Auditory imagery and the poor-pitch singer

Transcription

1 Psychon Bull Rev (2013) 20: DOI /s BRIEF REPORT Auditory imgery nd the poor-pitch singer Peter Q. Pfordresher & Andre R. Hlpern Pulished online: 15 Ferury 2013 # Psychonomic Society, Inc Astrct The vocl imittion of pitch y singing requires one to pln lryngel movements on the sis of nticipted trget pitch events. This process my rely on uditory imgery, which hs een shown to ctivte motor plnning res. As such, we hypothesized tht poor-pitch singing, lthough not typiclly ssocited with deficient pitch perception, my e ssocited with deficient uditory imgery. Prticipnts voclly imitted simple pitch sequences y singing, discriminted pitch pirs on the sis of pitch height, nd completed n uditory imgery self-report questionnire (the Bucknell Auditory Imgery Scle). The percentge of trils prticipnts sung in tune correlted significntly with self-reports of vividness for uditory imgery, lthough not with the ility to control uditory imgery. Pitch discrimintion ws not predicted y uditory imgery scores. The results thus support link etween uditory imgery nd vocl imittion. Keywords Auditory imgery. Vocl imittion. Poor-pitch singing. Perception nd ction A criticl prolem tht ny vocl instructor must fce is n extension of the fct tht singer is unle to oserve lryngel motor movements used to control pitch. Even if one were le to oserve such movements (i.e., through lryngoscope), it is doutful tht such visul informtion would e s useful s, for instnce, eing le to oserve the hnd posture of n expert violinist. Vocl instructors therefore incorporte uditory nd visul imgery in pedgogy (e.g., imgine the pitch coming out of the top of your hed ). In the music eduction P. Q. Pfordresher (*) Deprtment of Psychology, University t Bufflo, 355 Prk Hll, Bufflo, NY 14260, USA e-mil: pqp@ufflo.edu A. R. Hlpern (*) Psychology Deprtment, Bucknell University, 1 Dent Drive, Lewisurg, PA 17837, USA e-mil: hlpern@ucknell.edu community, such use of uditory imgery is commonly referred to s udition (cf. Brodsky, Kessler, Ruinstein, Ginsorg, & Henik, 2008). The reserch reported here tested roder impliction of such prctices. Specificlly, if vocl imittion of pitch depends on uditory imgery nd is not just ided y it, individuls who re deficient with respect to vocl imittion, referred to here s poor-pitch singers (Hutchins & Peretz, 2012; Pfordresher & Brown, 2007; Welch, 1979), should show deficient uditory imgery ilities. We compred individuls performnce on simple vocl pitch imittion tsk (singing four-note monotone sequence) with responses on questionnire concerning the vividness nd controllility of uditory imges (the Bucknell Auditory Imgery Scle; henceforth, BAIS) nd pitch discrimintion ility. Theoreticlly, the present reserch rests on the ssumption tht vocl imittion of pitch relies on n inverse model of the uditory vocl system nd tht the contents of this inverse model re uditory imges (see Fig. 1). An inverse model is n internl model of perception/ction system tht guides motor plnning on the sis of the nticipted outcomes (gols) of the ction, similr to the ideomotor hypothesis of Willim Jmes (cf. Shin, Proctor, & Cpldi, 2010). Thus, the link from motor plnning to perceptul output opertes inversely, process tht my or my not e conscious. Becuse it must incorporte schemtic knowledge out sensorimotor ssocitions, the inverse model in Fig. 1 is controlled y motor plnning, s well s perceptul input (trget pitches). We propose (following Keller, 2012) tht mentl imges (here, uditory imges) re the contents of such n inverse model. Thus, in the context of pitch imittion, uditory imges function s ridge etween perception nd ction tht serve to guide plnning of lryngel movements. As such, limittions in uditory imgery my indicte poorly functioning inverse model, leding to poor pitch imittion ility. These theoreticl ssumptions re supported y recent neuroimging reserch, which suggests tht uditory imgery leds to ctivtion in motor plnning res (for

2 748 Psychon Bull Rev (2013) 20: Fig. 1 Representtion of the vocl pitch imittion system, including the hypothesized inverse internl model. (Adpted from Hickok, Houde, & Rong, 2011) reviews, see Hlpern, 2001; Ztorre & Hlpern, 2005). For instnce, recent study demonstrted enhnced ctivtion in premotor res nd sl gngli when prticipnts nticipted forthcoming uditory event, nd these ctivtions were positively correlted with self-reported vividness of imgery of the nticipted tune (Lever, Vn Lre, Zielinski, Hlpern, & Ruschecker, 2009). Thus, uditory imgery my llow one to crry out the kind of sensorimotor trnsformtions tht llow inverse modeling of perception nd ction (cf. Herholz, Hlpern, & Ztorre, 2012; Ztorre, Hlpern, & Bouffrd, 2010). Behviorlly, pst reserch hs shown tht etter uditory imgery ility fcilittes consistency of expressive timing in performnce (Clrk & Willimon, 2011) nd more effective prctice (Brown & Plmer, 2012; Highen & Plmer, 2004). Thus, if vocl imittion of pitch depends on uditory imgery, deficiencies in the vocl imittion of pitch mong poor-pitch singers should e correlted with deficiencies in uditory imgery. Poor-pitch singing is production-relted deficit chrcterized y generl tendency to mistune solute pitch, compression of intervl size for reltive pitch, nd imprecision of pitch production (for reviews, see Berkowsk & Dll Bell, 2009; Pfordresher & Mntell, 2009; Welch, 1979). Poor-pitch singers typiclly do not demonstrte deficient pitch discrimintion ilities, nor do they pper to e deficient with respect to vocl motor control outside the context of imittion. Thus, it hs een hypothesized tht deficient inverse model of the uditory vocl system my cuse poor-pitch singing (Pfordresher, 2011). We collected self-reports of uditory imgery ility to test this hypothesis directly. Method Prticipnts Prticipnts (N = 138) were recruited from the introduction to psychology suject pool t SUNY Bufflo. Dt reported here come from prescreening procedure conducted ech semester (first descried y Pfordresher & Brown, 2007, Experiment 2). Seventy-six prticipnts (55 %) were femle, 61 were mle, nd 1 prticipnt elected not to report gender. The men ge ws 19 yers (rnge: 18 27). Sixty-three prticipnts (46 %) reported ntive lnguge other thn English; of these, 33 (24 %) reported first lerning tone lnguge (Mndrin, Vietnmese, or Cntonese). We recorded musicl ckground using reported yers of experience, summed cross ll instruments nd voice. Across prticipnts, the men yers of summed experience reported ws 2.9 yers (rnge: 0 43; the prticipnt reporting 43 yers of trining hd 10 or more yers of experience with three instruments nd voice). A totl of 37 prticipnts (27 %) reported 5 or more yers of experience nd were considered musicins (men for this group = 8.8 yers). The smple ws predominntly nonmusicin; most prticipnts (N = 101, 73 %) reported fewer thn 5 yers of musicl experience, nd 72 prticipnts (52 %) reported no experience whtsoever. Apprtus Prticipnts were recorded while sitting inside Whisper Room SE 2000 recording ooth. Instructions nd stimuli were delivered to prticipnts vi pir of Sennheiser HD 280 Pro hedphones. Prticipnt recordings were mde using Shure PG58 microphone. Sound levels were controlled using Lexicon Omeg I/O ox. The experiment ws conducted on 3.4-GHz PC running Windows XP. The experimentl procedure ws run using MATLAB scripts (The Mthworks, Ntick, MA). Procedure Prticipnts were run in single session tht took pproximtely 30 min. The session ws divided into the following locks, run in the order in which they re descried. Wrm-up The procedure egn with series of wrm-up trils consisting of extemporneous speech ( descrie wht you hd for dinner lst night ), reding pge of text, nd singing fmilir tune. Prticipnts were then sked to produce vocl sweeps: continuous chnge in pitch from the lowest note n individul cn comfortly sing up to the highest note he or she cn comfortly sing nd then ck down. Finlly, prticipnts produced single sustined pitch tht ws comfortle for them to produce (descried s note the prticipnt my use to strt singing song). The experimenter then identified the nerest pitch on the C-mjor scle (these pitch clsses were used to simplify the procedure), nd this comfort pitch ws used s the sis for experimentl trils.

3 Psychon Bull Rev (2013) 20: Vocl imittion Following wrm-up trils, six experimentl vocl imittion trils were completed. On ech tril, the prticipnt first listened to sequence of four identicl pitches ( monotone sequences) nd then reproduced this sequence y singing on the syllle l. Pitches on the first nd lst trils were equl to the prticipnt s comfort pitch. Trils 2 nd 3 included pitches tht were two nd four scle steps, respectively, higher thn the comfort note, using pitches from the C-mjor scle. Trils 4 nd 5 comprised pitches tht were two nd four scle steps elow the comfort pitch, respectively, lso drwn from C-mjor pitches. Following ech tril, the results of MATLAB pitchtrcking lgorithm were displyed on the screen, showing the prticipnt s produced f0, s well s oundries representing devitions of ±100 cents surrounding the trget f0. This criterion ws sed on ctegoriztions of poor-pitch singers reported elsewhere (cf. Dll Bell, Giguere, & Peretz, 2007; Pfordresher & Brown, 2007; Pfordresher, Brown, Meier, Belyk, & Liotti, 2010). The experimenter coded ech tril s in tune if the mjority of smpled f0 vlues were within these oundries nd out of tune if not. This procedure ws initilly dopted to llow esy ctegoriztion of prticipnts for inclusion in other experiments s ccurte or poor-pitch singers; here, we dopt these ctegoriztions s n dditionl mesure to coustic nlyses of performnces (lso reported). Pitch discrimintion On ech pitch discrimintion tril, prticipnts herd two pure tones nd reported which tone ws higher in pitch. Pitches were rrnged round stndrd frequency of 524 Hz (C5), nd could differ from this stndrd y plus or minus 13, 25, 50, or 100 cents or did not differ. Prticipnts were presented with four trils from ech condition, two ech of scending nd descending chnges (plus four no-chnge conditions), in rndom order. Due to temporl constrints nd equipment filures, pitch discrimintion dt were not otined for 9 prticipnts. Auditory imgery Finlly, prticipnts completed the BAIS. 1 This instrument comprises 28 items divided eqully into suscles for the vividness of uditory imgery (e.g., the vividness of hering trumpet ply Hppy Birthdy ) or control of uditory imgery (e.g., the ese with which one cn chnge the uditory imge of choir of children into choir of dults). Items proe musicl, verl, nd environmentl sounds. All 1 This questionnire is ville on request from the second uthor. responses were mde on scle of 1 7, with 7 indicting more vivid or esier to chnge. Becuse the BAIS ws dministered lst, time constrints prevented some prticipnts from completing it: 120 (87 %) completed the vividness suscle (which ppered first), nd 114 (83 %) completed oth suscles. Results BAIS responses Anlyses focused on whether individul differences in vocl imittion re relted to self-report mesures of uditory imgery, mesured y the BAIS. Responses to the BAIS were highly relile (Cronch s lph for ll items =.910, for the vividness suscle =.833, for the control suscle =.909). The men imgery score cross oth suscles (from 1 to 7) ws 4.78 (SD = 1.05). Men rtings of vividness (M =4.90, SE = 0.09) were slightly ut significntly higher thn rtings of control (M =4.66,SE = 0.11), t(113) = 2.72, p <.01. Responses on the suscles (verged cross items) were significntly correlted, r(112) = 0.50, p <.01. Vocl imittion Figure 2 shows the reltionship etween the percentge of trils sung in tune (sed on the procedure descried erlier) nd the men rting given for ech prticipnt on the vividness suscle of the BAIS. There ws significnt positive correltion, r(118) =.28, p <.01,s predicted. The corresponding reltionship etween performnce nd the imgery control suscle of the BAIS, showninfig.2, ws positive ut ws not significnt, r(112) =.11, p >.10. In ddition to ctegoriztion of trils in tune, we lso mesured the men solute devition of produced from trget f0 cross ech tril. These production mesures were highly correlted, r(118) =.85, p <.01, ut differed with respect to the tretment of intontion s ctegoricl (percentge of trils in tune) or continuous (pitch devition). As with the percentge of trils in tune, men solute pitch devition scores were significntly correlted with the vividness of uditory imgery, r(118) =.24, p <.01, ut were not significntly correlted with control of imgery, r(112) =.08, p >.10.In order to simplify further nlyses, we determined which mesure most effectively predicted the vividness of uditory imgery y regressing vividness rtings on oth the percentge of trils in tune nd men solute pitch error. The multiple regression ws significnt (p <.01). A prtil correltion nlysis indicted tht neither mesure of production ccounted for significnt portion of the vrince independently of the other (lthough proportion

4 750 Psychon Bull Rev (2013) 20: Fig. 2 Sctterplots displying the reltionship etween the men percentge of trils (out of six) sung in tune; x-xis), nd men responses on the BAIS questionnire concerning vividness of uditory imgery (, y-xis) or ility to control uditory imgery (, y-xis). Ech plot includes the lestsqures regression line. Ech element on sctterplot represents single prticipnt of trils in tune yielded mrginlly significnt effect, p =.07), ering out the sustntil collinerity of these predictors. At the sme time, the stndrdized coefficient ws considerly lrger for the proportion of trils in tune (ß =.29) thn for solute pitch error (ß =.02). On the sis of its lrger effect size, we decided to use proportion of trils in tune for ll susequent nlyses. The nlyses reported ove verged cross ll six imittion trils for mesures of production, in order to enhnce sttisticl power. However, performnce within ech condition (pitch height of the modeled pitch) is of interest, s well s whether correltions etween imittion nd imgery vry cross conditions. Figure 3 shows the percentge of trils sung in tune, ggregted cross prticipnts, for ech tril. As cn e seen, performnce declined considerly for trils 4 nd 5, which were oth lower thn the comfort pitch (see secondry x-xis). Differences cross conditions were significnt ccording to chi-squre test, χ(5) = , p <.01. Of greter interest is whether the reltionship etween imittion ccurcy nd imgery self-reports vried cross positions. Point-iseril correltion coefficients for these reltionships re shown in Fig. 3 for oth BAIS suscles. Correltions with vividness were significnt cross ll trils; y contrst, correltions with rtings of control were significnt only for tril 1. Pitch discrimintion The focus of the present reserch is on the role of uditory imgery in production. However, it is lso possile tht individul differences in pitch discrimintion ility (which typiclly does not led to poor pitch singing, s ws discussed erlier) re correlted with individul differences in uditory imgery (lthough relile ctivtion of the primry uditory cortex during uditory imgery hs typiclly not een found; Ztorre & Hlpern, 2005). As such, we ssessed whether overll performnce on the pitch discrimintion tsk correlted with responses on ech BAIS suscle. First, we correlted BAIS scores with men pitch discrimintion ccurcy cross ll conditions. Figure 4 nd plot reltionships of ech suscle of the BAIS (s in Fig. 2) with the percentge of trils on Fig. 3 Percentges of trils sung in tune (cross prticipnts) s function of tril numer (upper pnel). The lower pnel shows n exmple of the pitches prticipnt my e sked to imitte on ech tril, given comfort pitch of G3 (see lso secondry x-xes from oth upper pnels). Point-iseril correltions etween ccurcy within single tril (dichotomous x vrile) nd men response on ech suscle of the BAIS (y vrile). This plot shows correltion coefficients (y-xis of plot) seprtely for ech imittion tril (x-xis of plot) nd suscle

5 Psychon Bull Rev (2013) 20: Fig. 4 Sctterplots displying the reltionship etween the men percentges of trils on which prticipnts correctly discriminted pitch chnges (x-xis), nd men responses on the BAIS questionnire concerning vividness of uditory imgery (, y-xis) or ility to control uditory imgery (, y-xis). Ech plot includes the lest-squres regression line. Ech element on sctterplot represents single prticipnt which ech prticipnt correctly discriminted the direction of pitch chnge. The reltionship etween men ccurcy in perceptul discrimintion nd the vividness of uditory imgery ws only mrginlly significnt, r(118) =.13, p=.07, ut did rech significnce for the correltion etween pitch discrimintion nd control of uditory imgery, r(112) =.14, p <.05. A further multiple correltion nlysis ws used to determine whether imittion ccurcy predicted rtings of vividness independently of perceptul discrimintion ility. The regression of vividness on the predictors percentge of trils sung in tune nd men ccurcy of discrimintion ws significnt (p <.01), ut prtil correltion nlysis showed significnt correltion only for the percentge of trils sung in tune (p <.01), wheres the prtil correltion etween pitch discrimintion nd vividness ws not significnt (p =.30). As we did in our nlyses of production, we lso nlyzed pitch discrimintion performnce, nd correltions with BAIS, cross different experimentl conditions. Figure 5 shows men ccurcy on pitch discrimintion s function of pitch seprtion (note tht the 0-chnge condition constitutes ctch trils ) nd direction of the pitch chnge. A within-sujects nlysis of vrince yielded significnt min effect of pitch seprtion, F(4, 516) = , p <.01, min effect of pitch direction, F(1, 129) = , p <.01,nd significnt seprtion direction interction, F(4, 516) = 4.67, p <.01. The min effect of seprtion reflects the fct tht performnce incresed relily with incresing pitch seprtion, ws t chnce for the no-chnge condition (M =.49, SE =.02), nd ws highly ccurte, lthough not t ceiling, for the 100-cent chnge (M =.94,SE =.01). The min effect of direction reflects slight is to report descending pitches (pprent in the no-chnge condition) tht ws enhnced for resons we cnnot explin in the 25-cent chnge condition, leding to the interction. We next consider whether the reltionship etween perception nd imgery self-reports vries with the mgnitude of the pitch chnge (the most criticl fctor in the pitch discrimintion tsk). Person correltion coefficients s function of pitch chnge condition nd the two suscles of the BAIS re shown in Fig. 5. Note tht ech pitch chnge condition for single prticipnt yields four dt points (two scending nd two descending conditions). As cn e seen, correltions were stronger for the lrger pitch chnge conditions nd were mximl for oth BAIS suscles in the 50-cent chnge condition, possily reflecting the moderte difficulty level of this condition. Correltions Fig. 5 Percentges of correct discrimintion s function of the mgnitude of pitch chnge nd direction of pitch chnge (for the nochnge condition, the y-xis simply reflects percentge of responses tht re either scending/descending). Error rs represent 1 SE. Person correltions etween ccurcy within single chnge mount condition (x vrile) nd men response on ech suscle of the BAIS (y vrile). This plot shows correltion coefficients (y-xis of plot) seprtely for ech chnge mount (x-xis of plot) nd suscle

6 752 Psychon Bull Rev (2013) 20: with the vividness suscle were significnt for the 50- nd 100-cent chnge conditions, wheres no correltions with the control suscle were significnt. Third vriles Becuse we included oth musicins nd nonmusicins in our smple, we next considered the degree to which musicl experience ccounts for BAIS responses, s well s vocl imittion ccurcy. Not surprisingly, totl yers of musicl experience correlted significntly with the proportion of trils sung in tune, r(118) =.29, p <.01, nd vividness rtings, r(118) =.30, p <.01. We were interested in whether BAIS responses predict production ccurcy independently of musicl experience. A multiple regression nlysis of vividness rtings with predictor vriles of percentge of trils sung in tune nd yers of musicl experience ws significnt (p <.01), nd prtil correltion nlysis showed tht ech predictor ccounted for independent portions of the vrince (p <.05 for proportion of trils in tune, p <.01 for yers of musicl trining). Another potentil source of vriility in the dt hs to do with linguistic ckground, given recent evidence suggesting some dvntges for tone lnguge spekers in vocl pitch imittion tsks (Pfordresher & Brown, 2009). However, tht study found no dvntge for tone lnguge spekers in the imittion of monotone sequences like those used here. Likewise, nlyses of imittion ccurcy cross tone nd nontone lnguge spekers here yielded no differences, nor did comprisons of groups for BAIS suscles nd the perceptul discrimintion tsk (note tht evidence for tone lnguge dvntge for simple pitch discrimintion is mixed; Bidelmn, Gndour, & Krishnn, 2011). inverse modeling pproch to sensorimotor ehvior. It is prticulrly interesting in this context ecuse of the covert nture of singing (motor feedck is hrd to oserve). Auditory imgery might underlie other kinds of covert ehvior, such s cquiring foreign ccent. Although similr trends were seen in correltions with oth the vividness nd control suscles of the BAIS, only the vividness scle yielded significnt reltionships. This dissocition my reflect the kind of deficit present mong poor-pitch singers. Wheres the vividness suscle concerns one s ility to generte n uditory imge, the control suscle involves oth the genertion nd mnipultion of n uditory imge. The fct tht vividness rtings yielded the strongest correltions with vocl imittion ility suggests tht poor-pitch singing involves n imgery deficiency t very sic level. We note tht lthough the uditory imgery scores were generted y self-report, our confidence in the vlidity of this mesure is enhnced y the precision with which only one of the suscles correlted with only the one hypothesized uditory vocl ility. Comined with the prior evidence tht this scle predicts neurl ctivity on voxel-yvoxel sis (Herholz et l., 2012; Ztorre et l., 2010), we suggest tht prticipnts cn mke self-judgments of the internl trit of imgery ctivity in wy wholly dequte for systemtic investigtion. Acknowledgments Peter Q. Pfordresher, Deprtment of Psychology, University t Bufflo, Andre R. Hlpern, Deprtment of Psychology, Bucknell University. This reserch ws supported in prt y NSF grnt BCS We thnk Timothy Hurd for vlule comments on n erlier version of the mnuscript, nd we thnk Esther Song nd Reecc Bergemnn for ssistnce with dt collection. Discussion We report evidence of n ssocition etween self-reports of the vividness of uditory imgery (mesured using the BAIS) nd the ccurcy with which prticipnts could imitte pitch through singing. This ssocition ws independent of musicl experience, height of the imitted pitch, nd pitch discrimintion ility. These results support our hypothesis tht vocl imittion relies on uditory imgery. As ws descried erlier, neuroimging evidence suggests tht uditory imges prime motor plnning res nd, thus, provide mechnism for the inverse modeling of perception nd ction reltionships tht my e used in contexts like vocl imittion. Our dt suggest tht poor-pitch singers my fil to generte the kind of (vivid) uditory imges tht cn e used to guide motor plnning (Herholz et l., 2012; Ztorre et l., 2010). Identifying this construct s mediting the perception ction link oth supports nd extends the References Berkowsk, M., & Dll Bell, S. (2009). Acquired nd congenitl disorders of sung performnce: A review. Advnces in Cognitive Psychology, 5, Bidelmn, G. M., Gndour, J. T., & Krishnn, A. (2011). Musicins nd tone-lnguge spekers shre enhnced rinstem encoding ut not perceptul enefits for musicl pitch. Brin nd Cognition, 77, Brodsky, W., Kessler, Y., Ruinstein, B. S., Ginsorg, J., & Henik, A. (2008). 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