1989 Eich & Metcalfe 1989 Mood Dependent Memory for Internal Versus External Events

7/30/2019 1989 Eich & Metcalfe 1989 Mood Dependent Memory for Internal Versus External Events

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Journ al of Exp erime nta l Psychology: Copyright 1989 by the Am erican Psychological Associa tion, Inc .Learn ing, Me mo ry, and Cognit ion 0278-7393/89/$00.751989, Vol . 15, No. 3 , 443-455

Mood Dependent Memory for Internal Versus External EventsEric EichU n i v e r s i t y o f B r it i sh C o l u m b i aV a n c o u v e r , B r i t i s h C o l u m b i a

Janet MetcalfeU n i v e r s i t y o f C a l i f o r n ia , S a n D i e g o

Events that originate through internal mental operations such as reasoning, imagination, andthought m ay be m ore co lored by o r connec ted to one ' s curren t moo d than a re those tha t emana tefrom e xternal sources. If so, then a shift in m ood state , between the occasions of event encodingand even t re t r ieva l, shou ld have a g rea te r adverse im pac t on one ' s me mory fo r in te rna l than fo rexternal events . T o investigate this inference, a series of s tudies w as conducted th at relied on acon t inuous m us ic techn ique to m odify mood , an d on the genera te / read p rocedures dev ised bySlam ecka and G raf (1978) to dis tinguish interna l from exter nal events . Considered collectively,the results suggest that in ternal even ts are less likely than external events to be recalled after ash if t in mo od s ta te. Discuss ion cen te rs on bo th the empir ica l l imita t ions and theore t ica limp lication s of the present results , as well as on prospects for future research.

T h i s a r t i c l e a d d r e s s e s t h e s t a t e d e p e n d e n t e f f ec t s o f m o o d so n m e m o r y f o r i n t e r n a l a s o p p o s e d t o e x t e r n a l e v e n t s . T op a r a p h r a s e J o h n s o n a n d R a y e ( 1 9 8 1 ) , i n t e r n a l e v e n t s a r et h o s e t h a t o r i g i n a t e t h r o u g h m e n t a l o p e r a t i o n s s u c h a s r ea -s o n i n g , i m a g i n a t i o n , a n d t h o u g h t , w h e r e a s e x t e r n a l e v e n t sr e f er t o s e n s o ry s t i m u l i t h a t a r e a p p r e h e n d e d , o r b r o u g h t i n t oa w a r e n e s s , v i a t h e p r o c e s s e s o f p e r c e p t i o n . T h o u g h t h e d i s -t i n c t i o n i s n e i t h e r r i g id n o r p r e c i s e - - t h o u g h t t e n d s t o r e f l e ctp e r c e p t i o n , a n d p e r c e p t i o n , t h o u g h t - - d i f f e r e n c e s b e t w e e nm e m o r i e s d e r i v e d p r i n c i p a l l y f r o m i n t e r n a l v e r s us e x t e r n a ls o u r c e s d o e x i s t . F o r i n s t a n c e , s e v e r a l s t u d i e s h a v e s h o w n t h a tt h e p r o b a b i l i t y o f r e c a l l i n g o r r e c o g n i z i n g a w o r d i s g r e a t e r i ft h e w o r d h a d b e e n g e n e r a t e d r a t h e r t h a n r e a d b y s u b j e c t s( e .g . , S l a m e c k a & F e v r e i s k i , 1 9 8 3; S l a m e c k a & G r a f , 1 9 78 ) .A l s o , w h e n a s k e d t o e s t i m a t e t h e f r e q u e n c y w i t h w h i c h t h e yh a d e i t h e r a c t i v e l y g e n e r a t e d o r b e e n p a s s i v e l y p r e s e n t e d w i t ha w o r d , s u b j e ct s a p p e a r m o r e a t t u n e d t o t h e r e l a ti v e n u m b e ro f g e n er a t i o n s t h a n t o t h e r e l a ti v e n u m b e r o f p r e se n t a t i o n s( J o h n s o n , T a y l o r , & R a y e , 1 9 7 7 ; R a y e , J o h n s o n , & T a y l o r ,1 98 0) . A n d a l t h o u g h t h e p r i o r p r e s e n t a t i o n o f a w o r d h a s aw e a k e f f ec t o n t h e l a t e r e st i m a t i o n o f h o w o f t e n t h a t w o r dh a d b e e n g e n e r a t e d , p r i o r g e n e r a t i o n s s t r o n g l y b i a s s u b s e -q u e n t j u d g m e n t s a b o u t p r e s e n t a t i o n s ( J o h n s o n e t a l . , 1 9 7 7 ;R a y e e t a l ., 1 9 8 0 ) . T h e s e r e s u l t s su g g e s t t h a t , a s R a y e a n d h e ra s s o c i a t e s ( 1 9 8 0 ) h a v e r e m a r k e d , t h e r e i s s o m e t h i n g s p e c i a la b o u t m e m o r y f o r i n t e rn a l l y g e n e r a t e d e ve n t s.

T h e r e m a y b e s t i ll a n o t h e r r e s p e ct in w h i c h m e m o r y f o ri n t e r n a l e v e n t s i s s p e c i a l . R e c e n t r e s e a r c h i n t h e a r e a o f a f f e c ta n d c o g n i t i o n i n d i c a t e s t h a t e x p e r i m e n t a l m a n i p u l a t i o n s o fm o o d e x e r t p o w e r f u l e f fe c ts o n t h e p e r f o r m a n c e o f s o m e , b u tn o t a l l , t y p e s o f t a sk s . A m o n g t h e t a s k s th a t s e e m m o s t

Prepara t ion o f th is a r t ic le was a ided by G ran ts U0298 and A0505from the Natural Sciences and Engineering Research Council ofCanada to Eric Eich and Janet Metcalfe , respectively, and by theadv ice and ass is tance p rov ided by Jenn ife r C ampbe l l , J ack ie DiGeso ,Hea the r McEachern , Jack Rachman, J im Russe l l , Pe te r Suedfe ld ,and A ins l ie Win te r .Correspondence concern ing th is a r t ic le shou ld be addressed to EricEich , Department o f Psychology , Univers i ty o f Bri t ish Columbia ,Vancouver , Bri tish Co lumbia , Canada V6T 1Y7.

s e n si t iv e t o m o o d m a n i p u l a t i o n s a r e w o r d a s s o ci a t io n , n a r -r a t i v e c o n s t r u c t i o n , a n d i n t e r p e r s o n a l a s se s s m e n t ( s e e B l a n e y ,1 9 8 6 ; B o w e r , 1 9 8 1 ; I s e n , 1 9 8 4 ; T e a s d a le , 1 9 8 3 ) . T h u s , fo re x a m p l e , a n g r y p e o p l e p r o d u c e a n g r y a s s o c i a t i o n s , t e l l h o s t i l es t o r i e s , a n d t e n d t o f i n d f a u l t i n o t h e r s . A m o n g t h e l e a s ts e n s i ti v e t a s k s a r e S t r o o p i n t e r f e r e n c e , s p e e c h s h a d o w i n g , a n dp e r c e p t u a l i d e n t i f i c a t i o n ( s ee B l a n e y , 1 9 8 6; B o w e r , 1 9 85 ) . B yw a y o f i l l u s t r a t i o n , G e r r i g a n d B o w e r ( 1 9 8 2 ) f a i l e d t o f i n d ar e l i a b l e e f f e ct o f h y p n o t i c a l l y i n d u c e d e l a t i o n o r a n g e r o nt a c h i s t o s c o p i c t h r e s h o l d s f o r n a m i n g p l e a s a n t v e r s u s u n p l e a s -a n t w o r d s .

O n e p l a u s i b l e i n t e r p r e t a t i o n o f t h i s p a t t e r n o f r es u l t s i s t h a tt a s k s th a t a r e n o t p a r t i c u l ar l y se n s it i ve t o e x p e r i m e n t a l m o d -i f i ca t i o n s o f m o o d a r e t ho s e t h a t p l a c e a p r e m i u m o n t h ea u t o m a t i c o r d a t a - d r i v e n p e r c e p t i o n o f external e v e n t s . I nc o n t r a s t , t a s k s t h a t a r e e s p e c i a l l y s e n s i t iv e a r e o n e s t h a t i n -v o l v e t h e internal p r o d u c t i o n o f w h a t J o h n s o n a n d R a y e( 1 9 8 1 , p . 70 ) c a l l " c o t e m p o r a l t h o u g h t . . . t h e s o r t o f e l a b o -r a t i v e a n d a s s o c i a t iv e p r o c e s s e s t h a t a u g m e n t , b r i d g e , o r e m -b e l l i s h o n g o i n g p e r c e p t u a l e x p e r i e n c e b u t t h a t a r e n o t n e c e s -s a r i l y p a r t o f t h e v e r i d i c a l r e p r e s e n t a t i o n o f p e r c e p t u a l e x p e -r i e n c e . " I f t h i s i n t e r p r e t a t i o n i s c o rr e c t , t h e n t h e r e s h o u l d b ei m p l i c a t i o n s f o r m e m o r y . S p e c i f i c a l l y , a s h i f t f r o m o n e m o o ds t at e t o a n o t h e r - - s a y , f r o m h a p p i n e s s t o s a d n e s s - - s h o u l dl e a d t o a l a r g e r l o s s o f m e m o r y f o r e v e n t s t h a t h a d b e e ni n t e r n a ll y p r o d u c e d r a t h e r t h a n e x t e r n a ll y p r e se n t e d .

W h a t e v i d e n ce i s t h e r e t o s u p p o r t t h e i d e a t h a t i n t e r n a le v e n t s a r e p a r t i c u l a r l y a p t t o b e f o r g o t t e n f o l l o w i n g a s h i f t inm o o d s t at e ? A t p r e se n t , t h e a n s w e r i s - - n o t m u c h . A b o u t a l lt h a t o n e c a n p o i n t t o a r e a f ew , s c a t te r e d r e p o r t s o f m o o dd e p e n d e n t m e m o r y i n s i t u a t io n s i n v o l v i n g t h e r e c a ll o f s ub -j e c t - p r o d u c e d a s s o c i a ti o n s t o w o r d s - - a t y p e o f i n t e r n a l l y g e n -e r a t e d e v e n t ( s e e E i c h , 1 9 8 0; W e i n g a r t n e r , 1 9 78 ) . W e i n g a r t -n e r , M i l l e r , a n d M u r p h y ( 1 9 7 7 ) , f o r e x a m p l e , f o u n d t h a ta f f e c t iv e l y d i s t u r b e d p a t i e n t s w h o h a d g e n e r a t e d v e r b a l a s s o -c i a t i o n s d u r i n g a n e p i s o d e o f m a n i a r e c a l l e d 9 7 % m o r e o ft h e i r a s s o c i a t i o n s w h e n t e s t e d i n a m a n i c t h a n i n a n o r m a lm o o d s t at e . S i m i l a r r e su l ts w e re o b t a i n e d b y G o o d w i n , P o w -e l l , B r e m e r , H o i n e , a n d S t e r n ( 1 9 6 9 ) i n a s t u d y i n v o l v i n ga l c o h o l - - a d r u g t h a t p r o d u c e s r e l i a b l e , s o m e t i m e s r a d i c a l ,a l t e r a t io n s o f a f f e c t (P e r s s o n , S jo b e rg , & S v e n s s o n , 1 9 8 0 ). In

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4 4 4 E R I C E I C H A N D J A N E T M E T C A L F Et h e i r st u d y , in t o x i c a t e d m e d i c a l s t u d e n ts m a d e 8 3 % f e w e re r r o r s t h a n d i d s o b e r s u b j e c t s w h e n t e s t e d f o r th e r e c a l l o fa s s o c i a t i o n s t h a t h a d b e e n g e n e r a t e d u n d e r t h e i n f l u e n c e o fa l c o h o l .

I n t e r e s t i n g l y , G o o d w i n a n d h i s c o l le a g u e s d e t e c t e d a s i g n i f -i c a n t , b u t m u c h l e ss s t r i k i n g , s t a t e d e p e n d e n t e f f e ct o f a l c o h o li n t h e p e r f o r m a n c e o f b o t h a v i s u a l - d i s c r i m i n a t i o n a n d as e n t e n c e - r e c a l l t a s k , a n d t h e y s a w n o s i g n o f s t a t e d e p e n d e n c ei n r e c o g n i t i o n m e m o r y f o r p i c tu r e s . T h e f a c t t h a t a ll t h r e e o ft h e s e t a s k s i n v o l v e d m e m o r y f o r e x p e r i m e n t e r - p r e s e n t e dr a t h e r th a n s u b j e c t - p r o d u c e d i t em s p r o m p t e d G o o d w i n e t a l.( 1 9 6 9, p . 1 3 5 9) t o s u g g e st t h a t " t h e w o r d - a s s o c i a t i o n t a s k ,m e a s u r i n g s i n g l e - tr i a l , ' s e l f - g e n e r a t e d ' l e a r n i n g , m a y b e p a r -t i c u l a r l y u s e f u l i n s t u d y i n g d i s s o c i a t i o n [ a / k / a s t a t e d e p e n d -e n c e ] . " T h o u g h t h i s su g g e s t i o n m a k e s s e n se , i t i s o p e n t o t w os e r i o u s o b j e c t i o n s .

F i r s t , t h e a s s o c i a t i o n t a s k a d m i n i s t e r e d b y G o o d w i n a n dh i s a ss o c i a t e s d i f f e r e d f r o m t h e i r o t h e r t a s k s n o t o n l y w i t hr e s p e c t t o t h e s o u r c e o f t h e t a r g e t i t e m s ( i .e . , i n t e r n a l v s.e x t e r n a l ) , b u t a l s o i n t e r m s o f t h e n a t u r e o f t h e i t e m s t h e m -s e l v es ( e .g . , w o r d s v s. p i c t u r e s ) a n d t h e m e t h o d b y w h i c hm e m o r y w a s t e s t e d ( e. g ., r e c a ll v s. r e c o g n i t i o n ) . T h e p r e s e n c eo f t h e se c o n f o u n d s m a k e s G o o d w i n e t a l . 's d a t a m o o t o n t h ei s s u e o f w h e t h e r i n t e r n a l e v e n t s a r e e s p e c i a l l y s u s c e p t i b l e t os t a t e d e p e n d e n c e .

S e c o n d , i t is p o s si b l e t h a t w h a t G o o d w i n a n d h i s c o ll a b o -r a t o r s d e m o n s t r a t e d w a s n o t a s t a t e d e p e n d e n t e f f e c t o f a l c o -h o l o n w o r d a s s o c i a t i o n r e c al l , b u t r a t h e r a s t a t e - c o n g r u e n te f fe c t . T h e d i s t i n c t i o n h e r e p a r a l l e l s t h a t b e t w e e n m o o d d e -pendence , w h i c h i m p l i e s t h a t e v e n t s e n c o d e d i n a p a r t i c u l a rm o o d a r e m o s t r e t r ie v a b l e i n t h a t m o o d , i r r e sp e c t iv e o f t h ee v e n t s ' a f f e c t i v e v a l e n c e o r c o n t e n t , a n d mood congruence,w h i c h i n v o l v e s t h e e n h a n c e d e n c o d i n g o r r e t r i e v al o f e v e n tsw h o s e a f f ec t iv e c o n t e n t i s c o n g r u e n t w i t h o n e ' s c u r r e n t m o o d( s ee B l a n e y , 1 9 8 6; B o w e r , 1 9 8 1) . T h o u g h m o o d d e p e n d e n c ea n d m o o d c o n g r u e n c e r e p r e s e n t t h e o r e t ic a l l y d i s t i n ct p h e -n o m e n a , s e v e r a l s t u d i e s h a v e y i e l d e d r e s u l t s t h a t c a n b ev i e w e d a s s u p p o r t f o r e i t h e r. O n e s u c h s t u d y i s t h a t o f W e i n -g a r t n e r e t a l. ( 19 7 7) , a n d a n o t h e r m a y b e t h a t o f G o o d w i n e ta l . ( 1 9 6 9 ) . R e g a r d i n g t h e f o r m e r s t u d y , B l a n e y ( 1 9 8 6 ) h a sr e m a r k e d t h at

Weingartne r e t a l . ' s (1977) resu l ts -- in d ica t ing tha t sub jec ts ex-periencing s trong m ood shifts were better able to regenerateassociations first generated in sam e as opposed to d ifferentm ood --c ou l d be seen as re f lec ting e i the r mood congruence o r[mood] s ta te dependence. Tha t is, the enhanced ab i l i tyof subjectsto recall what they had ge nerated when last in a given mo od was(a) because w hat was congruent with the mo od at firs t exposurewas s till congru ent with it a t su bsequent exposure, o r (b) becausere tu rn to tha t m ood he lped remind sub jec ts o f the mate r ia l theywere thinking of when last in that m ood, irrespective of content.(p. 237)

T h e s a m e a m b i g u i t y ar i se s i n c o n n e c t i o n w i t h G o o d w i n e ta l . ' s ( 1 9 6 9 ) r e s u l ts , i n a s m u c h a s t h e a s s o c i a t i o n s t h a t p e o p l ep r o d u c e w h i l e i n e b r i a t e d m a y b e q u a l i t a t i v e ly di f f e re n t f r o mt h o s e e l i c i t e d w h i l e s o b e r .

T o o v e r c o m e b o t h o f th e o b j e c t i o n s r ai s e d a bo v e , a n dt h e r e b y d e t e r m i n e m o r e d i r e c t l y w h e t h e r m o o d d e p e n d e n te f fe c ts ar e i n d e e d m o r e p r o n o u n c e d f o r in t e r n a l t h a n f o re x t e r n a l e v e n t s , t h e p r e s e n t r e s e a r c h r e l i e s o n p r o c e d u r e s

s i m i l a r t o t h o s e d e v e l o p e d b y S l a m e c k a a n d h i s a s s o c i a t e s( e .g ., S l a m e c k a & F e v r e i s k i , 1 9 8 3; S l a m e c k a & G r a f , 1 9 78 ) .I n o u r i n i t i a l s t u d y , s u b j e c t s e i t h e r r e a d a t a r g e t i t e m , s u c h a sGOLD, t h a t i s p a i r e d w i t h a c a t e g o r y n a m e a n d a r e l a t e de x e m p l a r ( e . g. , precio us meta ls: s i lver-GOLD), o r t h e y g e n e r a t e( w i t h a v e r y h i g h p r o b a b i l it y ) t h e s a m e i t e m w h e n p r i m e dw i t h i t s i n i t i a l l e t t e r , i n c o m b i n a t i o n w i t h t h e c a t e g o r y n a m ea n d e x e m p l a r c u e s ( e. g ., prec ious me ta l s : s i l ver - G) . I n t h i sm a n n e r , m e m o r y f o r o n e a n d t h e s am e t a r g e t i t e m c a n b ea s s e ss e d i n r e l a t i o n t o i t s s o u r ce : e i t h e r i n t e r n a l ( t h e g e n e r a t ec o n d i t i o n ) o r e x t e r n a l ( t h e r e a d c o n d i t i o n ) .

D u r i n g t h e e n c o d i n g s e s s i o n o f t h e f i r s t s t u d y , s u b j e c t sg e n e r a t e 1 6 t a r g e t i t e m s a n d r e a d 1 6 o t h e r s w h i l e t h e y a r ee i t h e r h a p p y o r s a d - - m o o d s e n g e n d e r e d b y m e a n s o f a " c o n -t i n u o u s m u s i c t e c h n i q u e , " e x p l~ / in e d b e l o w . D u r i n g t h e r e -t r i e v a l s e s s io n , h e ld 2 d a y s l a t e r , s u b je c t s r e c e iv e a s u rp r i s et e s t o f f r e e r ec a l l o f t h e 3 2 t a r g e t i t e m s . T h e s u b j e c t s ' m o o da t r e t ri e v a l e i t h e r d o e s o r d o e s n o t m a t c h t h e m o o d t h e ye x p e r i e n c e d d u r i n g e n c o d i n g .

I f m e m o r y i s m o o d d e p e n d e n t , t h e n a s i g ni f i ca n t a d v a n t a g eo f m a t c h e d o v e r m i s m a t c h e d m o o d c o n d i t i o n s (e .g ., e n c o d eh a p p y / r e t r i e v e h a p p y v s . e n c o d e h a p p y / r e t r i e v e s a d ) s h o u l db e e v i d e n t i n p e r f o r m a n c e o f t h e r e c a l l t e s t. W h e t h e r t h i sa d v a n t a g e i s g r e a t e r f o r i t e m s t h a t h a d b e e n g e n e r a t e d , r a t h e rt h a n r e a d , i s t h e f i r st a n d f o r e m o s t i s s u e o f i n t e r e s t i n t h i sr e s e a rc h .

F o l l o w i n g t h e t e s t o f i t e m r e c a l l , s u b j e c ts a r e p r e s e n t e d w i t ha l i s t o f a l l 3 2 p r e v i o u s l y e n c o d e d t a r g e ts , i n t e r s p e r s e d w i t h3 2 n e w i t e m s . T h e s u b j e c t s a r e a s k e d t o r e s p o n d " o l d " t o a n yi t e m t h e y r e c o g n i z e a s h a v i n g g e n e r a t e d o r r e a d d u r i n g t h ee n c o d i n g s e s s i o n a n d t o r e s p o n d " n e w " o t h e r w i s e . G i v e n t h a tm o o d d e p e n d e n t e f f ec t s r a r e l y e m e r g e w h e n t h e r e t r i e v a l o fex te rna l e v e n t s i s p r o m p t e d w i t h e x p li c i t r e m i n d e r s - - s u c h a st h e " c o p y c u e s " t h a t a r e a v a i l a b l e i n a t e s t o f r e c o g n i t i o nm e m o r y ( s ee B ow e r , 1 9 8 1; E ic h , 1 9 8 0 ) - - o n e w o u l d n o t e x -p e c t t o f i n d a r e li a b l e a d v a n t a g e o f m a t c h e d o v e r m i s m a t c h e dm o o d c o n d i t i o n s i n t h e p r o b a b i l i t y w i t h w h i c h r e a d i t e m s a r ec o r r e c t l y cl a s s if i e d a s o ld . W h e t h e r s u c h a n a d v a n t a g e a c c r u e st o t h e p r o m p t e d r e t ri e v a l o f internal e v e n t s - - o r , m o r e s p ec i f-i c al l y, t o t h e r e c o g n i t io n o f g en e r a t e d i t e m s m i s t h e s e c o n di s s u e a t s t a k e in th i s s tu d y .

F o l l o w i n g t h e t e s t o f i t e m r e c o g n i t i o n , s u b j e c t s a r e a g a i np r e s e n t e d w i t h a l l o f t h e i t e m s t h e y h a d i d e n t i f i e d as o l d a n da r e a s k e d t o s p e c i f y w h e t h e r t h e y h a d g e n e r a t e d o r r e a d t h e s ei t e m s d u r i n g t h e e n c o d i n g s e s s i o n . T h e i n t e n t h e r e i s t oin v e s t ig a t e a t h i rd i s s u e w h ic h , c a s t a s a q u e s t io n , i s : E v e n i fa s h i f t i n m o o d s t a t e d o e s n o t i m p a i r t h e s u b j e c t s ' a b i l i t y t or e c o g n i z e t h e occurrence o f a p a r t i c u l a r p a s t e v e n t , d o e s s u c ha s h i f t a d v e r s e l y a f f e c t t h e i r r e c o g n i t i o n o f t h e s o u r c e o r origino f t h a t e v e n t ?

T h e f o u r t h a n d f i n a l i ss u e o f c u r r e n t i n t e r e s t c o n c e r n s t h er o l e o f a r o u s a l i n m o o d d e p e n d e n t m e m o r y . D r a w i n g o n t h e i ro w n a n d o t h e r ' s d a t a , C l a r k , M i l b e r g , a n d R o s s ( 1 9 8 3 ) h a v ea r g u e d t h a t ( a ) a r o u s a l c a n a c t a s a c u e f o r th e r e t r i e v a l o fa r o u s a l - re l a t e d m a t e r i a l f r o m m e m o r y ( s o t h a t e v e n t s e x p e r i-e n c e d s h o r t l y a f t e r , s a y , a s e s s i o n o f s t r e n u o u s e x e r c i s e a r eb e t t e r r e m e m b e r e d i n a p h y s i c a l l y a c t i v e t h a n i n a p h y s i c a l l yr e l a x e d st a t e) , a n d ( b ) i n t h e m a i n , p o s i t i v e m o o d s , s u c h a sh a p p i n e s s , a r e a c c o m p a n i e d b y h i g h e r l e v e l s o f a r o u s a l t h a n


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M O O D D E P E N D E N T M E M O R Y 44 5a r e n e g a ti v e m o o d s , s u c h a s s a d n es s . T h u s , a c c o r d i n g t o C l a r ka n d h e r c o l l e a g u e s , m e m o r y i m p a i r m e n t s i n c u r r e d i n t h et r a n s i t i o n f r o m h a p p i n e s s t o s a d n e s s ( o r v i c e v e r s a ) m a y b et h e r e s u l t o f a c h a n g e i n a r o u s a l , r a t h e r t h a n a c h a n g e i nm o o d . T o c h e c k t h i s p o s s i b i li t y , w e a s k s u b j e c t s t o r a t e t h e i rc u r r e n t l e ve l s o f b o t h m o o d a n d a r o u s a l o n s e v e r a l o c c a s i o n so v e r t h e c o u r s e o f t h e e n c o d i n g a n d r e t r i e v a l s e s si o n s . T h e s er a t i n g s a r e t h e n u s e d t o s e p a r a t e t h e s u b j e c t s i n t o g r o u p s ; f o ri n s t a n c e , s u b j e c t s w h o s h o w a s u b s t a n t i a l s h i ft b e t w e e n s e s-s i o n s i n m o o d a s we l l a s a r o u s a l , a s o p p o s e d t o s u b j e c t s w h oe x p e r i e n c e a la r ge c h a n g e i n m o o d b u t o n l y a s m a l l c h a n g ei n a r o u sa l . B y d e t e r m i n i n g t h e d e g r e e t o w h i c h t h e s e g r o u p sd i f f e r w i t h r e s p e c t t o i t e m r e c a l l , s o u r c e r e c o g n i t i o n , a n d o t h e rm e m o r y m e a s u r e s , w e e n d e a v o r t o e v a l u a t e C l a r k e t a l .' s( 1 9 8 3 ) c l a i m t h a t m o o d d e p e n d e n t e f f e ct s m a y b e m e d i a t e db y a l t e r a t i o n s i n l e v e l o f a r o u s a l .

E x p e r i m e n t 1Method

Subjects and design. The exper iment employed 48 Univers i ty ofBr i t i sh Columbia (UBC) undergraduates as subjects (each of whomreceived course credi t in re tur n for the i r par t ic ipat ion) and enta i led a2 x 2 x 2 mixed design. One betw een-sub jects factor was the mo od(happy or sad) in which target i tems were encoded, an d a second wasthe mood (again , happy or sad) in which re t r ieval of the i tems wastes ted. The cross ing of these two factors def ined four encoding/ 're t r ieval condi t ions , each of which was represented by 12 randomlyassigned subjects. The third factor, i tem type, was varied withinsubjects.

Par t ic ipants were tes ted individual ly throughout the course of theexperim ent, whic h was divided into two sessions. We will refer to thefirst of these as the encoding session and to the second as the retrievalsession; the intersession interval was 2 days. Details on the materialsand proced ures used in each sess ion are summariz ed in the fol lowingsections.

Encod ing session. At the start of this session, subjects were toldthat the present exper iment was par t of a research program aimed a tunders tanding how moods af fec t the performance of word associa-t ion, speech product ion, and other cogni t ive tasks , and how theperformance of such tasks in turn af fec ts mood. I t was expla ined thatthe exper iment would be divided in to two sess ions , spaced 2 daysapar t , and that each sess ion would en ta i l a d i f ferent se t of tasks. Thesubjects were then provided w i th a copy of the matr ix drawn in Figure1-- an adapta t ion of the "af fect gr id" des igned by Russel l, Weiss, andMende lsohn ( in press) - - toge ther wi th these ins t ruct ions :

We will use the matrix to measure your feelings at a particularmom ent , Two types of fee lings are of in terest : one i s your levelof af fect or mo od -- t ha t i s , how happy or sad you fee l - -and theother i s your level of arousal . The center of the matr ix representsneut ra l fee l ings : you are nei ther happy nor sad, and you arenei ther aroused nor unaroused. As you move f rom the centercolumn to the r ight , your mood changes for the bet ter - - f romfeeling s l ight ly happy to moderate ly hap py to very happy andf inally to ext remely ha pp y-- and as you move f rom the centercolumn to the lef t , your mood changes for the worse-- f romfeeling slightly sad to mo derate ly sad to very sad to e xtremelysad. In a s imi lar manne r , as you move upwards f rom the centerrow, your level of arousal be comes progressively higher, and asyou mo ve downwards f rom the center row, your level of arousalbeco mes progressively lower. Thus, fo r example, if you n ow feelmoderate ly sad and moderate ly aroused, you should mark the

Figure 1. The matr ix on which subjects p laced a s ingle mark toindicate thei r current levels of mood (hor izonta l axis) and arousal(vertical axis). (Adapted from "The Affect Grid: A New Single-ItemScale of Pleasure and Arousal" by J, A. Russell , W. Weiss, and G. A.Mendelsohn, in press, Journal o f Personality and Soc ial Psychology.Copyr ight by the American Psychological Associa t ion. Adapted bypermission.)

square located three rows down f rom the th i rd column on theleft . Alternatively, if you are experiencing an average level ofarousal, and feel slightly happy, you should place a check markjus t to the r ight of the center square . With these examples inmind, p lease mark the on e square tha t bes t reflects your currentfeelings."A f t e r m a k i n g t h e i r m a r k , t h e s u b j e c ts w e re i n f o r m e d o f th e

fo l l ow ing :In toda y's session you will l isten to a selection of classical musicthat should help you develop a happy (sad) mood. However ,music a lone canno t create the des i red af fec t, so you should t ryto th ink of something that makes you happy (sad). You m ayfind it especially helpful to concentrate on happy (sad) eventsthat you have personal ly exper ienced.Whe n I th ink that you have developed an appropr ia te mood,we will begin today's main task, which will go like this. I willread to you the name of a category, such as ice cream flavors,and an i tem that f i ts tha t ca tegory, such as chocolate. I will thenask you to genera te another i tem that belongs to the samecategory and that s tar t s w i th a cer ta in le t ter of the a lphabet . Forinstance, if I said ice cream flavors: chocolate-V , you m igh t t h inko f VANILLA.Whatev er i t i s tha t you do th in k of , you should sayi t out loud, so that I can keep t rack of the i tems you genera te .Whi le I w i ll somet imes ask you to genera te an i tem that beginswith a partic ular letter, as in the V-VANILLA case jus t m ent ioned,I will occasionally read to you the complete second item, whichyou should then read back to me a loud. For example , i f I sa idnatur al earth form atio ns: river-vaLLEY, you should respond bysaying VALLEr out loud. These read-only i tems are included sothat you wi ll remain a ler t throug hout the course of the task , andso that you wi ll not know in advance whethe r you mu st genera teor read the second i tem aloud. "

O n r e c e i v i n g th e s e i n s t r u c t i o n s , t h e s u b j e c t s w e r e s e a t e d i na s p e c i a l l y d e s i g n e d l o u n g e c h a i r ( a S e n s o r y E n v i r o n m e n tE n g i n e e r s A l p h a C h a m b e r ) t h a t c o n t a i n e d r e c e s s e d s t e r e os p e a k e r s . T h r o u g h t h e s e s p e a k e r s w as p l a y e d , a t a c o m f o r t a b l el i s te n i n g v o lu m e , o n e o f t w o s e l ec t io n s o f " h a p p y " m u s i c ( as e g m e n t o f E i n e K l e i n e N a c h t m u s i k [5 min: 10 s] or Diver t i -m e n t o # 1 3 6 [ 4 : 10 ] , b o t h b y M o z a r t ) , o r o n e o f t w o s e l e c t i o n s


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4 4 6 E R I C E I C H A N D J A N E T M E T C A LF Eo f " s a d " m u s i c ( A l b i n o n i ' s A d a g i o i n G M i n o r [ 6 : 32 ] o rB a r b e r ' s Adagio pour Cordes [ 5 : 33 ] ) . The t w o s e l e c t i ons r e p -r e s e n t in g e a c h t y p e o f m u s i c w e r e a s s i g n ed a t r a n d o m , e x c e p tt h a t s u b j e c t s w h o c o m p l e t e d b o t h t h e e n c o d i n g a n d t h e r e -t r i e v a l s e s s i o n i n t h e s a m e m o o d ( h a p p y o r s a d ) w e r e p l a y e do n e s e l e c t io n o f t h e a p p r o p r i a t e m u s i c d u r i n g e n c o d i n g a n dt he a l t e r na t i ve s e l e c t i on du r i ng r e t r i e va l . Eve r y s e l e c t i on ha dbe e n r e pe a t e d l y r e c o r de d on a 45 - r a i n c a s s e t t e t a pe ; t h i s s a ve du s t h e t r o u b l e o f h a v i n g t o s t o p a n d r e w i n d t h e t a p e , w h i c hm i g h t h a v e im p e d e d d e v e l o p m e n t o f t h e m o o d w e w e r eseek ing to inst il l.

F i v e m i n u t e s f o l l o w i n g m u s i c o n s e t , a n d e v e r y 5 m i nt h e r ea f te r , t h e s u b j ec t s r a t e d t h e i r c u r r e n t l e v e ls o f m o o d a n da r o u s a l o n a n e w m a t r i x . T h e m u s i c p l a y e d o n w h i l e t h es ub j e c t s m a de t he s e r a t i ngs ; i nde e d , t he m us i c , onc e s t a r t e d ,d i d n o t s t o p u n t i l t h e s u b j e c t s w e r e d i s m i s s e d a t t h e e n d o ft he s e s s i on ( he nc e t he t e r m cont inuous m u s i c t e c h n i q u e ).

T o b e g i n t h e t a sk o f g e n e r a t i n g a n d r e a d i n g i te m s , t h es u b j e c t s w e r e r e q u i r e d , a t a m i n i m u m , t o r a t e t h e m s e l v e s a sb e i n g e i t h e r v e r y h a p p y o r v e r y s a d . T h i s w a s a s t r i n g e n tc r i t e r i on , a nd a s w i l l be s how n s ho r t l y , t he s ub j e c t s t ookc o n s i d e r a b l e t i m e t o a t t a in t h e c r i ti c a l le v e l o f m o o d . N e v e r -t h el e ss , w e t h o u g h t t h a t b y i m p o s i n g t h i s c r it e r io n , t h e o d d so f d e m o n s t ra t in g m o o d d e p e n d e nt m e m o r y w o u ld b e i m -p r o v e d .T w o a d d i ti o n a l p o i n t s c o n c e r n i n g t h e m o o d c r i t e r io n m e r i tc o m m e n t . F i r s t , t h e s u b j e c t s w e r e n o t t o l d t h a t t h e s t a r t o ft h e g e n e r a t e / r e a d t a s k w a s c o n t i n g e n t o n t h e i r a c h i e v i n g ac e r t a in l e v e l o f h a p p i n e s s o r s a d n e s s. T h i s c o n t i n g e n c y w a sk e p t c o n f i d e n t i a l b e c a u s e w e d i d n o t w a n t t h e s u b j e ct s t o t ryt o r u s h m a t t e r s b y r a t i n g t h e i r c u r r e n t m o o d a s b e i n g m o r ee x t r e m e t ha n i t a c t ua l l y w a s . Se c ond , b e c a us e t he s pe c i f i c a i mo f t h e c o n t i n u o u s m u s i c t e c h n i q u e w a s t o a lt e r th e s u b j e c t s 'l e ve l o f m o o d , r a t h e r t h a n t h e i r l e ve l o f a ro u s a l , r a t i n g s o f t h el a tt e r p la y e d n o p a r t i n d e t e r m i n i n g w h e t h e r o r w h e n t h es u b j ec t s w e r e r e a d y t o b e g i n t h e g e n e r a t e / r e a d t a sk . T h u s , f o re x a m p l e , a s u b j e c t w h o h a d b e e n l i s t e n i n g t o h a p p y m u s i c ,a n d t h i n k i n g h a p p y t h o u g h t s , w a s c o n s i d e r e d " r e a d y " o n c eh e o r s h e p la c e d a c h e c k m a r k i n a n y o f th e s q u a r e s i n c l u d e di n e i th e r o f th e t w o r i g h t- m o s t c o l u m n s o f th e m o o d / a r o u s a lm a t r i x ( s e e F i gu r e 1 ). R a t i ngs o f a r ous a l , t he r e f o r e , w e r ef r e e - - n o t f o r c e d - - t o c o v a r y w i th t h o s e o f m o o d .

O n r e a c h i n g t h e r e q u i s it e l e v e l o f m o o d , t h e s u b j e c t s w e rea ud i t o r i l y p r e s e n t e d w i t h a l i st c om po s e d o f 32 t ri a ds , a r -r a n g e d i n a r a n d o m o r d e r . O f t h e s e 3 2 t ri a d s, 1 6 w e r e o f t h ef o r m c a t e g o r y n a m e : c a t e g o r y e x e m p l a r - t a r g e t i t e m t o b e r e a d(e.g., precious metals: silver-GOLD), a n d 1 6 w e r e o f t h e f o r mc a t e g o r y n a m e : c a t e g o r y e x e m p l a r - i n i t ia l l e tt e r o f ta r g e t i t e mt o be ge ne r a t e d ( e .g ., mus ica l ins trument s : drum-G ) . A s n o t e de a r l i e r , t he s ub j e c t s w e r e a s ke d t o s t a t e a l oud bo t h t he ge ne r -a t e d a nd t he r e a d i t e m s ( t o c on t r o l f o r ove r t a c t i v i t y ) , a ndt h e i r s t a te m e n t s w e r e tr a n s c r i b e d b y t h e e x p e r i m e n t e r ( t om o n i t o r r e s p o n s e a c c u r a c y ). T h e r a t e o f i t e m p r e s e n t a t i o nw a s s u b j e c t - p a c e d , a n d t h e t o t a l t i m e t a k e n w a s r e c o r d e d b yt h e e x p e r i m e n t e r .F o u r l i st s w e r e p r e p a r e d f o r p u r p o s e s o f t h e g e n e r a t e / r e a dt a s k . The s e l i s t s w e r e s t r uc t u r e d i n s uc h a w a y t ha t ( a ) a l l o ft he m a t e r i a l s ( i. e. , c a t e go r y na m e s , c a t e g o r y e xe m pl a r s , a n dt a r ge t i te m s ) i n c l ude d i n o ne p a i r o f l is t s w e r e d i f f e r e n t f r om

t hos e i nc l ude d i n t he o t he r pa i r , a nd ( b ) w i t h i n e i t he r pa i r ,a n y i t e m t h a t w a s t o b e g e n e r a t e d i n o n e l i s t w a s t o b e r e a di n t h e o t h e r . E v e r y s u b j e c t w a s p r e s e n t e d w i t h o n e o f th e f o u rl i s t s ; t o gua r d a ga i ns t i t e m - s e l e c t i on a r t i f a c t s , t he a s s i gnm e n to f li st s to s u b j e c t s w a s c o u n t e r b a l a n c e d a c r o s s e n c o d i n g /r e t r i e va l c ond i t i ons .

O n c o m p l e t i n g t h e g e n e r a t e / r e a d t a s k, a ll s u b j ec t s m a r k e da n e w m o o d / a r o u s a l m a t r i x . T h o s e w h o h a d b e e n l i s t e n i n gt o h a p p y m u s i c w e r e t h e n d i s c h a r g e d , w i t h a r e m i n d e r t or e t u r n i n 2 d a y s t o c o m p l e t e a n u m b e r o f n e w a n d d i f f e re n tt a sk s ; t h e y w e r e n o t i n f o r m e d t h a t t h e i r m e m o r y f o r t h e it e m st h e y h a d g e n e r a t e d o r r e a d t h i s d a y w o u l d b e t e s t e d a t t h a tt i m e . S u b j e c t s w h o h a d b e e n l i s t e n i n g t o s a d m u s i c s t a y e dl o n g e r - - s n a c k i n g o n c o o k i e s a n d c h a t t i n g w i t h t h e e x p e r i -m e n t e r w h i l e h a p p y m u s i c p l a y e d i n t h e b a c k g r o u n d - - t oe ns u r e t ha t t he i r m ood w a s a t l e a s t ne u t r a l be f o r e t he y l e f tt h e l a b o r a t o r y .Retrieval session. P r o c e d u r e s i n v o l v e d i n m a n i p u l a t i n ga n d m e a s u r i n g m o o d d u r i n g t h e r e t r i e v a l s e s s i o n w e r e i d e n -t ic a l t o th o s e e m p l o y e d d u r i n g t h e e n c o d i n g s e ss io n .W h e n s u b j ec t s a tt a i n e d t h e a p p r o p r i a t e l ev e l o f m o o d( e i t he r ve r y ha pp y o r v e r y s a d , ir r e s pe c t i ve o f c u r r e n t l e ve l o fa r ous a l ) , t he y w e r e a s ke d t o r e c a l l t he i t e m s t ha t t he y ha de i t he r ge ne r a t e d o r r e a d 2 da ys e a r l i e r . The s ub j e c t s r e c a l l e dt h e i te m s a l o u d , i n a n y o r d e r , a n d w i t h o u t b e n e f i t o f a n ys p e c if ic r e m i n d e r s o r c u e s w i t h i n a 5 - m i n p e r i o d .

Fo l l ow i ng i te m r e c a ll , t he s ub j e c t s a ga i n r a t e d t he i r c u r r e n tl e ve l s o f m o o d a n d a r o u s a l. S u b j e c ts w e r e t h e n p r e s e n t e d w i t ha li s t c on t a i n i n g a l l 32 t a r ge t it e m s f r o m t he e n c od i ng s e s s ion ,r a n d o m l y i n t e r s p e r s e d w i t h 3 2 p r e v i o u s l y u n e n c o d e d i t e m s .P r e s e n t a t i o n w a s a u d i t o r y a n d s u b j e c t - p a c e d . T h e s u b j e c t sw e r e i n s tr u c t e d t o r e s p o n d a l o u d b y s a y i n g " o l d " t o a n y i t e mt h e y r e m e m b e r e d h a v i n g g e n e ra t e d or r e a d 2 d a y s b e f o r e a n db y s a y i n g " n e w " o t h e r w i s e .

T h e t e st o f i t e m r e c o g n i t i o n w a s f o ll o w e d b y o n e o f s o u r c er e c ogn i t i on . Fo r t h i s pu r pos e , t he s ub j e c t s w e r e a ga i n p r e -s e n t e d a u d i to r i ly , a n d a t t h e i r o w n p a c e , w i t h e v e r y it e m t h e yh a d i d e n t i fi e d a s " o l d " m o m e n t s b e f o r e , a n d t h e y w e r e a s k e dt o s p e c if y a l o u d w h e t h e r t h e y h a d e i t h e r g e n e r a t e d o r r e a de a c h o f t he s e i t e m s 2 da y s e a r li e r.

S u b s e q u e n t t o s o u r c e r e c o g n it i o n , su b j e c ts m a r k e d a n o t h e rm o o d / a r o u s a l m a t r i x a n d w e r e t h e n d e b r ie f e d . A s w a s th ec a s e a t e nc od i ng , s ub j e c t s w ho c om pl e t e d t he r e t r i e va l s e s s i onw h i le s a d w e r e n o t d i s m i s s ed u n t i l t h e ir l e v e l o f m o o d w a sno t l e s s t ha n ne u t r a l .R e s u l t s

Mood and arousa l ra t ings . M e a n r a ti n g s o f m o o d r e-c o r d e d o n s e v e n s e le c te d o c c a s i o n s o v e r t h e c o u r s e o f t h ee x p e r i m e n t a p p e a r i n T a b l e 1 . T h e s e r a t i n g s w e r e d e r i v e d b yt r a n s l a t i n g t h e m a r k s m a d e b y s u b j e c t s a l o n g t h e h o r i z o n t a la x is o f t h e m o o d / a r o u s a l m a t r i x i n t o a n i n t e g e r s c o r e r a n g i n gf r o m - 4 (ex t r eme ly sad) t h r o u g h 0 (neutral) to 4 (ex t r eme lyhappy).T h r e e a s p e c t s o f t h e d a t a d e s e r v e c o m m e n t . F i rs t, a s w o u l db e e x p e c t e d , r a t in g s o f m o o d r e g is t er e d a t t h e b e g i n n i n g o fe i t he r t he e nc od i ng o r t he r e t r i e va l s e s s i on ( r a t i ngs ESB a ndR S B ) w e r e a b o u t t h e s a m e , r e g a r d le s s o f w h e t h e r s u b j e c ts


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Table 1M o o d a s a F u n c ti o n o f R a t i n g O c c a s io n a n dEncoding~Re tr ieva l Condi t ionEncoding/retrievalcondition

Rating occasionn ESB BET AET RSB BRc ARc ARn

Experiment 1Happy/happy 12 0.7 3.1 2.4 0.9 3,0 2.3 1.8Happy/sad 12 0.3 3.1 1.9 0.8 - 3 . 0 - 1 . 8 - 1 . 5Sad/happy 12 0.5 - 3 . 0 - 1 . 3 0.7 3.0 1.8 1.6Sad/sad 12 1.1 -3 .0 -1 .2 0.9 -3 .0 -1 .3 -0 .8

Experiment 2Happy/happy 24 0.8 3.0 2.4 1.3 3.1 1.9 1.8Happy/sad 24 1.1 3.1 2.1 0.9 -3.1 -1 .9 -1 .3

Experiment 3Happy/happy 24 1.4 3.0 1.6 0,8 3.0 1.7 1.4Happy/sad 24 1.0 3.0 1.5 0.8 - 3 . 0 - 1 . 5 - 0 . 3

Experiment 4Happy/happy 48 1.0 3.1 2.0 l. l 3.0 2.1 1.7Happy/sad 48 1.0 3.0 2.0 1.0 -3 .0 -1 .8 -1 .2

Note. Ratings derive from a 9-point scale ranging from 4 (extremelyhappy) through 0 (neutral) to -4 (extremely sad). n = number ofsubjects per mean rating. ESB = encoding session baseline; BET =before encoding task; AET = after encoding task; RSB = retrievalsession baseline; BRc = before recall task; ARc = after recall task andbefore recognition tasks; ARn = after recognition tasks.

tasks. This is an im porta nt point, an d we will return to it inthe final discussion.

Regarding the time required to reach the critical level ofmood, a 2 x 2 (Happy/Sad Mood x Encoding/RetrievalSession) analysis showed that subjects took significant ly ongerto becom e very sad than to be come very happy (18.7 vs. 15.1min), F(1, 92) = 5.18, M S e -- 58.13, p < .05. Thi s may reflectthe fact that subjects generally felt good at the start of theencoding and retrieval sessions: Mean mood ratings recordedat assessments ESB (0.7) and RSB (0.8) were both reliablygreater tha n zero, ts(47) > 2.91, ps < .01. Neither the ma ineffect of experimental session nor the interactio n of sessionswith type of moo d had a significant influence on the timetake n to attain the requisite moo d level (Fs > 1).

Ratings of arousal are summariz ed in Table 2. These ratingswere assigned in accordance with marks made by subjectsalong the vertical axis of the moo d/arou sal matrix and variedfrom 4 ( ex t r eme ly h igh arousa l ) through 0 ( neu tra l ) to -4( ex t r em e ly low arousal ).

Comparis on of Tables 1 and 2 suggests that the co ntin uousmusic technique caused substantial changes not only in thesubjects' ratings of mood--which is what the technique wasspecifically designed to do -- bu t in their ratings of arousal aswell. More to the point, happy subjects rated themselves asbeing more aroused than did sad subjects, and this was truefor all ratings taken after the music had started (viz., ratingsBET, AET, BRc, ARC, and AR n in Table 2), ts(46) > 4.24,ps < .01.

were soon to start listening to happy or to sad music. Second,in keeping with the level-of-mood criterion stated earlier,subjects rated themselves as being, at a mi ni mu m, either veryhappy (3 or higher) or very sad (-3 or lower) just before theybegan the task of generating and reading words (rating BET),and again, just before they began the task of recalling thesewords (rating BRc). Third, the impact of the mood manipu-lation declined over time and across tasks. To clarify, inspec-tion of Table 1 reveals that the mean difference in moodratings made by encode-happy an d encode-sad subjects (ns =24) was 6.1 points at the beginn ing of the generate/read task(rating BET: happy = 3.1; sad = - 3.0) , bu t only 3.5 points atits finish (rating AET: happy = 2.2; sad = -1.3). Similarly,the mean difference in mood between retrieve-happy andretrieve-sad subjects (ns = 24) decreased from 6.0 pointsbefore the test of item recall (rating BRc: happy = 3.0, sad =-3.0) to 3.7 points after recall and before item recognition(rating ARc: happy = 2.1, sad = -1 .6 ) to 2.9 points after thefinal test of source recognit ion (rating ARn: h appy = 1.7, sad= -1.2) . These dim inish ing differences may reflect a regres-sion to the mea n, or they may be due to the encod ing andretrieval tasks themselves. Whatev er the reason, it should benoted that although the mood manipula tion lost some of itseffectiveness, it did not lose it all: Differences between ha ppyand sad subjects in their mean ratings of mood were signifi-cant at all posttask assessments (viz., ratings AET, ARc, andARn) , ts(46) > 9.51, ps < .01. Thus, it appears that once astate of happiness or sadness had been induced, it remainedrelatively, though n ot absolutely, stable over time and across

Table 2A r o u s a l a s a F u n c t i o n o f R a t i n g O c c a si o n a n dEncoding~Re tr ieva l Condi t ion

Encoding/retrievalcondition n ESBRating occasion

BET AET RSB BRc ARc ARnExperiment 1

Happy/happy 12 0.8 0.6 0.9 0.7 1.0 1.2 1.6Happy/sad 12 -0 .3 0.8 1.6 0.8 -0 .8 -0 .5 -0 .4Sad/happy 12 -0. 3 -1.8 - l . 0 -0. 3 1.6 1.6 1.8Sad/sad 12 0.3 -1. 8 -0. 4 0.3 -1. 9 -0. 4 0.2Experiment 2

Happy/happy 24 0.2 0.3 1.0 0.6 0.7 1.1 1.3Happy/sad 24 -0 .2 0.4 1.3 0.3 -1 .4 -1 .0 0.0Experiment 3

Happy/happy 24 0.1 0.2 0.7 1.0 0.7 1.3 1.5Happy/sad 24 0.0 0.3 1.2 0.5 -1 .7 -0 .2 0.4Experiment 4

Happy/happy 48 0.2 0.1 0.7 0.6 0.3 0.7 1.0Happy/sad 48 0.3 0.6 1.2 0.5 -1 .8 -0 .9 -0 .3Note. Ratings derive from a 9-point scale ranging from 4 (extremelyhigh arousal) through 0 (neutral) to -4 (extremely low arousal), n =number of subjects per mean rating. ESB = encoding session baseline;BET = before encoding task; AET -- after encoding task; RSB =retrieval session baseline; BRc = before recall task; ARc = after recalltask and before recognition tasks; ARn = after recognition tasks.


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448 E R I C E I C H A N D J A N E T M E T C A L F EA d d i t i o n a l e v i d e n c e o f c o v a r i a t i o n b e t w e e n r a t i n g s o f m o o d

a n d a r o u s a l w a s o b t a i n e d b y m e a n s o f c o r r e l a t i o n a l a n a ly s i s.F o r p u r p o s e s o f t h i s an a l y si s , w e c o m p u t e d t h e p r o d u c t -m o m e n t c o r r e l a ti o n b et w e e n t h e s e v en p a i r s o f m o o d a n da r o u s a l r a t i n g s (i .e . , r a t i n g s E S B t h o u g h A R n i n T a b l e s 1 a n d2 ) p r o v i d e d b y e v e r y s u b j e c t. O f t h e 4 8 i n d i v i d u a l - s u b j e c tc o r re l a t io n s , 2 5 w e re s ig n i f i c a n t ly p o s i t i v e , r s (5 ) > . 7 5 , a n do n l y 1 w a s s i g n i f i c a n t l y n e g a t i v e . T h e m e a n c o r r e l a t i o n w a s. 5 0 , w h ic h e x c e e d s z e ro b y a r e l i a b le m a rg in , t (4 7 ) - -- 6 . 8 0 , p< .01 .Item-generation errors and encoding-task time. T h e m e a nn u m b e r o f t im e s t h a t s u b j e ct s g e n e r a t ed a t a r g e t it e m o t h e rt h a n t h e o n e w e h a d i n t e n d e d w a s 1 . 0 0 u n d e r b o t h e n c o d e -h a p p y a n d e n c o d e - s a d c o n d i t io n s . T h u s , t h e o v e r a ll e r ro r r a t ei n t h e g e n e r a t i o n t a s k w a s a m o d e s t 6 . 3 % . I t e m s f o r w h i c hs u c h e r r o r s o c c u r r e d w e r e o m i t t e d f r o m t h e s c o r i n g o f t h ei t e m r e c a l l , i t e m r e c o g n i t i o n , a n d s o u r c e r e c o g n i t i o n d a t a .

B e c a u se p s y c h o m o t o r s l ow i n g is a s a l ie n t s y m p t o m o fd e p r e s s i o n , w h e t h e r n a t u r a l l y o c c u r r i n g o r e x p e r i m e n t a l l yi n d u c e d ( C l a r k , 1 9 8 3 ) , i t s e e m s r e a s o n a b l e t o s u p p o s e t h a ts u b j ec t s w o u l d t a k e l o n g e r t o c o m p l e t e t h e g e n e r a t e / r e a d t a s ki f t h e y w e r e s a d t h a n i f th e y w e r e h a p p y . T h i s w a s i n d e e d t h ec a s e: W h e r e a s s a d s u b j e c t s r e q u i r e d a n a v e r a g e o f 2 7 0 s t og e n e r a t e o r r e a d t h e 3 2 t a r g e t i te m s , h a p p y s u b j e c t s p e r f o r m e dt h e s a m e e n c o d i n g t a s k i n a n a v e r a g e o f 2 4 3 s , t ( 4 4 ) = 2 . 6 6 ,p < . 05 ; t a s k - p e r f o r m a n c e t i m e s w e r e n o t a v a i l a b l e f o r 2s u b je c t s .Item recall. T h e m e a n p r o b a b i l i t i e s w i t h w h i c h g e n e r a t e da n d r e a d i t e m s w e r e r e c a l l e d in e a c h e n c o d i n g / r e t r i e v a l c o n -d i t i o n a r e p r e s e n t e d in T a b l e 3 . A 2 2 2 m i x e d - d e s i g n

T a b l e 3Probability of Recall as a Function of Item Type andEncoding/Retrieval ConditionI tem typeEncoding /re t r ieva lc o n d i t io n n G /1 R / I G /3 R /3

Experiment 1Hap py/ha ppy 12 .32 .09Ha ppy /sad 12 .17 .04Sad /hap py 12 .17 .05Sad/ sad 12 .27 .06

Experiment 2Hap py/h appy 24 .22 .25Hap py/sad 24 .14 .23

E x p e r im e n t 3Hap py/h appy 24 .35 .19Hap py/sad 24 .29 . l 0

E x p e r im e n t 4Hap py/h appy 24 .11 .36Hap py/sad 24 .07 .29Hap py/ha ppy 24 .04 .25Happ y/sad 24 .03 .24

Note. n = num ber o f sub jec ts pe r mean probab i l i ty . G /I = oncegenera ted ; R/1 = once read ; G/3 = thrice generated; R/3 = thriceread.

a n a l y s i s o f t h e r e c a l l d a t a d i s c l o s e d ( a ) a m a i n e f f ec t o f i t e mt y p e , s o t h a t g e n e r a t e d i t e m s w e r e m o r e l i k e l y t o b e r e c a l l e dt h a n w e r e r e a d i t e m s , F ( 1 , 4 4 ) = 8 8 . 5 5 , MSe = 0.0 08, 17 4 . 2 5 , p s < . 05 ) , a n d ( b ) t h es i m p l e i n t e r ac t i o n o f e n c o d i n g a n d r e t r ie v a l m o o d s h a d ar e l a t i v e l y w e a k i n f l u e n c e o n t h e r e c a l l o f r e a d i t e m s , F ( I , 4 4 )= 4 . 0 7 , MS, = 0 . 0 0 3 , p = . 0 5, w i t h t h e h a p p y / h a p p y c o n d i t i o nh o l d i n g a s i g n i f i c a n t , b u t l e s s t h a n s t r i k i n g , a d v a n t a g e o v e rb o t h t h e h a p p y / s a d a n d s a d / h a p p y c o n d i t i o n s ( F s > 3 .9 0 , p s< . 0 5 ). T a k e n to g e th e r , t h e s e r e s u l t s s q u a re w i th th e p o s s ib i l -i t y , p o s e d i n t h e o p e n i n g s e c t i o n , t h a t m o o d d e p e n d e n t e f f e c tsi n m e m o r y m a y b e m o r e p r o n o u n c e d f o r i n t e r n a l t h a n f o re x t e r n a l e v e n t s .

E a r l i er i t w a s r e m a r k e d t h a t r a t i n g s o f m o o d w e r e c o r r e l a te dw i t h t h o s e o f a r o u s a l , s o t h a t h a p p y s u b j e c t s w e r e m o r e h i g h l ya r o u s e d t h a n w e r e s a d s u b j e c t s . N e v e r t h e l e s s , i n s p e c t i o n o ft h e r a t i n g s s u p p l i e d b y s u b j e c t s a s s i g n e d t o t h e m i s m a t c h e dm o o d c o n d i t i o n s ( v iz ., e n c o d e h a p p y / r e t r i e v e s a d o r e n c o d es a d / r e t r i e v e h a p p y ) s u g g e s t e d t h a t a l t h o u g h a l l o f t h e s e s u b -j e c t s s h o w e d a s u b s t a n t i a l sh i f t i n m o o d b e t w e e n t h e e n c o d i n ga n d r e t r i e v a l s e s s io n s ( a s w a s m a n d a t e d b y o u r m e t h o d s ) ,o n l y s o m e m a n i f e s t e d a m a r k e d c h a n g e i n a r o u s a l a s w e l l .T h i s b e i n g s o , i t is m e a n i n g f u l t o a s k : D o e s a c h a n g e i n b o t hm o o d a n d a r o u s a l i m p a i r i t e m r e c a l l m o r e t h a n d o e s a c h a n g ei n m o o d a l o n e , a n d i f s o , i s t h i s i m p a i r m e n t s p e c i fi c t o t h er e c a l l o f g e n e r a t e d a s o p p o s e d t o r e a d i t e m s ?

T o a d d r e s s t h e s e q u e s t io n s , w e d e r i v e d t w o s c o r e s f o r e a c ho f th e 4 8 p a r t i c i p a n t s i n t h e e x p e r i m e n t . O n e o f t h es e s c o r e s - -change in mood--was d e f i n e d a s t h e a b s o l u t e d i f f e r e n c e b e -t w e e n ( a ) t h e m e a n o f t h e m o o d r a t in g s r eg i s te r e d i m m e d i a t e l yb e f o r e a n d i m m e d i a t e l y a f t e r t h e g e n e r a t e / r e a d t a s k ( i . e . ,r a t in g s B E T a n d A E T i n T a b l e 1 ) a n d ( b ) t h e m e a n o f th em o o d r a t in g s r eg i s te r e d i m m e d i a t e l y b e f or e a n d i m m e d i a t e l ya f t e r t h e t e s t o f i t e m r e c a l l ( i .e . , r a t i n g s B R c a n d A R c ) . T h es e c o n d score--change in arousal--was d e f i n e d t h e s a m e w a y ,e x c e p t t h a t r a t i n g s o f a r o u s a l s u b s t i t u t e d f o r t h o s e o f m o o d .

N e x t , w e d i v i d e d t h e 2 4 r e p r e se n t a t iv e s o f th e m i s m a t c h e dm o o d c o n d i t i o n s in t o t w o g r o u p s: large change in mood/largechange in arousal ( th e 1 2 s u b je c t s w i th th e l a rg e s t a ro u s a lc h a n g e s c o r e s ) a n d large change in mood/small change inarousal ( t h e 1 2 s u b j e c t s w i t h t h e s m a l l e s t a r o u s a l c h a n g es c o re s ). F o r p u r p o s e s o f c o m p a r i s o n , a t h i r d group--smallchange in mood/small change in arousal--was f o r m e d , w h i c hc o n s i st e d o f t h e 2 4 r e p r e s e n t at i v e s o f t h e m a t c h e d - m o o dc o n d i t i o n s ( v i z . , e n c o d e h a p p y / r e t r i e v e h a p p y a n d e n c o d es a d / r e t r i e v e s a d ) , m o s t o f w h o m d i s p l a y e d l i tt l e , i f a n y , d i s -p a r i t y b e t w e e n s e s s io n s in t h e i r r a t i n g s o f e i t h e r m o o d o ra r o u s a l .


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Table 4P r o b a b il i ty o f R e c a ll a s a F u n c t i o n o f I t e m T y p e a n dM o o d / A r o u s a l C h a n g eItem type

Mood/arousal change n G/1 R/ l G/3 R/3Experiment l

Small (0.3)/small (0.8) 24 .30 .08Large (4.6)/small (1.3) 12 .23 .03Large (4.8)/large (4.1) 12 .11 .06Experiment 2

Small (0.6)/small (1.3) 24 .22 .25Large (5.0)/smaU (1.1) 12 .15 .25Large (5.1)/large (3.1) 12 .12 .21Experiment 3

Small (0.1)/small (1.1) 24 .35 .19Large (4.0)/small (0.9) 12 .33 .09Large (4.9)/large (3.0) 12 .26 .11Experiment 4

Small (0.3)/small (0.7) 24 . l I .36Large (4.9)/small ( 1.1 ) 12 .09 .33Large (4.8)/large (3.8) 12 .05 .25Small (0.5)/small (1.2) 24 .04 .25Large (4.8)/small (l.0) 12 .03 .23Large (5.2)/large (3.9) 12 .03 .25Note. Mean absolute differences between encoding and recall ratingsof mood and of arousal appear in parentheses, n = number of subjectsper mean probability. G/I = once generated; R/I = once read; G/3= thrice generated; R/3 = thrice read.

generality and reliability of the present results are providedby the next three studies in this series.

I tem and source recognit ion. Results of the test of itemrecognition, in the form of me an probabilities with whichgenerated, read, and new items were classified as "old," areshown in Table 5 in relation to encoding and retrieval moods.Though generated items were more often recognized thanwere read items, F(1, 44) = 60.06, M S e = 0.020 , p < .01, thisdifference was unaffected by encoding mood, retrieval mood,or their interac tion (ps > . 10). The influence of these variableson the false re cogni tion of new item s was also negligible (ps> .10).

Table 6 shows the results of the item recognition test inrelation to three conditions of mood/arousal change. Theseconditions were formed in the same fashion as describedearlier in connection with the item recall test (see Table 4),except that in the current context, change in mood (or changein arousal) was defined as the abs olute difference between (a)the mean of the mood (or arousal) ratings registered imme-diately before and immediately after the generate/read task(i.e., ratings BET and AET in Tables 1 and 2) and (b) themean of the mood (or arousal) ratings registered immediatelybefore and immediately after recognition testing (i.e., ratingsARc and ARn). Planned comparisons revealed no reliabledifferences among any of the three conditions of mood/arousal change with respect to the recognition of generated,read, or new items (ps >. 10).

To assess performance in the source recognition test, wedetermine d for every subject both (a) the proportion of gen-erated items correctly called "generated" and (b) the propor-

Table 4 presents the mean measures of mood and arousalchange, plus the mean probabilities of generated and readitem recall, for each of the three groups. With respect to therecall of generated items, analysis by planned comparisonsproduced a clear pattern of results: Subjects who experienceda large change in both mood and arousal were significantlyoutscored by those who experienced an equally large changein mood but a much smaller change in arousal, F(1, 45) =7.73, M S e = 0.011, p < .01, and the la tter subjects were, inturn, marginally outscored by those who experienced a smallchange in moo d as well as arousal (F = 3.20, p < .10). Wi threspect to the recall of read items, however, the pattern isperplexing: The large/large condi tion prod uced slightly bet-ter --n ot significantlyworse--performance than did the large/small condition , whereas performanc e was reliably poorer inthe large/small than in the small/small condition, F(I, 45) =6.69, M S e = 0.003, p = .01.

Let us return to the questions posed earlier: Does a changein both mood and arousal impair item recall more than doesa change in mo od alone, and if so, is this imp airm ent specificto the recall of generated as opposed to read items? In viewof the results summa rized above, the answer to both questionsseems to be yes. This answ er must, however, be regarded withcaution, for two reasons: First, as already noted, mood/arousal change did have a significant, albeit unsystematic,impact on the recall of read items; second, the answer reflectsthe outcome of only one study. Data bearing on both the

Table 5Probabi l i t y o f Recogni t ion a s a Func t ion ~ f l t e m T ype andEncoding /Re tr ieva l Condi t ion

Item typeEncoding/retrievalcondition n G/1 R/1 G/3 R/3 NewExperiment 1

Happy/happy 12 .90 .64 .28Happy/sad 12 .79 .63 .28Sad/happy 12 .85 .62 .32Sad/sad 12 .88 .64 .29Experiment 2

Happy/happy 24 .89 .84 .19Happy/sad 24 .88 .89 .17Experiment 3

Happy/happy 24 .94 .76 .07Happy/sad 24 .93 .77 .09Experiment 4

Happy/happy 24 .85 .94 .12Happy/sad 24 .80 .94 .12Happy/happy 24 .57 .91 .20Happy/sad 24 .53 .82 .19Note. n = number of subjects per mean probability. G/1 = oncegenerated; R/1 = once read; G/3 = thrice generated; R/3 = thriceread.


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450 E R I C E I C H A N D J A N E T M E T C A L F Et i o n o f n e w i t e m s i n c o r r e c t l y c a l le d " g e n e r a t e d . " T h e s e t w op r o p o r t i o n s w e r e t h e n t r a n s l a t e d i n t o a d ' s c o re , s i g n i f y in gt h e s u b j e c t ' s a b i li t y t o d i s c r i m i n a t e t h e s o u r c e o f t a r ge t i t e m st h a t h a d b e e n g e n e r a t e d . A n a n a l o g o u s d ' s c or e , in d e x i n g t h es o u r c e d i s c r i m i n a b i l i t y o f r e a d i t em s , w a s a l so c o m p u t e d f o re a c h s u b j e c t o n t h e b a s i s o f th e p r o p o r t i o n s o f r e a d a n d n e wi t e m s t h a t w e r e i d e n t i f i e d a s h a v i n g b e e n r e a d.M e a n d ' s c o re s r e p r e s e n t i n g t h e s o u r c e d i s c r i m i n a b i l i t y o fg e n e r a t e d a n d r e a d i t e m s a r e f o r m a t t e d a s a f u n c t i o n o fe n c o d i n g / r e t r i e v a l c o n d i t i o n i n T a b l e 7 a n d a s a f u n c t i o n o fm o o d / a r o u s a l c h a n g e i n T a b l e 8 . I n g e n e r a l , s u b j e c t s w e r em o r e a c c u r a t e i n d i s c r i m i n a t i n g th e s o u r c e o f g e n e r a t e d t h a no f r e a d i t e m s , F ( I , 4 4 ) = 7 . 1 4 , MS~ = 1 .0 1 , p = . 0 1 , a n d t h i sw a s t ru e i r r e s p ec t i v e o f e n c o d i n g m o o d , r e t ri e v a l m o o d , o rt h e i r i n t e r a c t i o n ( p s > . 1 0) . S i m i l a r l y , t h e r e w e r e n o s i g n i f i c a n td i ff e re n c es a m o n g t h e t h r e e c o n d i t i o n s o f m o o d / a r o u s a lc h a n g e i n t e r m s o f th e s o u r c e d i s c r i m i n a b i l i t y o f e i t h e r g e n -e r a t e d o r r e a d i t e m s ( p s > . 1 0 ). T h u s , t h e d a t a d i s p l a y e d i nT a b l e s 7 a n d 8 , t o g e t h e r w i t h t h o s e f o u n d i n T a b l e s 5 a n d 6 ,i n d i c a t e t h a t a l t e r a ti o n s o f m o o d o r a r o u s a l d o n o t d i m i n i s hr e c o g n i t i o n o f e i t h e r t h e o c c u r r e n c e o r t h e o r i g i n o f ta r g e te v e n t s , w h e t h e r i n t e r n a l o r e x t e r n a l .

Experiment 2Aims and Method

The f i r s t s tudy showed tha t a sh i f t in mood s ta te impa i red thereca l l o f genera ted i t ems to a g rea te r ex ten t than tha t o f r ead i t ems .I s th is because in te rn a l ly genera ted eve n ts a re pa r t i cu la r ly p rone tomo od dependenc e , a s was suggested a t the ou t se t , o r because the l eve lo f r ead- i tem reca l l was too low (an average o f abou t 6%, as ind ica tedin Tab le 3 ) to a l low as l a rge a mood dependen t e f fec t to emerge inthe reca l l o f r ead i t ems as was ev iden t in the reca l l o f genera ted i t ems?To f ind ou t , we con duc ted a second s tudy tha t was iden t ica l to thefirs t in al l respects save three. First , in an effort to enh anc e the recal lo f r ead i t ems re la t ive to tha t o f genera ted i t ems , sub jec t s in the seconds tudy were p resen ted , a t encod ing , wi th 16 i t ems to read th ree t im eseach , and w i th 16 i t ems to genera te one t ime each . R epe t i t ions o f thesame i t em to read were spaced a t r ando m th roug hout the p resen ta t ionl i s t , and any i t em tha t was th r ice read by one sub jec t was onceg e n e r at e d b y a n o t h e r . B o t h t h e m a n n e r i n w h i c h r e a d a n d g e n e r a te di tems were p resen ted a t encod ing , and the na tu re o f the i t ems them-selves, were the sam e as previou sly described.Second , the Alpha Chamber , in which sub jec t s in the f i r s t s tudysa t whi le they l i s t ened to mus ic , was re tu rne d to the co l league f romw h o m w e h a d b o r r o w e d i t, a n d w a s r ep l a c ed w i t h a m o r e c o n v e n -t iona l lounge cha i r. M us ic was p layed to pa r t i c ipan t s in the seco nds tudy v ia two h igh-qua l i ty s te reo speakers, which were s i tua ted one i the r s ide o f th i s cha i r .Th i rd , because the moo d dep ende n t e ffect found in the f i r s t s tudywas symmet r ic in fo rm-- tha t i s , encode happy / re t r i eve sad sub jec t spe r fo rmed as po or ly in reca l l a s d id the i r encode sad / re t r i eve hap pycoun te rpar t s ( see Tab le 3 fo r the re levan t da ta , and E ich , 1989, fo r at h e o re t ic a l d i s cu s s i on o f s y m m e t r i c a n d a s y m m e t r i c f o r m s o f m o o ddependence) - - the des ign o f the second s tudy was s impl i f i ed , suchtha t som e sub jec t s comple ted bo th the e ncod ing and re t r ieva l sessionsi n a h a p p y m o o d , w h e r e as o t h e r s w er e h a p p y d u r i n g e n c o d i n g a n dsad dur ing re t r i eva l. Each o f these two enc od ing / re t r i eva l cond i t ions( m a t c h e d v s . m i s m a t c h e d m o o d ) w a s r e p r e s e n t e d b y 2 4 r a n d o m l yass igned sub jec t s, al l o f who m were UB C undergradua tes .

T a b l e 6Probability of Recognition as a Function of Item Type andMood/Arousal ChangeI t e m t y p e

M o o d / a r o u s a l c h a n g e n G / 1 R / I G / 3 R / 3 N e wE x p e r i m e n t 1

Smal l (0 .9 ) / sma l l ( l .0 ) 24 .89 .64 .28Large (3.7 )/sm all (0.9) 12 .82 .60 .29Larg e (4.3)/la rge (4.1) 12 .82 .65 .31E x p e r i m e n t 2

Sm all ( l .2) /s ma U (1.5) 24 .89 .84 .19Large (4.0 )/sm all (0.6) 12 .91 .91 .17Large (4.4)/l arge (3.0) 12 .84 .88 .16E x p e r i m e n t 3

Sm all (0.8)/sm all (1.4) 24 .94 .76 .07Large (2.6 )/sm all (0.6) 12 .91 .73 .12Large (3.6)/l arge (2.3) 12 .94 .80 .07

E x p e r i m e n t 4Sm all (0.8)/sm all (0.7) 24 .85 .94 .12Large (4.0 )/sm all(0.8 ) 12 .81 .96 .10Large (3.8 )/large (3.1) 12 .79 .93 .14Sm all (0.9)/sm all (1.5) 24 .57 .91 .20Large (3.8 )/sm all(0.6 ) 12 .56 .85 .18Large (4.3 )/large (3.2) 12 .50 .79 .21

Note, Me an abso lu te d if fe rences be tween encod ing and recogn i t ionr a ti n g s o f m o o d a n d o f a r o us a l a p p e a r i n p a r e nt h e se s , n = n u m b e r o fsub jec t s pe r mea n p robab i l i ty . G /1 = once genera ted ; R /1 = o nceread ; G/ 3 = th r ice genera ted ; R /3 = th r ice read .

ResultsMood and arousal ratings. R e s u l t s p e r t a i n i n g t o r a t i n g s

o f m o o d a r e p r e s e n t e d i n T a b l e 1. I n s p e c t i o n o f th e s e r e su l t si n d i c a t e s t h a t t h e s u b j e c t s w e r e s l i g h t ly h a p p y a t t h e s t a r t o ft h e e n c o d i n g s e s s i o n ( m e a n E S B r a t i n g = 1 . 0, n = 4 8 ) , v e r yh a p p y w h e n t h e y b e g a n t h e t a s k o f g e n e r a t i n g a n d ( r e p e a t e d ly )r e a d i n g w o r d s ( m e a n B E T r a t i n g = 3 . 1) , a n d m o d e r a t e l yh a p p y b y t h e t i m e t h e y h a d f i n is h e d ( m e a n A E T r a t in g =2 . 3) . T h i s p a t t e r n o f e n c o d i n g s e s s io n r a t i n g s p a r a ll e ls t h e o n ef o u n d f o r h a p p y s u b j e c t s i n t h e f i r s t s t u d y .

T h o u g h m a t c h e d a n d m i s m a t c h e d m o o d s u b j e c ts w e r ee q u i v a l e n t l y h a p p y a t t h e b e g i n n i n g o f t h e r e t ri e v a l se s s io n( m e a n R S B r a t i n g = 1 .1 , n = 4 8 ), t h e i r r a t i n g s o f m o o dd i f f e r e d m a r k e d l y t h e r e a f t e r . O n a v e r a g e , t h e f o r m e r s u b j e c t so u t s c o r e d t h e l a t t e r b y 6 . 2 p o i n t s o n t h e 9 - p o i n t h a p p i n e s s /s a d n e s s s c a l e p r i o r t o i t e m r e c a l l ( r a t i n g B R c ) , b y 3 . 8 p o i n t sp r i o r t o i t e m r e c o g n i t i o n (r a t i n g A R c ) , a n d b y 3 . 1 p o i n t s a tt h e c o n c l u s i o n o f s o u r c e r e c o g n i t i o n ( r a t i n g A R n ) . A l l o f th e s ed i f f e r e n c e s w e r e s i g n i f i c a n t , t s ( 4 6 ) > 1 0 . 0 5 , p s < . 0 1 , w h i c hr e a f f i r m s t h e c o n c l u s i o n , r e a c h e d i n t h e f i rs t s t u d y , t h a t t h ec o n t i n u o u s m u s i c t e c h n i q u e p r o d u c e d s t a ti s ti c a ll y r e l ia b l ea n d r e l a ti v e l y s t a b le m o d i f i c a t i o n s o f m o o d .

D a t a r e l a t in g t o r a ti n g s o f a r o u s a l a p p e a r i n T a b l e 2 .C o m p a r i s o n o f th e s e d at a w i t h t h e m o o d r a ti n g s s u m m a r i z e d


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Table 7Discr iminabi l it y (d ' ) o f Source (Exper iment s I - 3) orFrequency (Exper iment 4 ) as a Fun c t ion o f I t emType and Encod ing/Re t r i eva l Condi t ionItem typeEncoding/retrieval

condition n G/1 R/1 G/3 R/3Experiment 1

Happy/happy 12 2.63 1.94Happy/sad 12 2.47 1.81Sad/happy 12 2.44 1.69Sad/sad 12 2.06 1.96Experiment 2

Happy/happy 24 3.04 2.77Happy/sad 24 3.01 2.85Experiment 3

Happy/happy 24 3.51 3.38Happy/sad 24 3.31 3.30Experiment 4

Happy/happy 24 2.84 2.99Happy/sad 24 3.08 3.18Happy/happy 24 2.17 2.58Happy/sad 24 2.48 2.21Note. n = number of subjects per mean d'. (3/1 = once generated;R/I = once read; G/3 = thrice generated; R/3 = thrice read.

in Table 1 suggests that, as was the case in Experiment 1,ratings of arousal tended to covary with those of mood. Themea n correlation between the seven principal pairs of ratingsmade by subjects in E xperimen t 2 was .34, which significantlyexceeds zero, t(47) = 4.77 , p < .01.I t em reca l l . The average error rate in the g eneration taskwas 5.6%; items con tribut ing to this average were excludedfrom analyses of recall and recognition performance.

The mean probabilities with which once-generated andthrice-read items were recalled are presented in Table 3. Thesimple effects of encoding/retrieval conditi on and item typewere both significant, indicating an advantage of matchedover mismatc hed moods, F(I, 46) = 5.68, M So = 0.010, p . 10), theydiffered with respect to the recall of generated items. Specifi-cally, subjects who experienced a small change between ses-sions in mood as well as arousal recalled more generated itemsthan did subjects who experienced either a large change inboth mood and arousal, F(1, 45) = 8.76, M Se = 0.009, p . 1 0 ).

I n r e f e re n c e t o T a b l e 4 , p l a n n e d c o m p a r i s o n s s h o w e d t h a ts u b j e c t s w h o e x p e r i e n c e d a l a r g e a s o p p o s e d t o a s m a l l s h if ti n b o t h m o o d a n d a r o u s a l r e c a l le d f e w e r o n c e - g e n e r a t e di t e m s , F ( 1 , 9 0 ) = 5 . 7 4 , M S e = 0 . 0 0 5 , p < . 0 5 , a n d f e w e rt h r i c e - g e n e r a t e d it e m s , F ( 1 , 9 0 ) = 7 . 1 9 , MSe = 0.013, p < .01.A l l o t h e r c o m p a r i s o n s w e r e n o n s i g n i f i c a n t ( F s < 2 . 4 8 , p s >.1 0 ) .I t em and f r equen cy recogni tion . W i t h r e s p e c t t o T a b l e 5 ,a 2 x 2 x 2 ( E n c o d i n g / R e t r i e v a l M o o d x I t e m T y p e x I t e mF r e q u e n c y ) a n a l y s i s r e v e a l e d t h a t t h e p r o b a b i l i t y o f a r e c o g -n i t i o n h i t w a s g r e a t e r f o r g e n e r a t e d t h a n f o r r e a d i t e m s , F ( I ,9 2 ) = 5 2 .8 5 , M S e = 0 . 0 2 9 , p < . 0 1 , a n d g r e a t e r f o r t h r i c e -p r e s e n t e d t h a n f o r o n c e - p r e s e n t e d t a rg e t s , F ( 1 , 9 2 ) = 1 3 2 .7 2 ,M S e = 0 . 0 1 7 , p < . 0 1. T h e i n t e r a c t i o n b e t w e e n t h e s e v a r ia b l e sw a s s i g n i f i c a n t , F ( 1 , 9 2 ) = 2 7 . 5 4 , M S e = 0 .0 1 7 , p < . 0 1 ,i n d i c a t i n g th a t t h e a d v a n t a g e i n r e c o g n i t i o n o f g e n e r a t e d o v e rr e a d i t e m s w a s m a g n i f i e d i f b o t h t y p e s o f i t e m s h a d b e e np r e s e n t e d o n c e r a t h e r t h a n t h r i c e. O d d l y , t h e o v e r a l l r e c o g -n i t i o n - h i t r a te a t t a i n e d b y s u b j e c t s w h o s e e n c o d i n g a n d r e -t r ie v a l m o o d s m a t c h e d w a s m a r g i n a l l y a b o v e t h at a c h i e v e db y s u b j e c t s w h o s h i f te d f r o m h a p p i n e s s t o s a d n e s s , F (1 , 9 2 ) =3 . 6 3 , M S~ = 0 . 0 2 9 , p < . 1 0. I t i s u n c l e a r w h y t h i s s t u d y s h o u l ds h o w s o m e s e m b l a n c e o f m o o d d e p e n d e n t r e c o g n i ti o n w h e nn o n e o f t h e o t h e r s d i d . R e a s s u r i n g l y , t h e o v e r a l l fa l s e - p o s i ti v er a t e w a s u n a f f e c t e d b y e n c o d i n g / r e t r i e v a l c o n d i t i o n ( F < 1 ),t h o u g h i t w a s h i g h e r i f s u b j e c t s r e a d r a t h e r t h a n g e n e r a t e dt a r g e t i t e m s d u r i n g t h e e n c o d i n g s e s s io n , F ( 1 , 9 2 ) = 7 . 5 1, M S~= 0 .0 2 0 , p < . 0 1 ) .

W i t h r e s p e c t to T a b l e 6 , a n a l y s is b y p l a n n e d c o m p a r i s o n sd i s c l o s e d o n l y o n e s i g n i f ic a n t d i ff e r e n c e: S u b j e c t s w h o e x p e -r i e n c e d a l a r g e c h a n g e i n m o o d a s w e ll a s a r o u s a l r e c o g n i z e df e w e r t h r i c e - r e a d it e m s t h a n d i d s u b j e c t s w h o e x p e r i e n c e d as m a l l c h a n g e i n b o t h m o o d a n d a r o u s a l , F ( 1 , 9 0 ) = 7 . 4 4 , M S e= 0 . 0 1 6 , p < . 01 . I n a s m u c h a s n o c o m p a r a b l e d i f f e r e n c e w a sd e t e c t e d i n e i th e r E x p e r i m e n t 2 o r E x p e r i m e n t 3 , t h e s i g n if i -c a n c e o f t h e p r e s e n t r e s u l t i s p r o b a b l y i l l u s o r y .

M e a n d ' s c o r e s d e r i v e d f r o m t h e t e s t o f f r e q u e n c y r e c o g -n i t i o n a r e a r r a n g e d i n r e l a t i o n to e n c o d i n g / r e t r i e v a l c o n d i t i o na n d m o o d / a r o u s a l c h a n g e i n T a b l e s 7 a n d 8 , r e s p e c ti v e l y .T w o d ' s c o r e s w e r e c o m p u t e d f o r e v e ry s u b je c t , o n e o f w h i c hw a s b a s e d o n ( a ) t h e p r o p o r t i o n o f o n c e - g e n e r a t e d o r o n c e -r e a d i t e m s t h a t t h e s u b j e c t c o r r e c t ly c l a ss i f ie d a s h a v i n g b e e np r e s e n te d o n e t i m e a n d ( b ) t h e p r o p o r t i o n o f n e w i t e m s t h a tt h e s u b j e c t i n c o r r e c t l y c l a s si f ie d a s h a v i n g b e e n o n c e p r e -s e n t e d . T h e s e c o n d d ' s c o r e r e fl e c t e d t h e f r e q u e n c y d i s c r i m i -n a t i o n o f th r i c e - g e n e r a t e d o r t h r i c e - r e a d i te m s , a n d w a s b a s e do n t h e p r o p o r t i o n s o f t h r ic e - p r e s e n te d a n d n e w i t em s t h a tw e r e i d e n t i f i e d a s h a v i n g b e e n p r e s e n t e d t h r e e t i m e s .

R e l a t i v e to s u b j e c t s w h o r e a d t a r g e t i t e m s d u r i n g t h e e n -c o d i n g s e s si o n , t h o s e w h o g e n e r a t e d t h e m w e r e m o r e a c c u r a t ei n d i s c r i m i n a t i n g t h e f r e q u e n c y w i t h w h i c h t h e t a r g e t s h a d

b e e n p r e s e n t e d , F ( 1 , 9 2 ) = 1 5 . 8 0 , M S e = 1 .35 , p < .01 .A c c u r a c y o f d i s c r i m i n a t i o n w a s n o t a f f e c te d b y i t e m f r e -q u e n c y , e n c o d i n g / r e t r i e v a l c o n d i t i o n , o r t h e i r i n t e r a c t i o n ( F s< 1 ), a n d t h e r e w e r e n o d i f fe r e n c e s a m o n g t h e t h r e e c o n d i t i o n so f m o o d / a r o u s a l c h a n g e ( p s > . 1 0).

G e n e r a l D i s c u s s i o nW e w i l l f r a m e t h e d i s c u s s i o n o f t h i s s e ri e s o f s t u d ie s a r o u n d

f o u r p r i n c i p a l p o i n t s . F i r st , t h e p r e s e n t r e s u lt s p r o v i d e g o o d - -n o t g r e a t - - s u p p o r t f o r t h e p r o p o s i t i o n t h a t e v e n ts t h a t a r eg e n e r a t e d t h r o u g h i n t e r n a l m e n t a l p r o c e s s e s s u c h a s r e a s o n -i ng , i m a g i n a t io n , a n d t h o u g h t m a y b e m o r e c o l o r e d b y o rc o n n e c t e d t o o n e ' s c u rr e n t m o o d t h a n a r e t h o s e th a t e m a n a t ef r o m e x t e r n a l s o u r c e s , t h e r e b y l e a d i n g t o a l a r g e r l o s s o fm e m o r y f o r in t e r n a l t h a n f o r e x t e r n a l e v e n ts a f t e r a s h i f t i nm o o d s t a t e . W e s a y t h e s u p p o r t i s " n o t g r e a t " f o r t h e s i m p l er e a s o n t h a t , f r o m a s t a t i s ti c a l s t a n d p o i n t , o n l y t h e f i rs t t w o o ft h e f o u r s t u d i e s s h o w e d t h a t t h e r e c a l l o f g e n e r a t e d i t e m s w a ss i g n i f ic a n t l y m o r e i m p a i r e d b y a s h i f t i n m o o d t h a n w a s t h er e c a ll o f r e a d i t e m s . W h a t i s m o r e , i n o n e o f t h e s t u d i e s( E x p e r i m e n t 3 ) , t h e a d v a n t a g e i n r e c a l l o f m a t c h e d o v e rm i s m a t c h e d m o o d c o n d i t i o n s w a s s l ig h t ly g r e a te r f o r r e a dt h a n f o r g e n er a t e d i t e m s - - t h e a n t i th e s i s o f th e a n t i c i p a t e dp a t t e r n o f r e s u l ts .

S t il l, a c a s e f o r " g o o d " s u p p o r t c a n b e m a d e , e s p e c i a l ly i ft h e f o u r s t u d i e s a r e c o n s i d e r e d c o l l e c t iv e l y r a t h e r t h a n s e p a -r a t e ly . T o t h i s e n d , w e r e a p p o r t i o n e d t h e r e c a l l d a t a i n s u c ha w a y t h a t e a c h o f t h e 1 44 s u b j e c t s w h o s e r v e d i n e i t h e rE x p e r i m e n t 1 , 2 , o r 3 c o n t r i b u t e d t w o s c o r e s ( o n e r ef l e c ti n gt h e r e c a l l o f o n c e - o r t h r i c e - g e n e r a t e d it e m s , a n d t h e o t h e r ,t h e r e c a l l o f o n c e - o r t h r i c e - r e a d i t e m s ) , w h e r e a s e a c h o f t h e9 6 p a r t i c i p a n t s i n E x p e r i m e n t 4 s u p p l i e d a s i n g le s c o re ( t h em e a n p r o b a b i l i t y o f r e c a ll o f e i th e r o n c e - a n d t h r i c e - g e n e r a t e do r o n c e - a n d t h r i c e - r e a d i te m s ) . T h e t o t a l n u m b e r o f o b s e r-v a t i o n s , th e n , w a s 3 8 4 , o f w h i c h h a l f p e r t a i n e d t o t h e r e c a l lo f g e n e r a t e d i t e m s a n d h a l f t o t h e r e c a l l o f r e a d i t e m s . W i t h i ne a c h t y p e o f i t e m , h a l f o f t h e o b s e r v a t i o n s c o r r e s p o n d e d t om a t c h e d m o o d c o n d i t i o n s (e i th e r e n c o d e h a p p y / r e t r ie v eh a p p y o r e n c o d e s a d / r e tr i e v e sa d ), a n d h a l f t o m i s m a t c h e dm o o d c o n d i t i o n s ( e n c o d e h a p p y / r e t r i e v e s a d o r t h e re v e r se ) .

T h e a g g r e g a te d a t a a p p e a r i n T a b l e 9 . A n a l y s i s o f t h e s e d a t as h o w e d t h a t t h e s i m p l e e f fe c t s o f e n c o d i n g / r e t r i e v a l c o n d i t i o na n d i t e m t y p e w e r e s i g n i f ic a n t , F s ( l , 3 8 0 ) > 2 7 . 5 7, M S e =0 . 0 1 2 , p s < . 0 1 , a s w a s t h e i r i n t e r a c t i o n , F ( 1 , 3 8 0 ) = 3 . 7 6 , pT a b l e 9P r o b a b il i ty o f R e c a l l a s a F u n c t i o n o f l t e m T y p e a n dEncoding /Re tr ieva l Condi t ion ( Exper iments1 - 4 C o m b i n e d )

I t e m t y p eE n c o d i n g / r e t r i e va lc o n d i t i o n n G e n e r a t e d R e a dMatche d mo ods 96 .28 .16M i s m a t c h e d m o o d s 9 6 . 19 . 1 3

Note. n = n u m b e r o f su b je c ts p e r m e a n p r o b a b i l i t y . M a t c h e d m o o d sc o r r e s p o n d t o e n c o d e h a p p y / r e t r i e ve h a p p y a n d e n c o d e s a d / r e t ri e ves a d c o n d i t i o n s ; m i s m a t c h e d m o o d s c o r r e s p o n d t o e n c o d e h a p p y /r e t ri e ve s a d a n d e n c o d e s a d / r e t ri e ve h a p p y c o n d i t io n s .


12/13

4 5 4 E R I C E I C H A N D J A N E T M E T C A L F E= . 0 5. W h e r e a s m a t c h e d a n d m i s m a t c h e d m o o d c o n d i t i o n sd i f f e r e d b y 3 % i n t h e r e c a l l o f r e a d i t e m s , F ( 1 , 3 8 0 ) = 5 . 4 9 , p< . 0 5, t h e y d i f f e r e d b y 9 % i n t h e r e c a l l o f g e n e r a t e d i t e m s ,F ( I , 3 8 0 ) - -- 2 5 . 8 5 , p < . 0 1 . N e i th e r o f t h e s e d i f f e re n c e s i sp a r t i c u l a rl y i m p r e s si v e , b u t t h e y d o i m p l y t h a t i n t e r n a l e v e n t sa r e m o r e a p t t o b e r e n d e r e d u n r e c a l l a b le in t h e t r a n s i t i o nf r o m o n e m o o d s t a t e t o a n o t h e r .A l t h o u g h t h e s o u r c e o f a n e v e n t s e e m s t o p l a y a p a r t i n t h eo c c u r r e n c e o f m o o d d e p e n d e n t m e m o r y , i t i s n o t t h e o n l yf a c t o r t h a t m a t t e r s , o r e v e n t h e o n e t h a t m a t t e r s m o s t . T h i s ,t h e s e c o n d m a i n p o i n t , i s p l a i n l y i l l u s t r a t e d b y t h e f a c t t h a to f t h e s e v er a l te s ts o f r e t e n t i o n - - f r e e r e c al l , it e m r e c o g n i ti o n ,a n d s o u r c e o r f r e q u e n c y d i s c r i m i n a t i o n - - t h a t w e re t a k e n b ys u b j e c t s i n t h i s r e s e a r c h , o n l y f r e e r e c a l l a f f o r d e d c o n s i s t e n te v i d e n c e o f m o o d d e p e n d e n c e . P e r h a p s th e m o r e o n e m u s tr e l y o n i n t e r n a l r e s o u r c e s , r a t h e r t h a n e x t e r n a l a i d s , t o g e n -e r a t e b o t h t h e t a r g e t e v e n t s a t e n c o d i n g a n d t h e c u e s r e q u i r e df o r t h e i r r et r i e v a l , t h e m o r e l i k e l y is o n e ' s m e m o r y f o r t h e s ee v e n t s t o b e m o o d d e p e n d e n t . I n a n y c a se , th e f i n d i n g th a td e s e r v e s e m p h a s i s i s t h a t m o o d d e p e n d e n t e f f e ct s a r e d e t e r -m i n e d n o t o n l y b y t h e s o u r c e o f th e t a r g e t e v e n t s ( i n t e r n a l v s.e x t e r n a l ) , b u t a l s o b y t h e m a n n e r i n w h i c h r e t e n t i o n i s m e a s -u r e d .T h e t h i r d i s s u e o f i n t e r e s t h a s t o d o w i t h t h e s t r e n g t h a n ds t a b i li t y o f t h e m o o d s i n w h i c h e n c o d i n g a n d r e t r ie v a l t a k ep l a c e . I n t u i t i o n s u g g e s t s t h a t i n o r d e r t o s h o w t h a t a s h i f t i nm o o d s t a te s i g ni f i ca n t l y i m p a i r s m e m o r y , t w o c o n d i t i o n sm u s t b e s a t is f i ed . F i r s t, t h e s h i f t m u s t b e s u b s t a n t i a l . J u s t hows u b s t a n t i a l is a n o p e n e m p i r i c a l q u e s t i o n , b u t b a s e d o n t h ep r e s e n t r e s u l t s , i t s e e m s t h a t t h e s h i f t f r o m a very happy t o avery sad s t a t e ( o r v i c e v e r s a ) i s su f f i c i e n t to r e d u c e t h e r e c a l lo f i n t e r n a l l y g e n e r a t e d e v e n t s . I t i s p o s s ib l e , i n d e e d p r o b a b l e ,t h a t a l e s s s e v e r e s h i f t - - s a y f r o m f e e l i n g slightly happy t ofe e l in g slightly sad--would h a v e n o s i g n if i c an t i m p a c t o n t h er e c a l l o f e v e n t s, e v e n t h o s e t h a t h a d b e e n p r o d u c e d i n t e r n a l l y .S e c o n d , t h e m o o d t h a t e x i st s a t t h e s t a r t o f t h e e n c o d i n g o rr e t r i e v a l t a s k m u s t s t i ll b e p r e s e n t a t i t s e n d . T h e i m p o r t a n c eo f t h i s p r o v i s o i s i m p l i e d b y t h e r e s u l t s o f a s m a l l p i l o t s t u d y ,i n w h i c h w e s o u g h t t o m a n i p u l a t e m o o d u s i ng t he V e l t en( 1 9 6 8 ) t e c h n i q u e , w h e r e b y s u b j e c t s a r e a s k e d t o i n t e r n a l i z et h e a f f e c t s u g g e s t ed b y a s e r ie s o f e l a t i o n o r d e p r e s s i o n s t a t e -m e n t s . S u b j e c t s i n t h i s s t u d y ( 1 6 U B C u n d e r g r a d u a t e s ) u n -d e r t o o k a g e n e r a t e / r e a d t a s k, s i m i l a r to t h e o n e u s e d i nE x p e r i m e n t 1, a f t e r th e i n d u c t i o n o f e i th e r a n e l a te d o r ad e p r e s s e d m o o d , a n d w e r e t e s t e d f o r f r e e r e c a l l 3 0 r a i n l a t e ri n e i t h e r t h e o r i g i n a l o r t h e o p p o s i t e s t at e .

R e l a t i v e t o s u b j e c t s w h o r e c e i v e d t h e d e p r e s s i o n i n d u c t i o n ,t h o s e e x p o s e d t o s t a t e m e n t s s u g g e s t i n g e l a t i o n r a t e d t h e m -s e l v es a s b e i n g s i g n i f i c a n t l y h a p p i e r i m m e d i a t e l y before t h e yb e g a n b o t h t h e g e n e r a t e / r e a d a n d t h e i t e m r e c al l t a s k s ( m e a nra t in g s o f 5 . 2 v s . 3 .0 o n a 7 -p o i n t s c a l e ) , t(1 4 ) - -- 5 . 0 8 , p < . 0 1 .H o w e v e r , t h e r e w a s n o r e l i a b l e d i f f e r e n c e b e t w e e n e l a t i o n a n dd e p r e s s io n i n d u c t i o n s i n h a p p i n e s s r a t in g s r e g i st e r ed i m m e -d i a t e l y after t h e p e r f o r m a n c e o f e i t h er t a s k ( m e a n s o f 4 .8 v s.4 . 6 ; t < 1 ). T h u s , t h e e f f e c t s o f t h e V e l t e n t e c h n iq u e o n s e l f -r e p o r t e d h a p p i n e s s , t h o u g h s t r o n g i n i t i a l l y , p r o v e d t o b e s h o r tl i v e d ( f o r s i m i l a r r e s u l t s , s e e I s e n & G o r g o g l i o n e , 1 9 8 3 ) .P e r h a p s f o r t h is r e a s o n , o u r p i l o t s t u d y p r o v i d e d n o e v i d e n c eo f m o o d d e p e n d e n c e i n t h e r e c a ll o f e i t h e r g e n e r a t e d o r r e a d

i t e m s ( m e a n p r o b a b i l i t i e s o f . 3 3 a n d . 1 0 u n d e r m a t c h e d m o o dc o n d i t i o n s ; . 39 a n d . 0 9 u n d e r m i s m a t c h e d m o o d c o n d i t i o n s) .B e c a u se t h e m o o d e f fe c ts en g e n d e r e d b y t h e c o n t i n u o u s m u s i ct e c h n i q u e a r e r e a s o n a b l y s t a b l e o v e r t i m e a n d a c r o s s t a s k s( s e e T a b l e 1 ), a n d b e c a u s e f a r m o r e p e o p l e a r e r e s p o n s i v e t ot h e m u s i c a l t h a n t o t h e V e l t e n i n d u c t i o n ( s ee C l a r k , 1 9 83 ) ,t

1989 Eich & Metcalfe 1989 Mood Dependent Memory for Internal Versus External Events

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Transcript of 1989 Eich & Metcalfe 1989 Mood Dependent Memory for Internal Versus External Events