Evaluative Conditioning of Pictures by Affective Olfactory and Auditory

C O G N IT I O N A N D E M O T I O N , 1999, 13 (6), 831±836

BRIEF REPORT Cross-modal Preference Acquisition: Evaluative Conditioning of Pictures by Affective Olfactory and Auditory Cues C a rien M . va n R eek u m , H elm a va n d en Berg, a n d N ico H . F rijd a University of A msterdam, the Netherlands

In th is r esea r ch , a cross-m od el p ar ad igm wa s cho sen to test th e hyp o th esis th at affect ive o lfa cto r y a n d au d it or y cu es pa ired wit h n eu t r al visu a l st im u li b ea r ing n o resem b la n ce o r logica l co n nection to th e a ffect ive cues ca n evoke p r eferen ce sh ifts in th ose st im uli. N eu tr a l visu a l st im u li o f ab st r a ct pa int ings wer e pr esent ed sim u lta neo usly wit h liked a n d disliked o d ou r s a n d so u n ds, with neu tr a l-neu tr a l pa irin gs se rv ing a s co n tr o ls. T h e resu lt s co n ® r m p revio us ® nd ings th at t he a ffective evaluat io n of p r evio usly n eu tr a l visu al st im u li sh ifts in t he direction o f con tingen tly pr esent ed affect ive au d ito r y st im u li. I n a d d itio n , th is r esea r ch sh o ws th e p r esen ce o f con dit io n in g wit h a ffective o d ou r s h avin g n o lo gica l con nect io n wit h th e p ict ur es.

INTRODUCTION T h e eva lu a tive co n dition in g (E C ) t h eo r y (e.g. L evey & M a r t in , 1987) p ro p o ses a fo r m o f p referen ce a cq u isitio n wh er eb y a ffect is t r a n sferred fro m a n h ed o n ic stim ulu s t o a n eu tr a l stimu lu s p resen t ed co n t ingen tly, ra th er t h a n b y exp ecta n cy lea r n in g, as is t h e ca se in cla ssica l co n d itio n in g. T h e cen t r a l ro le o f a ffect in E C h a s recen t ly b een b ro u gh t in t o q u estio n b y resea r ch wh ich su ggests th a t p referen ce shifts co u ld b e d u e t o t h e co n cep t u al h igh light in g o f sim ilar feat u res b et ween p aired stim uli (F ield & D avey, 1997). I n d eed , m a ny stu d ies yieldin g r esu lts co n sistent wit h t h e E C t h eo r y h ave used sim ilar stim uli o f t h e sa m e m o d a lity. A lth o u gh evid en ce fo r E C with p ercep tu a lly d issim ilar stimu li (e.g. Ba eyen s, E elen, Va n d en Bergh , & R eq uests fo r rep r in ts sh ou ld b e sen t to C a r ien va n R eek um , wh o se p resen t a dd r ess is F P SE , Section P sych o logy, U n iversiteÂd e G eneÁ ve, 9 ro u te d e D r ize, C H -1227 C a ro uge-G eneÁ ve, Swit zerla n d ; e-m a il: va n r eek u@ fa pse.u n ige.ch T h is st u d y wa s co m p leted by C. vR an d H . vd B. un d er th e su p er visio n of N .F. as a pa r t ia l fu l® llm ent of th e req u irem ent fo r a M a st er’s degree. We a re in d eb ted to D ick H a kvo o r t, Bert M o lenk a m p, N ico N o teba a r t , an d Ba r t va n Swo l fo r th e crea tio n o f th e h a rd - a n d so ftwa r e o f th e eq uipm ent , Ton Teerlin g fo r p rovid in g u s wit h the o do u r st im uli, F ra nk Ba eyen s fo r h is ad vice o n th e experim en t, a n d in p a r ticu la r, C ra ig Sm ith , Tom Jo h nst on e fo r th eir co n st r u ct ive com m en ts o n ea r lier versio ns o f t his m a nu scr ipt .

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C ro m b ez, 1989), a s well a s stimu li o f d ifferen t m o d a lities (e.g. Bierley, M cSween ey, & Va n n ieu w ker k , 1985) d o es exist, su ch stu d ies h ave p r im a r ily m a d e u se o f visu a l o r ver b al stimu li, with rela t ively litt le exa m in atio n o f ot h er sen sor y m o d a lities, su ch a s o lfactio n . T h e r elat ive ef® ca cy of o d o u r s co m p a red with o t h er sen so r y stimu li in a ffective lea rn in g is in t er estin g d u e t o t h eir lo wer accessib ility t o la n gu age o r a n a lytica l p ro cesses t h a n o th er (e.g. visu a l) stimu li. O d o u r s a re m o re o ften lab elled in t er m s o f t h eir h edo n ic q u a lities, su ggestin g at lea st t h at o d o u r s ar e p ro cessed in a less sem a n t ic m a nn er t h a n so u n d s o r visu a l stimu li (E h r lichm an & Ba sto n e, 1992), an d co u ld h en ce h ave a m o re direct , no n sem a n t ic effect o n a n eut r a l co n t ext u a l stimu lu s. I n a ser ies o f cro ss-m o d a l eva lua t ive co nd itio n in g exp erim en ts u sing o d o ur s as u n co n d itio n ed stim u li (U S), To d r an k , Byrn es, Wr zesn iewsk i, a n d Ro zin (1995) fo u n d t h at o n ly o d o u r s t h at co u ld p la u sibly b e con n ect ed to h u m a n s evo ked a sh ift in p r eferen ce fo r p er so n s d epicted in t h e p h o t ogr ap h s. T h is ® n d in g, a n d t h e fa ct t h a t t h e p a r t icipa n t s wer e exp licitly in str u ct ed t o p ay at t en t io n t o t h e o d o u r -p er son p a irin gs, co u ld a lter n a t ively b e in ter p ret ed in t er m s of a co n cep t u a l, overlap p in gfeat u res t r a n sfer m ech a n ism (F ield & D avey, 1997). T h e exp erim ent d escrib ed h ere wa s d esign ed to d et er m in e wh et h er a co n d itio n in g effect wo u ld o ccu r in a cro ss-m o d a l p a ra d igm wh ich m a d e u se o f o d ou r s an d so u n d s a s U S a n d p ict ur es o f abstr a ct p a in t in gs a s co n d itio n ed stimu li (C S), an d t o exa m in e wh et h er o d o u rs lea d t o la rger p reference sh ifts t h a n so u n d s. In a ® r st p h a se p a rt icipa n t s were asked t o ra te t h e p lea sa n tn ess o f ea ch item in a series o f r elat ively u n fa m iliar o d o u r s, so u n d s, a n d p ictu r es. O n t h e b a sis o f t he in d ividu a l r at ings, t h e m o st n eu tr a lly a n d a ffectively r at ed stimu li were selected fo r each p a r t icipan t . T h ese wer e u sed in a seco n d p h a se, in wh ich n eu t r a lly r at ed p ictu res (C S) were p r esen t ed simu ltan eo u sly wit h liked , d isliked , or n eu t r a l o d o u r s o r so u n d s (U S). I n a t hird p h a se, t h e p a r t icipa nt s re-eva lu a ted t h e p ictu r es. A n effor t wa s m a d e t o d iver t th e p a r t icipa n t s’ at t en tio n fro m t h e C S-U S co m b in a t io n s, by giving th em a co gn itively d em a n d in g t a sk b et ween t h e p resen t a tio n s o f t h e stim ulu s p a irin gs, t h u s m a k ing t h e p ar t icipa n t less likely t o elab o r at e a ct ively o n a p ossible link b et ween t h e stimu lu s p a irs.

METHOD T h e stu dy o rigina lly co n sisted o f t wo id en t ica l p a rt s, excep t t h at in th e seco n d p a r t t h e b a seline wa s p r eced ed wit h t h e su ccessive p resen t at io n o f a ll t h e stimu li to a cq u a in t th e p ar t icipa n t s wit h th e stim u li u sed. A s t h is d istin ct io n yield ed n o signi® ca n t m a in effect [F(1,44) = 1.7 06, P = .198], n o r in t er a ct io n effects [F(2,88) = 1.785, P = .17 4] o n co n d itio n in g, th e d a ta sets o f b o t h p a r t s were m erged a n d a re p r esen t ed la ter a s o n e exp erim en t .

Participants F ifty fem a le u n d ergr a d u a te stu d en t s of p sych o logy were recru ited , t heir p a r t icipa t io n p a r t ia lly fu l® lling co u r se r eq u irem en t s.

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Materials and Mode of Presentation N in et een co lo u r slides o f n o n ® gu r at ive p a int in gs o f relat ively u n k n own p a in t er s, 19 syn t h et ic so u n d effects a n d 19 o d o u r s co m p r ised o f o do u r -co m p on en t s o f 1 co sm et ic a n d fo o d p ro d u cts a n d ``essent ia l o ils’’ were ch o sen b a sed o n t h eir exp ected u n fam iliar ity (low fa m iliar ity wa s co n ® r m ed in a pilot stu dy with n ine p a r ticipa n t s). P a r t icipa n t s wer e seat ed in fro n t o f a M a cin t o sh L C I I I co m pu t er wit h a 14-inch co lo u r screen . So u n d s wer e pr esen t ed t h ro u gh h ea d p h o n es co n n ect ed t o th e so u n d o u t p u t of t h e co m p u t er via a n a m p li® er. E a ch o d o u r wa s p resen t ed wit h a d ispen ser wh ich d elivered co m p ressed a ir, sat u r at ed wit h t h e od o u r fro m a co n n ect ed ja r, t h ro u gh a 70 cm silicon t u b e t o a n o u t let at t a ch ed t o a m icrop h o n e b o o m o n t he h ead p h o n es, su ch t h a t t h e a ir ¯ owed lat er a lly b en ea th t h e n o str ils. T h e p ar t icipa n t s sco r ed t h eir evalu at io n o f ea ch stimu lu s o n a ver t ical b a r-rat in g sca le, wit h ab str a ct facia l exp ression s n ext t o t h e b a r p o r tr ayin g h ap p in ess, n eu tr a l, a n d u n h a pp in ess servin g a s referen ce p o in t s. R esp o n ses wer e tr a n sfo r m ed in t o in t eger va lu es b et ween + 100 (extrem ely p lea sa n t ) via 0 (n eu tr a l) t o 2 100 (extr em ely u n p lea sa n t ).

Procedure Baseline Phase. P a rt icipa n t s were t o ld t h at t h e m a in in t erest o f t h e exp er imen t wa s t he in ¯ u en ce of p lea san t a n d u n p lea sa n t stim u li o n t h e p ower o f co n cen t ra t io n a n d t h at in o r d er t o k n o w exa ct ly wh ich stim u li t h ey r ega rd ed as b ein g p lea san t o r u n p lea sa n t , a r at in g p ro ced u re wa s n eed ed . T h ey were t h en in str u ct ed h ow t o u se t he resp o n se sca le a n d t o rely o n t h eir ® r st im m ediat e an d sp o n t a n eo u s r ea ct io n s t o t he stim uli. Pa r t icipan t s were t hen fa m iliar ised with th e m o d e o f stimu lu s-p r esen ta t io n a n d r atin g, a fter wh ich t h e exp er im en t er left t h e ro o m a n d t h e exp er imen t co m m en ced . T h e 57 stimu li wer e ra n d o m ly p resen t ed fo r a d u r at ion o f 5 sec wit h an in t erstim ulu s int er va l (ISI ) o f 20 sec, du r in g wh ich o d o u r less co m p r essed a ir co n t inu ed t o ¯ o w. To avo id m ixtu r es o f o d o u r s, wh ich m igh t o ccu r wh en o d o u r s a r e p r esen t ed successively, o d o u r s were a lways fo llowed by eith er a so u n d o r a p ictu re. P a r t icip a n t s sco r ed t heir eva lu a tio n im m ed ia tely a fter p resen t at io n o f ea ch stim ulu s. A fter t h e b a seline p h a se, p a r t icipa n t s left t he ro om fo r 15 m inu tes, a cco m p a n ied by a n exp erim en ter. M ea n wh ile, fro m ea ch p a r t icip an t ’s stim ulu s r at in gs, t h e o t h er exp er im en t er select ed o n e h igh -rat ed o d o ur a n d so u n d , a nd o n e low-r at ed o d o u r a n d so u n d , w ith equ a l r a tin gs (with in 15 p o in t s) fo r t h e resp ect ive o d ou r s a n d sou n d s (avo id in g m o d a lity d ifferen ces ca u sed b y t h e selectio n o f U S or u n eq u a l va len ce). A lso, o n e n eu tr a l-ra ted o d o u r a n d n eu t ra l-ra ted so u n d were selected t o serve a s co nt ro ls. T h ese stimu li were co m b in ed wit h t h e six p ictu r es ra ted m ost clo sely t o zero t o fo r m six stim u lu s p a irs; o n e plea san t o do u r/sou n d w ith a n eu t r a l p ictu re, o n e un p lea sa n t o d o u r /soun d w ith a n eu t ra l p ictur e a n d o n e n eu t ra l o d o u r/ sou n d w ith a n eu t ra l p ictu r e. 1

A det ailed list of the st im u li u sed is ava ilab le on r eq u est.

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Acquisition Phase. T h e six stim u lu s p a irs were p r esen t ed eigh t t imes ea ch in r a n d o m o rd er, wit h t h e t wo p a ired stimu li bein g p resen t ed sim ulta n eo u sly, fo r 5 sec, wit h an I SI o f 40 sec in o r d er t o avo id m ixtu re o f o d o u r s (E .P. K oÈ ster, p er so n a l co m m u n icat io n , 1992). To keep p a r t icipan ts m en t a lly o ccu p ied d u r ing t h is I SI , a co n cen t r at io n t a sk , co n sistin g o f resp o n d ing t o a ssignm en t s su ch a s ``n a m e a s m a ny d ifferen t m u seu m s yo u k n ow a s p o ssible’’, wa s given a fter th e p resen t at io n o f ea ch stim u lu s p a ir. A b eep t o n e a fter 40 sec in d ica ted t h e n ext stimu lu s p a ir p r esen t a t io n, at wh ich t im e p a rt icipa n t s were t o sto p r esp o n d in g. Evaluation Phase. E a ch o f t h e 12 stimu li p r esen t ed p airwise in t h e co n d itio n in g p h a se wa s t h en p r esen t ed sep a r a tely a n d re-eva lu at ed , u sing exact ly t h e sa m e p ro ced u r e a s in t h e b aseline p h a se, with t h e ju sti® cat io n t o t h e p a r t icipa nt t h at so m e stimu li wer e p resen t ed o n ce m o r e t h u s en ab ling ``for m in g a goo d in d ex o f t h eir r esp o n ses’’.

RESULTS T h e da ta o f 4 o f t h e 50 p a r t icipa n t s co u ld no t be u sed , du e to eq u ip m en t failu re. A n exit in t er view co n ® r m ed th a t a ll p a r t icipa n t s b elieved t h e cover sto ry. T h e d a ta fro m a ll rem a inin g 46 p a r t icipa n t s were t h erefo re a n a lysed .

Data CS T h e m ea n r a tin gs o f th e o lfact o r y a nd a u d ito r y U S selected fo r p h a se 2 a re d ep icted in Tab le 1. T h e eva lu at ive respo n se-scor es t o t h e p ictu r es were a n alysed in a 2 3 3 3 2 M o d ality o f t h e U S (o d o u r/sou n d ) 3 Va len ce o f U S (liked /n eu t r a l/disliked ) 3 M ea su r ed (p r e-test/p o st-test) a n a lysis o f va r ia n ce with rep ea t ed m ea su r es o n t h e t h ree fa ct o r s. T h e in ter a ctio n effect o f Va len ce 3 M easu r em en t wa s sign i® ca n t [F(2,90) = 9.7, P = .0002]. T h e m ea n evalu at ive resp o n se sco res t o t h e C S p a ired wit h o d o u r -U S a n d so u n d -U S a re sh own in F ig. 1. TABLE 1 Mean Ratings of the Like, Neutral, and Disliked Odours and Sounds in Pre-test (Baseline Phase) and Post-test (Evaluation Phase) Pre-test M odality of US

Valence of US

Post-test

M

SD

M

SD

L iked N eu tr al D isliked

47 .26 0.16 2 78 .56

24.81 5.62 21.65

2 14.44 2 36.39

35 .94 42 .69 48 .02

L iked N eu tr al D isliked

53 .65 0.96 2 76 .80

23.05 8.00 24.45

42.00 3.78 2 51.63

33 .54 33 .31 35 .65

Odours 22.44

Sounds

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FIG. 1.

M ean eva lu at ive r esp o n se sco res o f th e pictu res in th e p r e-t est (wh it e b ar s) a nd p o st test (grey b a r s), p a ired w ith liked , neu tr a l, a nd d isliked od ou r s, a n d liked, n eut r a l, a n d disliked so u n ds.

P la n n ed co m p a r ison s o n t h e m ea n d ifferen ce sco res co n ® r m t ha t t h e eva lu at ive resp o n se sco res sh ifted in t h e p o st-test in t h e d irect io n o f t h e va lu es o f t h e U S. T he d ifferen ces in eva lu ative resp o n ses t o t h e p ictu res b et ween n eu t r a l-liked (N -L ) a n d n eu tr a l-neu t r a l (N -N ) p a irin g wer e sign i® ca n t, [F(1,45) = 6.861, P = .01 03] a n d b etween N -N a n d n eu t r a l-disliked (N -D ) p a irin g sh o wed a tr en d in t h e p r ed ict ed d irect io n [F(1,45) = 3.08 7, P = .0823]. T h e m ea n d ifferen ce sco r es o b t a ined a fter N -L p a irin g were h igh er t h a n t h e sco res a fter N -D p a iring [F(1,45) = 19.151 , P = .0001]. W ith resp ect t o t h e m o d a lities, it wa s hyp o t h esised t h at t he o d o u r s wo u ld h ave a stro n ger co n d itio nin g effect o n t h e p ictu res t h a n wo uld t h e so un d s, lea d in g t o a sign i® ca n t t h r ee-way in ter a ctio n effect fo r M o d ality 3 Va len ce 3 M ea su rem en t . Su ch a n effect wa s n o t fo u n d (F < 1), alth o u gh th e in t er act io n o f M od a lity 3 M ea su rem en t wa s signi® can t [F(1,45) = 4.267 , P = .045], im p lyin g so m e m o d a lity d ifferen ce in th e effects o f co n d itio n in g irresp ect ive o f t h e va len ce o f t h e U S. A s F ig. 1 in d ica t es, t h e sign i® ca n t in t era ct io n is d u e t o a stro n ger n egat ive co n d ition in g effect o f so u n d s a n d a stron ger p o sitive effect o f o d o u r s.

DISCUSSION T h e resu lts sh ow t h at liked a n d d isliked o d o u r s a n d so u nd s p a ired sim u lta n eo u sly with o r igina lly n eu tr a l p ictu r es evo ked p referen ce sh ifts fo r t h e p ictu r es, co n ® r m in g ear lier ® n d in gs o f eva lu a tive co n d itio n in g w ith U S a n d C S of d ifferen t sen so r y m o d a lities (e.g. Bier ley et a l., 1985). T h e hyp o t h esis t h at o d o u r s m igh t p ro d u ce a la r ger p referen ce sh ift d ue t o m o re h ed on ic, less co gn itive p ro cessing, wa s n o t sup p o rt ed . I m p o r t an tly, o u r resea r ch su ggests t ha t so u n d s a n d o d ou r s wh ich

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n eith er sh ar ed fea t u res wit h (ap a rt fro m t h eir co -o ccu rr en ce in t im e), n o r h a d a ny logica l co n n ect io n t o n eu t ra l visu a l stimu li co u ld n evert h eless estab lish a n eva lu a t ive respo n se fo r t h o se stimu li. T h is co n ® r m s p revio u s ® n d in gs by Ba eyen s et al. (1989) t h at eva lu a t ive co n d itio n in g ca n o ccu r wit h d issimilar stim uli, a n d a d d s to t h e cla im t h a t a ffect r a th er t h a n co n cep t u al m ech a n ism s p lays a key ro le in E C . M a nuscr ipt received 22 D ecemb er 1997 R evised m a nu scr ipt received 28 D ecemb er 1998

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