pink noise,AS: articulatorysuppression)
A 2x2x8 repeatedmeasurementANOVA yieided signihcant efi'ectsof irrelevantspeech
(F(1,21)-41.3;p<0.01),
(F(1,27)=37.42;p<0.01),
articuiatorysuppression
and scrialposition
(F'(7,189)=76.37;
p<0.01).There were significant interactionsbetweenirelevant speechand
seriaiposition (F(7,189)=2.95;p<0.01), and betweenarticulatorysuppressionand serial
position(F(7,189)=5.99;
p<0.01),indicatingstrongerefTectsof suppression
and igelevalt
speechin the secondhalf of the list. Contrary to the precedingexpedments,the interaction
betweenirrelevantspeechand suppressiondid not reach significance.Mean error ratesinespectiveof scriiripositionswere20.46in the noisecondition and 32.5 in the speechcondition
whenarticulationwas not suppressed.
With suppression,enor rates were 32.79 uniler noise
and38.93 under speech.Pairwisecomparisonsusing the Student-Ncwman-Keulsprrredure
provedsignificantdifferencesbetweenirrelevantspeechand pink noisc in the control as well
asin the suppressioncondition(p<0.01in both cases).
This result showsthat the disruptiveeffect of inelevant speechon serial recall of visually
presenteditems suwives a l0-secondretentioninterval filled with articulatorysuppressitln.
Similar results have been shown with respect to the phonological similarity effect by
Richardson,l,ongoni & Di Masi (1996). In this study, the phonologicalsirrularity effect on
serialrecall of word list presentedvisually persistedtfuough retention intervals up to 20
secondsfilled with articulatorysuppression.ln conclusion,the evidencefavoursthe assump-
t8r
M. Klatte. N. t-ee.J. Hellbrück
lrrelevantSpeechturdArliculatory Supprcssion
tion of a long-endulingphonologicaltracewhich can be n.nintainedup to 20 secondswithout
the help of subvocalrehearsal.
changingstateeffect is a key characteristicofthe ISE on visually prescntedlists (seeabove).
Thefact that it docsalsooccurwith heardlists indicatesthat the mechanisnrs
underlyingthe
disruptionaro the samefor both presentationmodalities.
Second,it might be arguedthat thc suppression
techniquewe uscdwas not sufficientin
completeiyundurnining the rehearsalprocess.However, the use ol'arliculatory suppression
as a meansto block rehearsalhas a long history (e.g., Murray 1968).Thus, tlri.sobjection
would hold fbr a vast amount of studies in the domain of verbal shorl-term nremoly. As
statcclabove,the performauoeof our subjectswas strictly monitured,therebyensuring that
they arliculatedin a continuousand audible way with constantintensity. 'Ihe efficiency oi
this techniqueis detnonstratedby thc fact that it obviously blocked the proccssof recoding
visuallypresentedstirnuli in ExperimentsI and 2.
Longoniet al. (1993)as well as Richardsonet al. (1996)proposethat thc temporalpersistettce
of the phonologicaltracein workingmemoryis sinrplyrnuchlongerthanpreviously
assumed.
Howevcr, this is a seriousproblem for the phonoiogicalloop model, which relics
heavilyon the interplaybetweenrapid tracedecayand subvocalrehearsal,ln the follou'ing,
thefindingsarediscussedwith respectto alternativemodelsof short-termmetnory.
In the framework of the O-OER rnodel proposedby Jones (1993, Jones, Beanran&
Mackeni996), the changing-stateaccountofthe ISE mentionedin the introductionhas been
extendedto a generaltheory of interfercncein serial shorl-tcrm memory. ln contrastto lladdeley'sdistinction betweenauditory codesin the phonologicalstore and an arliculatory r-ehearsalprrcess, the O-OER model assumesthat abstractand amodal representatlonsalc
generated
from items of visual, auditory and articuiatory origin. That is, the corresponding
codesare/znctionnlly equivalentin short-termmcmory. According to this rnodel,scquenccs
of items. should they be heard or articulated,are automaticallyrepresentedin short-ternr
memoryas streamsof events or objectsjoined by linkages. These linkages decay rapidly
unlessthey are rcfreshedby an amodal serial rehearsalprocess.The effects ol'irrelevanl
speechand articulatorysuppressionare assumcdto result from idcntical proccsses,namcly,
fi'ominterferenccbetweendifferent setsof order cuesbelongingto thc rcprescntationsof thc
inelevantmatedal and the sequenceto be remembered.According to this view, thc linkages
incorporated
within the irelevant streamsdisrupt the associationsbetwecnthe objccts reprcsentingthe list items, lcading to impaired serial rccall. Part of the O-OER model is the
clnnging-statehypothesis,which statesthat the magnitudeof disruption dependson thc
strengthof the linkagesbetweenelenrentsin the ineievant strcarn.which in turn dependson
thedegrecof changcbetweenadjacentitcms: Sequencesconsistingof dil'lerentevents(e.g.
heatingor articulatingthe syllablesA to G, a changing-state,sequeru:e)
producenroreiiisruptionthanrepetitionsof singleiterns(e.g.,hearingor articulatingonly the syllable A, a steaüslatesequeflce).As alreadymcntioned,the changing.stateaccountof the ISE has beenconfirmedin a rangeof studies.Concemingthe effectsof articulatorysuppression,thc inlluence
of changingstatehasbeendemonstrated
by Macken& Jones(i995, Exp. l-3). Using visual
presentation,
they showedthat repeatinga single syllablewas less disruptivethan articulating
asequence
(articulatingaloud.lwas
ofdifferent syllables.Additionaliy,vocalizedsuppression
moredisruptivethan mouthedsuppression(arliculating without producing audible sounds).
Furthermore,
the authorsinvestigatedthe combinedeff'ectsof lS turd suppression(Exp. 5).
Followingthe O-OER model, changingstateeffects producedby suppressionand inelevant
speech
result from identical rnechanismsand should thereforecancel each other out. More
180
General l)iscussion
The main findings o[ ExperimcntsI to 4 may be summarizedas follows. (l) h'rclevant
backgroundspeechproducesa reliable disruptionof serial recall both with visually and with
(2) The combinedeffectsofirrelevant speechand afticulatory
auditorily prcsenledsequences.
suppressiondiffer with respectto presentationmodality. When visual presentationis accompanied by articulatory suppression,the disruptive effect of in'clevant speechis complctely
the irrelevant speecheffect withstandssuppression.
abolished.With auditory pr-esentation,
(1987) were clearly confirmed.Furthermore(3),
Broadbent
Hanley
&
Tirus,tlte resultsof
undcr conditionsof auditorypresentation,the irrelevantspeecheffect persistswhen articulation is suppressedduring presentationand during a 10 secondsretention interyal. (4) For
visual prcsentation,the ISE survives a l0 secondsretentioninterval filled with articulatory
suppressionwhen rehearsalis possibleduring presentation.
'fhe
findings (l) and (2) are clearly in line with Baddeley'sassumptionthat speechgains
automaticand dircct accessinto the phonologicalstore, wheteaswritten stinruli have to be
1e-codedby meansof subvocalrehearsal.On the other hand, the finclings(3) and (4) do not
agreewell with thc standardphonologicalloop model.They indicatethat phonologicalcodes
can bc rnaintainedat least 10 secondswithout the help ofarticulatory rehearsal.
Before cliscussingtheseresults in detail, two altemativeexplauationsshouid be considerecl.First, it might bc proposedthat the disruptivecffects of irelevant speechfound in Experinrents1 to 3 do not result from interferencewith centralshort-termmemory codcs(aswe
proposed),but reflect perceptualmasking of the spokenitenrs during cncoding. This argument is not weakenedby the fact that pcrfect intelligibility of the items was cnsuredin all
of heard items can bc disn-rptedby backsoun<]conditions,since serial recall perforn.rance
grounclnoise even without an effect on identification (Surprenant1999).Thus, the encoding
of the auditorily presenteditems undernoisemight requiremore cognitiveefforl, leavingless
capacityfor cffective relrearsal.Flowever,in the experimentsreportedhere,broadbandnoise
was use{ insteadof a silent control condition. Several studieshave shown that speechis
usually rnorcrnaskedby steadystatenoisethanby a single contpetingspeaker(e.g.Larsby&
Arlingcr 1994;Hygge et al. 1992). Thus, if maskingwould play a dominantrole, one would
expectperformanccto be lower under noisc than under speeclr.Futlhcmrore,the rcsultsof a
recentexperimenton this matter (Schlittmeier,Hellbrück & Klatte, in prep.) arguc strongly
againstmasking as the causeof the disruptionin Experiments1 tt'r3. In this experiment,we
varied the tirning of the inelevant speech:For one group of subjects,the specchwa.splayed
continuously cluring auditory presentation,rehearsal,and recall of the lists. In the other
g.oup. the speechwas playedduring rehearsaland recall,but was turncd ofTduring presentation, therebypreventingany potential effect of masking.Silent and broadbandnoisecontrol
were also includedin both groups.The resultswere clear: Pcrformancewaslower
con<Jitions
in thc speechconditions, and this effect was the same in both groups"The tirning of the
speechhaclno eifect. Furthemlore,a significant changingstateeffect was found: Sequences
of different syllables produced more disruption than repctitions of a single syllable.The
t82
InelevantSpeechand Articulatory Suppression
M. Klatte, N. ke, J. Hellbrück
specifically,changingstatesuppressionshould abolishthe lSE, but steadystatesuppression
shouid not. ln line with this prediction, the magrritudeof the inelevant speecheffect depencledon the material to be articulated:Repeatedmouthing a single syllable during a 10sccondretentioninterval did not attenuatethe inelevant speecheffect, whereasrepeatingthe
sequence"A" to "G" led to a higtrly reducedirrelevantspeecheffect.
However, severalfindings of our study hardly reconcile with this model. First, in ExperimentsI and 2, the irrelevantspeecheffect on serial recall of visually presentedlists was
conrpletelyabolishedby steady-statearticulatorysuppression(continouslyrepeatinga single
syllable).Similarfindingshavebeenreportedpreviouslyby Milcs, Jones& Madden(1991),
Salam6& Batldeley (1982), and Hanley (1991).'fhese results indicate that changing-state
suppressionis not neccssaryto abolish the irrelevant speecheffect. Macken & Jonesargue
that in theseexperiments,not mouthedbut vocalizedsuppressionwas required.In their view,
vcr:alization produces stronger links between the iterns of an aticulated sequencethan
mouthingdoes(p. 441). Thus, rcpeatinga singleitem aloud might stresspotentialineguiarities in the articulatedstream,therebyincreasingits changesin state-Since thereare no independentcriteria for "changingstate" yet, this argumentis difficult to disprove.However,at
Ieastfor our study, it seemsunconvincingsince our participantswere instructedand trained
to a(iculate continuouslyand smootNy at a constantrate. Their performancewas very carefully monitored by the experimenterthroughoutthe session.In terms of the O-OER model,
our suppressionconditionswere surely steady-state.As Hanley (1997) points ont, the most
critical differencebetweenthe Macken & Jonesstudy and the studiesreporling abolition of
the ISE by articulatory suppressionis that in the former, suppressionwas confined to the
retentiorrinterval. During presentation,the subjectswere free to rehearse.Therefore,the
result of this study is clearly in line with the assumptionthat naming of visual items is a
preconditionfor the ISE to occur, and that this processis preventedby arlicuJatorysuppression.
Second,our study showsthat with visual presentation,the interactionbetweenirrelevant
speechand suppressiondependson the timing of the suppressionphase.Suppressionduring
presentationabolishesthe irrelevant speecheffect, whereassuppressionduring a rctention
interval leavesit unaffected.With auditory presentation,we consistentlyfound independent
effectsof inelevant speechand suppression.Thesefindings barely agreewith the assumption
that the effects of suppressionand irrelevant specchresuh from identical processes.Given
tlte amodal form of representation,modality-specificeffects should not occur. Further evidencequestioningthc equipotentialityhypothesisis providedby the studieson the combined
effects of phonologicalsimilarity and articulatorysuppressionmentionedabovc. According
to the O-OER-model,the phonological similarity effect is also a changing-stateeffect. It
arisesbecauselesschanging-state
informationis cmbodiedin sirnilarlists,resultingin weak
linkages between adjacentiterns (Jones& Macken 1995). Consequently,articulatory suppressionshouldinteractwith phonologicalsirnilarityand with inelevantspeechin precisely
the same way: The phonologicalsimilarity el'Iect should be abolishedunder conditionsof
changing-statesuppression.Contraryto this pediction, in the Richardsonet al. (1996) study,
neitherrepeatingaloud "uno, duo, tre" nor countingbackwardsby threesduring the retention
interval abolishedthe phonologicalsimilarity effect on visually presentedlists. On the other
hand, suppressionduring presentationdoes abolish the phonologicalsinrilarity effcct, even
(e.g.Munay 1968;tevy 1971,Baddeleyet al. 1984).
whenit is steady-state
t8l
These findings indicate that neither the interactionbetween suppressionand irrcievant
speechnor the interactionbetweensuppressionand phonologicalsimilarity dependcrucially
on the natureof the material to be articulated.Rather,they dependon the timing of the suppressionphaseand on the presentationmodality.uWhen suppressionis requiredduring visual
presentation,the effects of irrelevantspeechand similarity disappear.Supprcssionbctwecn
visual presentationand recall doesnot abolish theseeffects,even with long rctcntion intcrvals. With auditory presentation,the efl-ectsof similarity and irrelevant speechwithstand
In orderto accountfor thescfindings, a model which assumesmodality-spccific
suppression.
representations
without relying on tracedecayas the mechanisnrof {brgettingmight be morc
appropriate.Suchan accountis given by the featuremodcl (Nairne 1990).
The featuremodel assumesthat items are representedin merlory as lists of I'eatures,and
it relies on the distinctionbetweenprimary and secondarymemory. According to this model,
memorytracesconsist of two types of features.Modality-dependentfeaturesrepresentraw,
physicalaspectsof the iiems, whereasmodality-independentfeaturesrepresentabstractaspectswhich do not differ with presentationmodality. During recall, the partially degraded
tracesin primary memoly have to be matchedto the correct undegradedtracesin secondiuy
memoly. Forgetting in the feature model is basedon rctroactiveinterference,not on trace
decay.Modality-dependentfeaturesinterfere only with similar modality-dependent
featurcs.
modality-independentfeatures interfere only with similar modality-independentfeatures.
Within the model, tracesrepresentinghearditems containmore modality-dependent
featurcs
than tracesrepresenl"ing
visual itern. The fbaturemodel is particuliuly attraetivesince it is
capableto accountfor a wide range of immediatememory phenomena,including rnodality
andsuffix effects,effectsof temporalgrouping,zuticulatorysuppressionand phonemicsirnilarity, and it has recently been appiied to the effects of word length and ineievant speech
(Neath & Naime 1995; Neath, Suqprenant& I-eCompte 1998; Surprenant,lrCornpte &
Neath 1999;Neath 20ü)). The effects of suppressionand irrelevant speechare modclcd in
the sameway, that is, by adding noise to the moda.tity-independent
features("featureadoption"). This view has beensupportedby recentstudiesshowingthat, with respectto thc interactionswith phonemicsimilarity and word length,inelevant speechbehaveslike articuiatory
(Neathet a1.,1998;Surprenant,Neath& kCornpte 1999:but seealso Tremblay,
suppression
Macken& Jones2000,for a different view).
The featuremodel predictsthat with visual presentation,the ISE should be abolishedby
articulatorysuppression,which is clearly in line with thc result-sof Exp. I and2. On the other
hand,it also predictsthat the ISE should be abolishedwhen suppressionis confined to the
rchearsalphase,whereaswe fouud independenteffectsofIS and suppressionin this situaticln
(Exp. 4). Fut-thermore,given the assumptionthat both ineleviurt speechand suppression
affectonly modality-independent
features,it is not clear how the rnodelcould account(br the
persistenceof the ISE with auditory presentation.Another, morc general obstaclc of the
featureadoptionaccountof the ISE is that it cannot cxplain the disruptive eff'ectsof nonspeechsoundssuch as tones (Jones& Macken 1993)and music (Klatte & Hcllbriick 1993,
Klatte et al. 1995), since nonspeechsoundsobviously do not share modality-indcpcndcnt
l'ea(ures
with vcrbalitcms.
'
Furtherevidencequestioniugthe O-OER accountof articulatory suppressionhas been provided recently by
Meiser& Klaucr (1999).
184
185
M. Klatte. N. tre. J. Hellbrück
IrrelevantSpcechand Arliculatory Suppression
All together, some of the findings reported here are in line with the phonokrgical model,
and somc are not. However, the latter are neither in line with alternative models of thc ISE,
namely, the O-OER model and the feature model. Further research is needed to allow an
intcgrative account of the effects of irrelevant speech, articulatory suppression, and presentation rnodality, and thc various interactions between these phenomena.
20 Hygge, S., Rönnbcrg, J., Larsby, B. & Arlinger, S. (1992). Normal-hearingand hcaring-
2l
22
References
L1
1.
2.
3.
4.
,5.
6.
7.
8.
9.
10.
I l.
12.
13.
14.
15.
Baddeley,A.D. (1986).Working Memory. Oxford: Oxford UniversityPress.
Baddeiey,A.D. (1990).Human Mernory.LawrenceErlbaumAssociates.
Baddelcy, A.D. (1992).Is working memory working'l The fifteenth Bartlett lecture. The Quartcrly Journal of Experimental Psychology 44A, l-31.
Baddeley, A.D. (2000). The phonological loop and the irrelevant speechefI'ect: Sorne commentson Neath (2000).PsychonomicBulietin & Review 7,5M-549.
Baddeley, 4.D., Lcwis, V. & Vallar, G. (1984). Exploring the articulatory loop. Quarterly
Jounral of ExperimentalPsychology 36, 233-252.
Baddelcy,A.D., Thomson,N., Buchanan,M. (1975).Word length and the structureof shortterm memory. Journal ofVerbal Learning and Verbal Behaviour 14, 575-589.
Baddeley, A.D. Salam6, P. (1986). The unattended speech effect: Perception or memory?
Journaiof ExperimentalPsychology:Learning,Memory & Cognition 12,525-529.
Beaman,C.P.& Jones,D.M. (1997).Role of serialorder in the irrelevantspeecheffect.Testof
the changing-statehypothesis. Journal of Experirnental Psychology: Learning, Memory and
Cognition,23, 459-47l.
Brown, G.& Hulme, C. (1995). Modeling item length eflects in memory span: No rehearsa]
ncedcd?Joumal of Memory and Language34,594-621.
I3uchner,Ä., Imren, L. & llrdfelcler,E. (1996).On thc irrclcvanceof semanticinfonnationfor
the irrelevantspeecheffect.QuarterlyJoumalof ExperirnentalPsychology49A.765-779.
Burgess,N. & I litch, G. (1999).Memory for serialorder:A netrvorkrnodelof the phonological
loop and its timing. l'sychologicalReview 106,551-558.
Colle, H.A.& Welsh, A. (1976). Acoustic masking in primary rnemory. Journal of Verbal
Learningand VerberlBehavior,15, 17-3I .
Conrad,R. (1964). Acoustic confusionin imrnediatememory. British Joumal of Psychology
55,'t5-84.
Cowan,N. (1984).On kxrg and shortaudilory stores.PsychologicalBulletin 96,341-3"70.
Cowan, N., Wood, N.L., Wood, P.K., Keller, T.A'., Nugent,L.D. & Kelier, C.V. (1998).Two
separatevelbal processingratescontribute to short-termmemory span.Journal of Experimental
Psychology:General127, 141-160.
16. Ellermeier,W. & Helibrück, J. (1998). Is level irrelevantin "inelevant speech"?Effects of
loudncss,signal-Lo-noiseratio, and binaural Unmasking. Joumal of Experimental Psychokrgy:
Human Perceptionand Performance24, I-9.
I'7. Hanley, J.R. (1997).I)oes articulatorysuppression
rcn)ovethe irrelevantspeecheffect?Memory 5,423-431.
18. Ilanley, J.R. & Broadbent,C. (1987). The effectof unattendedspeechon serialrecallfollowing
auditorypresentation.
British Joumalof Psychology78,287-297.
19. Henson,R. (1998). Short-termmemory for serialorder: The start-endmodel. Cognitive Psyclrokrgy36,73-137"
24
25.
26.
2'7
28.
29.
impaircdsubjects'abilitytojust follow conversationin competingspeech,rcvcrsedspeechand
noise backgrounds.Journal ofSpeech and Hearing Rcsearch35,208-215.
Jones,D.M. (1993). Objects,streamsand threadsof auditory attention.In: Baddeley,A.l). &
Weiskrantz,L. (Eds.).Attention: Selection,Awarenessand Control. Oxford: Oxford Univcrsity Press.
Jones,D.M. (1995). The fatc ol the unattendedstimulus: Inelevant speechand cognition.
Applied CognitivePsychology9, 23-38.
Jones,D.M. (1999). The cognitivepsychologyol auditory distraction:The 199'7BPS Broadbent Lecture.British Journalof Psychology90,167-187.
Jones,D.M., Beaman,P. & Macken, W.J. (1996).The obiect-oricntedepisodicrccord nrodel.
In S.E. Gathercole(Eds.).Modcls of short-termmemory.PsychologyPlcss,an irnprint of Irrlbaum (UK) Taybr & FrancisLtd.
Jones,D.M. & Mackcn, W.J. (1993). Irrelevant tones protluce an irrelcvant speechcl'[cct:
lmplicationsfor phonologicalcoding in working memory. Journal of ExperirnentalPsychology: Learning,Memory and Cognition 19, 369-381.
Jones,D.M. & Mackcn, W.J. (1995). Phonologicalsimilarity in the irelevant speechef1'cct:
Within or between-streamsinilarity? Journal of Expcrimental Psychology: Learning, Memory
& Cognition21, 103-115,
Jones,D.M., Madden, C. & Miles, C. (1992). Privileged accessby irrelevant speechto shortterm mernory: The role of changing state.Quarterly Journal of Experimental Psychology 444.
64s-669.
Jones,D.M., Miles, C. & Page,i. (1990). Disruption of proofreadingby irelevant speech:
Elfects of attention,arousaior memory? Applied Cognitive Psychology 4, 89- 108.
Kiatte, M. & Hellbrück, J. (1993). I)er "lrrclcvant SpeechEffect": Wirkungcn von llintcrgrundschallauf das Arbeitsgedächtnis.Zeitschrift für Lärmbekärnpfung40 (4), 9 I -9U.
30. Klatte, M., Kilcher, H. & Hellbrück,J. (1995).Wirkungen der zeitlichenStruktur von Hinter-
31.
.) L.
f -).
34
35
36.
37"
grundschallauf das Arbeitsgedächtnis
und ihre theoretischenund praktischenlrnplikationcn.
Zeitschrift für ExperimenteilePsychologie42, 517-544.
Larsby, B. & Arlingcr, S. (1994). Speechrecognitionand just-follow-conversationtasks for
normal-hearingand hcaring-impaired
listenerswith differentmaskers.Audiology 33, 165-l'76.
Levy, B.A. (1971).Role of articulationin auditory and visual short-termmemory. Journalol'
Verbal Learning and Verbal Behaviour 10, 123-132.
LeCompte,D., Neely, C. & Wilson, I. (1997). Irrelevant speechand irelcvant tones: Thc
relative importance of speechto the irrelevant speecheffect. Journal of Experimental Psychology: Learning,Memory, and Cognition 23,472-483.
Lc Compte,D. & Shaibe,I). (1997).On thc irrclcvance
of phonological
similarity'tothc irrelePsychology50A, 100-l 18.
vant specchelTect.QuarlerlyJoumalof F,xperimental
Longoni, A.M., Aiello, A. & Richardson,J.T. (1993).Articulatory rehearsaland phonological
storagein working memory.Memory & Cognition21,11-22.
of the inner voice and the inner
Macken,W.J. & Jones,D.M. (1995).Functionalcharacteristics
ear: Single or double agency'l Journal of Experimental Psychology: Learning, Memory an<l
Cognitiorr 21, 436-448.
Meiser,T. & Klauer, K.C. (1999).Working memory and changingstatehypothesis.Journalol'
ExperimentalPsychology:Learning, Memory & Cognition 25,1212-1299.
186
M. Klatte, N. ke, J. Hellbrück
PsychologischeBeiträge,Band 44, 2002, S. 187-202
3 8 . Miies, C., Jones,D.M. & Madden, C. (-1991).I-ocus of the irrclevantspeecheff'ectin short-
39
40.
A1
A'
43
45.
46.
41.
48
49
50.
51,
52.
53.
54.
)).
56.
tenn memory. Journal of ExperimentalPsychology:Leaming, Memory and Cognition 17,5'78584.
Murray, D.J. (1968). Articulation and acousticconfusability in short-term mcmory. Journal of
ExperimentalPsychology7 8, 679-684.
Nairne, J.S. (1990). A featuremodel of imrnediatememory. Memory & Cognition 18,251269.
Nairne,J.S. & Kelley, M.R. (1999). Reversingthe phonologicaisirrilarity effect.Memory &
Cognition2'7,45-53.
Neath, L (2000). Modeling the effects of irelevant speechon memory. Psychonomic Bulletin
& Review7,403-423.
Neath, L & Nairne, i.S. (1995). Word-length effects in irnmediatemernory: Overwriting race
decaytheory.PsychonomicBulletin & Review4, 429-Ml.
Neath, I., Surprenant,A.M. & I-eCompte,D. (1998). Irrelevantspeecheliminatesthe word
lengtheffect.Memory & Cognition26,343-354.
Penney,C.G. (1989). Modality effects and the structureof shorl-term verbal memory. Mernory
& Cognition 17, 398-422.
of the phonologicaltrace
Richzrdson,J.T.E.,Longoni, A.M. & Di Masi, N. ( 1996).Persistence
in working memory. Current Psychology of Cognition 15, 557-581.
Salam6.P. & Baddeley,A.D. (1982). f)isruption of short-term memory by unattendedspeech:
Implications for the structureof working memory. Journal of Verbal Learning and Vcrbal Behaviour21, 150-164.
Salamd,P. & Baddeley, A.D. (1983). Differential effects of noise and speech on short-term
memory. In: Rossi, C. (Ed.). Proceedingsof the Fourth Intemational Congresson Noise as a
Pubtic Health Problem. Milan: Edition Techniche a Cura del Centre Ricerche e Studio Amplifon.
Salarn6,P. & Baddeley,A.D. (1987).Noise,unattendedspeechand short{erm memory.Ergonomics30, 1185-1194.
Salam6,P. & Baddeley,A.D. (1989). Effects of backgroundmusic on phonological short-term
memory. Quarterly Joumal of ExperimentalPsychology 414, 107-122.
Schlittmeier, S., Hellbrück, J. & Klatte, M. EfTectsof irrelevant soundson serial recall of heard
iterns: Disentanglingeffectsof masking, suffix, and changing state.Mmuscript in preparation.
Service, E. (1998). THd effect of word length on immediate serial recall depends on
phonological complexity, not articulatory duration. The Quarterly Journal of Experimental
Psychology5 | A, 283-304.
Surprenant,A. (1999). The effect of noise on memory lbr spoken syllables.lntemational Journal of Psychology 34,328-333.
Surprenant,A., LeCompte,D. & Neath, L (1999). Manipulationsof irelevant information:
Sutfix etfects with articulatory suppressionancl irrelevant speech.The Quarterly Journal of
ExperirnentalPsychology,52.4.
Surprenant,A., Neath,I. & LeCompte,D. (1999). Irrelevantspeech,phonologiczrlsimilarity,
and presentation modality. Memory 7 (4), 405- 420.
Tremblay,S., Macken, W.J. & Jones,D.M. (2000).Elinrinationof the word length effectby
irrelevantsoundrevisited.Memorv & Coenition28. 841-846.
Encoding of timbre, speech,and tones: Musicians vs. non-musicians
S'TEFAN
MüNZER'.StBraN BrRl' & TsorumsPecntllaNf
Summary
In tbree experiments,musiciansand non-musicianswere comparedwith regard to auditory intcrfcrencc
effects,whiie the kind ofmaterial (timbre, speech,and tones) and presentationrate were manipulatcd.'I'he
lcading question is whether the musicians' familiarity with the processingof tonal pitch gcncralizesto a
superiorityin analyzing auditory featuresof other kinds of matcrials. By the manipulation ol the prescntation rate it is attcmptedto obtain interferenceeffects at eeulyvs. later stagesof auditory processing.Rcsults
shorv that diffcrent materials oause diff'erent effects of presentation rate. For timbre, the effect was "linear",
meaning the slower the presentation rate the bettcr thc performance, with thc musicians outperlbrming the
non-musicians.For speech,an effect of prcscntationrate could only bc obtained with a very short stimulus
duration.At a critical point, musicianswere better than non-musiciansin the identification of speechsounds.
For tones,there was no effect of the presentationratc, but musicianswere far bctter than non-musiciansif
the stirnulus duration was sufficicntly long.
Kcy words: auditory processing,encoding,musicians,timbre, speech,tones
Introduction
What do musicians leam regarding auditory processingwhile undergoing extensivc
trainingin performingmusic?Musicians developa high familiarity with some auditory f-eatures.In particular, they are very experiencedin the processingof tonal pitch. It might be
askedwhcther there are advantagesin the analysisfor other auditory featuresas well (for
instance,auditoryfeaturcsof speechor timbre). Second,it might be a.skedat which stagesof
processingsuch advantagewill show up. According to Cowan (1984), a distinction can
be madebetweenshort vs. long auditory storage,the former reflecting an initial encoding
process,and the latter consistingof memory tracesfor auditory i'eatures.The presentwork
examinesiuterferenceeffccts for short vs. long auditory storageby a manipulationof the
presentation
rate and stimulusduration.To test for the specificity of possibleadvantageslbr
the musiciansas comparedto non-musicians,interferenceeffects for timbre, speech,and
tonalmaterialsaretested.
The interferenceparadigmthat is usedin the presentexperimentswas first establishedby
Deutsch(1970, 1915).The paradigmrequiresthe comparisonof two tones separatedby a -5
secinterval contaiiring6 interveningtones.The purposeof her researchwas (o demonstlate
'
Dr. Stefan Münzer. FraunhoferlPSl. Dolivostraße 15. D-64293 Darmstadt
'
Dr. StefanBerti, Institut für Allgemeine Psychologie,UniversitätLeipzig, Brühl 34-50, D^04129 Leipztg
'Dr.
ThomasPechmann,Institut für Linguistik, UniversitätLeipzig, Brühl 34-50, D-04129 Leipzig