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Mood state-Dependent Retrieval: The Effects of Induced Mood on Memory
Reconsidered
Pamela M. Kenealy
Online publication date: 22 October 2010
To cite this Article Kenealy, Pamela M.(1997) 'Mood state-Dependent Retrieval: The Effects of Induced Mood on Memory
Reconsidered', The Quarterly Journal of Experimental Psychology Section A, 50: 2, 290 — 317
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TH E QUARTE R LY JOU RNAL O F E XPE R IM E NTAL PS YCH OL OG Y, 1997, 50A (2), 290± 317
M ood-state± D epen dent Retrieval: T he E ffects
of Ind uced M ood on M em ory Reconsidered
P amela M . K enealy
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School of P sychology, R oeha mpton I nstitute London
A n alysis of stu d ies inve stig ating m ood -state ± d ep end en t retrieval iden ti® es m eth od ological
pro blem s th at m ay h ave con trib uted to th e con trov ersy s ur ro u n d ing th e reliability of th e
effectÐ in p ar ticu lar, th e p ossible con fou n d ing of en cod ing an d retrieval in p revious stud ies.
Five exp erim ents are repo r te d investigating th e effects of m ood on lear n ing an d r ec all.
M ood -state ± d ep end en t retrieval w as obser ve d in E xp erim ent 1a (usin g Velten ’ s M ood
Indu ction Pro ced u re); E xp erim en t 1b (u sin g a m usic M IP); an d E xp erim en t 1c (u sin g
Velten’ s M IP at encod ing and a mu sic M IP at retrieval). S u bje cts w h o lear n ed an d r ec alled
in d ifferent m ood s h ad sign i® can tly g reater d ecrem ents in recall th an d id su bjects in the sa m e
m oo ds. E xp erim en ts 2 an d 3 investigated th e effect of observ able retrieval cu es on m ood state± d ep end en t retrieval. In E xp erim ent 2, th e p re sen ce of observ able r etrieval cu es at recall
over ro de sta te-d ep end en t retrieval. In E xp erim en t 3, by m an ipu lating th e p resen ce or
absen ce of obser vable cu es at recall, both th e occ ur ren ce an d th e erasu re of the m ood-state
dep en d enc y w as d em on strate d . M oo d state du rin g lear n ing an d cu ed recall w as also sho w n to
affect p erfo r m anc e in a th ird sessio n u n d er con d iton s of free recall.
T here is consider able co ntroversy su rrounding the state-d ep end ent effects of m ood o n
m em ory (see B laney, 1986; K uiken, 1991). M ood-state± dependent retrieval has im portant
implicatio ns for theories of co ntext effects in m em ory (B add eley, 1982; Bow er, 1981,
D avies & T h om son, 1988; E ich, 1989; Tulving, 1983; Tulving & T hom son, 1971,
1973 ) an d th eories of d epression (B eck, 1976; Blaney, 1986; Ing ram , 1984; Reus,
Weing ar tner & Post, 19 79; Teasdale, 1983), but dem onstrations of the phenom eno n seem
to b e elusive an d unpredictable an d present som e em bar rassm ent for these theories. In a
critical review of the literature on affect an d m em ory, Blaney (1986) has noted that alth ough
the literatu re dem onstrating state-depen den ce involvin g drug-induced states is considerable, there are few relevan t studies involving elated or depressed m ood. O ther reviewers
have noted th at the evid ence for the presence or absen ce of m ood-state dependency rem ains
highly equivocal, w hereas the evid ence fo r m ood cong ruency is stron g (Bad deley, 1990;
Bower & M ayer, 1991; E ich, 1989; E llis & A shbrook, 1991). B ow er (1987) claim s to have
been ``unable to ® gure out an ything system atic that cau ses these con¯ ictin g results’ ’ (p. 451).
Bower confesses to not having carefully inspected all the varying proced ures of the
Requ ests for re prin ts sh ould be sen t to Pam e la K enealy, S chool of Psycho logy, Roeh am pton Institu te L ond on ,
W hiteland s C ollege, West H ill, Lo ndon SW 15 3SN, U.K .
Ó
1997 The E xp erim ental Psych olog y S ociety
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M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
291
su ccesses an d failures, but co ncludes that ``T he effect seem s a w ill-o’ -the-w isp that
ap pears or not in different experim ents in cap ricious w ays that I do not u nderstand’ ’
(B ow er, 1987, p. 451). K ihlstrom (1991), how ever, sugg ests that no special onus should be
attached to th e m ood m em ory literature sim ply becau se it can not p roduce reliable m ooddependent retrieval. K ihlstrom refers to two oth er classes of experiments, drug-state±
dependent retrieval an d environm ent-dependent m em ory effects, an d concludes that such
effects h ave been dif® cult to ob serve in hum an s under an y circu m stan ces. To recogn iz e
that the effects m ay have lim ited reliability an d be subtle in their operatio n seem s a m ore
useful view, as it m ay per m it a description of these effects w ithin the limits of their
reliability once this has been assessed.
T his pap er prese nts a system atic an alysis of the reported evidence relevan t to the
reliability of laboratory dem o nstratio ns of m ood-state± dependen t retrieval an d highlights
som e of th e problem s that m ay have co ntributed to the controversy surrounding it. Bower
an d M ayer (1991) have concluded that w hat is needed now is som e insightful an alysis of
the reason s, if an y, for th e positive an d neg ative results o n m ood-d ependent retrieval. In
the dom ain of psycholog y, this ® eld is unusual in that th e num ber of pu blished studies
reporting null ® ndings is con siderably g reater th an the num ber reporting positive ® ndings. M ood-state± dependent effects have been reported by Bower, M onteiro, an d G illigan
(1978, Study 3); L eight an d E llis (19 81); S chare, L ishm an , an d Spear (1 984, Study 3);
M ecklenbr au ker an d H ager (1984); an d G age an d Safer (1985 ). E ich an d M etcalfe (1989)
reported m ore pron oun ced m ood-depen den t effects in m em ory for inte rn al (generated
item s) than for exter nal events (read item s); an d E ich, M acau lay, an d Ryan (1994) dem onstrated m ood-dependent m em ory in three studies w here subjects generated au tobiog rap hical even ts in respo nse to neutral nouns. N ull ® nd ings or failu res to replicate have
been reported by Isen et al. (1978); N asby an d Yando (1982); B artlett an d San trock (1979);
Bartlett, Burleson, an d S an trock (1982); Bower et al. (197 8, Studies 1 & 2 ); S chare et al.
(1984, Studies 1 & 2); Bow er et al. (1981, Study 3); Bow er an d M ayer (1985); Wetzler
(1985); H aag a (1989); an d Foa, M cN ally, an d M urdock (1989). To take one exam p le of
the preoccupation w ith null ® ndings in the literature, E llis an d A sh brook (1991) note that
only very limited evidence of state-dependent effects w as obtain ed by L eight an d E llis
(1981, Study 2), an d that in eight possible instances w here state depend enc y could have
been p roduced, the effect w as reliably evident in o nly one.
It seem s therefore, that insightful an alysis of the reaso ns for the positive results o n
m ood-dep end ent retrieval m ay be dif® cult to sup port w ith published studies alo ne. N otw ithstanding this, certain m etho dological consideratio ns have been described w hich are
pertin ent to research con cer ning m ood-state dependency. E llis an d A shbrook (199 1) state
that the m eth odological issues in m ood an d m em ory research can be cate gorized according to three topics: sub ject factors, em otional-state factors, an d factors related to the
co gn itive task. E llis an d A shbrook (1991) provid e a useful review of these issues. H ow ever, there ap pear to b e som e m ore fundam ental p roblem s that can be identi® ed by
reference to stu dies reporting ne gative ® nd ings. T hese problem s concer n the m ethodolog ical rigour of both the design an d th e conduct of these experiments.
T he ® rst p roblem concer ns th e m ood m an ipulation stage of experim entation. T hree of
the stu dies that have reporte d null ® ndin gs do not provide objective m easures of experim entally m anip ulated m ood, leaving open the possibility that su bjects m ay not have been
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292
KEN EA LY
in the ap propriate m o od state (sam e or different), an d that m ood w as not su ccessfully
m an ipulated (Bower et al., 1978; Isen et al., 1978; N asby & Yando, 1982). Futher m ore,
stu dies of m ood-state dependenc y in general have failed to specify a priori criteria th at
de® ne differen ces between m ood cond ition s. A failure to ® nd differen ces between the
co nditions undertaken in different m ood states m ight therefore simply b e the resu lt of an
insuf® cient difference between the m an ipulated m oods, or variance in th e m ood elicited
under a particular co ndition. E ich an d M etcalfe (1989) have noted that by imp osing a
stringent criterion, the odds of dem on strating m ood-depen den t m em ory w ou ld be
improved. A num ber of studies have utilized an hypnosis technique to induce m oo d
(B ow er, G illigan , & M onteiro, 1981; B ow er & M ayer, 1985; B ow er et al., 1978 ). T he
lim itations of the hypnosis techn iqu e have been w ell docum ente d an d include the effects
of experimenter bias an d dem an d characteristics as w ell as selectiveness in subject populatio n (Bower & M ayer, 1991; G oodw in & W illiam s, 1982; H asher, Rose, Zacks, San ft, &
D oren , 1985; N asby & Yando, 1982). Indeed, it is possible that counter-dem an d m ay
account for som e of the observ ed ® n ding s using this technique, w here the experim enter
inadv ertently presen ts subjects w ith a ``d em an d not to produce dem an d effects’ ’ (Polivy &
D oyle, 1980). W ith these criticism s in m ind, Bower (1 981) has repeated certain experim ents using hap py or sad m usic in the backg round as a m ore unob tru sive for m of m ood
m an ipulation. A lthough noted in Bower (1981), the d ata from these m usic m ood induction experim ents are not reported or referenced. O ther studies of m ood-state± dependen cy have used the Velten technique (as described later on) to induce elated , depressed , or
neutral m ood states (Velten, 1968), bu t they hav e only provided o ne m ood g roup for
co m parison w ith a neutral g roup (e.g. Schare et al., 1984; L eight & E llis, 1981). T he
inclusion of a second, m ore d istinct m ood g roup m ight have per m itted state-dependent
effects to em erge.
A m ore m ajor problem w ith these stud ies how ever, is the possible confounding of
en coding an d retrieval. First, few studies repor t m easures of the level of initial lear ning,
an d they d o not ap pear to have controlled for the fact th at som e subjects m ay learn less
than o thers initially. W hen initial lear ning is not m easured objectively, there is no w ay
to separate the effect of m ood on lea rning from the effect of m ood on retrieva l; the
co nfounding of encoding an d retrieval in m any studies is a serious ¯ aw. Seco ndly,
su bjects in o ne g rou p lear ning less initially than subjects in an other group m ay lead
to the asym m etrical dissociations at recall that have been reported in a num b er of
stu dies, w here state dependency has only b een o bserved for positive m ood states
(B artlett et al., 1982; Bartlett & S an trock, 1979; M ecklenbrau ker & H ager, 1984), a
possible inference b ein g that there w as less initial lear ning in the neg ative m ood-states.
Further sup port for th is con clusion is provid ed by L eight an d E llis (1981) w ho ob served
an asym m etrical m ood-state± dep endent effect using the Velten m ood induction pro cedure. T hey report that the initial lear ning scores of depressed an d neutr al-m ood subjects differed signi® can tly, w ith depressed subjects lear nin g less than neutral-m ood
su bjects. In a pilot study we investigated the effects of alcohol on state-dependent
retrieval (K enealy, 1982). A lcohol affected rate of lear ning w ith subjects in the alcohol
g roup lear ning less in Trial 1 an d 2 than sober subjects. In E xperim ent 1a reported
here, the sam e patter n w as ob served w ith m ood affecting rate of learn ing. O n Trial 1,
elated subjects lear nt signi® can tly m ore (m ean = 12.01) th an depressed subjects (m ean
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M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
293
= 6.50); in further trials the effects of m ood did not ap pear to be linearly related to
rates of lear ning. D esign ing experiments to ensu re equivalence of in itial lear ning by all
su bjects ap pears to be an im portant factor in dem onstrating sym m etrical state-dependen t lear ning, a point noted by O verto n in 1974 but largely ig nored by contem porary
ex perimentalists in this area. It m ay b e that m any experiments can not be discoun ted o n
these g rounds (e.g. B ow er, personal com m unication 1994); how ever, data o n the rate an d
eq uivalen ce of lear ning have not alw ays been reported, so th e problem can not be entirely
dism issed.
Bow er et al. (1978) ap pear to have provided the clearest dem o nstration of m oodstate± dependent effects, although the phenom enon w as observed o nly under the
en han ced interference of two-list co nditions. Blaney (1986) notes that eviden ce o n
this point is also m ix ed. It is claim ed that m ood-state± dependent ® ndings w ith interference d esigns have been dif® cult to rep licate (Bow er & M ayer, 1985; Wetzler, 1985),
althou gh these attem pts ap pear to have been m odi® ed replications. Blaney (1986) conclu ded that ``E ven this effect, w hen evident, m ight be obtainable o nly w hen exposure
an d recall m oo ds are induced by procedures that are som ew hat sim ilar to o ne an other’ ’
(p. 231). H aag a (1989) pointed out that w hen the m ood induction procedure is the sam e
at lear ning an d recall, there is no w ay to separate the effect of m o od sim ilarity at
lear ning an d recall from th at of induction procedure similarity. H ow ever, in an experim ent using d ifferent induction techniques (th e Velten technique an d an au tobiog rap hical recollection procedure), H aag a con cluded that similarity of m ood indu ction
procedures did not affect recall. N onetheless, m ood-state± dependent retention w as
not dem onstrated.
T he purpose o f this article is not to present a detailed review of the m ood-state±
dependent literature; ad equate accounts m ay be found elsew h ere (e.g. Blaney, 1986;
Peeters & d’ Ydew alle, 1987). H ow ever, it does seem that a num ber of important factors
an d seriou s ¯ aw s in experim ental design have contributed to the equivocal nature of the
® ndings concer nin g m ood-state dependenc y. In sum m ary, all of the studies previously
m entioned have one or m ore of the following problem s: designs that have co nfou nded
en coding an d retrieval by not m easuring (or reporting) initial lear ning scores; a lack of
objective m easures of m ood m an ipulation; the use of the sam e m etho d of m ood ind uction
at encoding an d retrieval, so co nfounding the effect of m ood an d the effect of the
induction procedure. T he evid ence available at present, therefore, does not allow de® nitive statem ents to be m ad e concer ning the generality an d reliability of m ood-state± dependen t retention. A lthough other factors such as those m entioned by E llis an d A shbrook
(1991) m ay clearly be im portant, exp erimental evidence that tak es account of the m ore
fundam ental problem s of d esign inhere nt in the p revious w ork need s to b e provided. T he
ex periments reported here were designed w ith th ese issues in m ind . Inv estigatio n of the
issues required various levels of control an d involved proceed ing throu gh a num ber of
stages of research. In all experim ents, objective m easures of m ood ind uction were provid ed; the ® rst two experiments (1a an d 1b) ad dressed the problem of con fou ndin g
en coding an d retrieval; th e third experim ent (1c) ad dressed the issue of co nfou nding
the effects of m ood an d o f the induction procedure; an d the fourth an d ® fth experiments
investigated som e of the interesting question s co ncer ning the nature of retrieval cues in
m ood-state± dependent retrieval.
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KEN EA LY
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E X P E R IM E N T S 1 A , 1 B , 1 C
K ihlstrom (1991) points out that the hypoth esis of m ood-state± dep en dent retrieval is
based on an an alog y w ith state-d ependent m em ory produced by phar m acological substances such as alco hol, barb iturates, am ph etam ines, an d m arijuan a. Som e of th e m ethodological problem s associated w ith previous state-d ependent experim ents have been
noted by O verto n (1974)Ð in particu lar, the issue of asym m etrical or o ne-w ay dissociatio n
of lear ning. In a review of the effects of alcoh ol on m em ory, Ryback (1971) noted th at such
state d ependency tends to be asym m etricalÐ that is, subjects w ho lear n in an intoxicated
state an d recall in a sober state forget m ore than sub jects w ho lear n in a sober state an d
recall in an intoxicated state. O verto n (1966) also observed this asym m etrical dissociatio n
of lear ning. Berger an d Stein (1969) proposed a neural m odel to explain the observatio n
that su bjects going from a drug to a non -drug state forget m ore than do subjects going
from a non -drug to a drug state (refer red to as ``o ne-w ay dissociation of lear ning’ ’ ).
W hether the explanatio n of one-w ay dissociation lies in the structure of the brain or in
the design of the test situatio n (or both) is open to question. It m ay b e that su bjects
``taught’ ’ under the in¯ uence of alcohol have lear ned less at the end of the ``training’ ’ than
the groups n ot taught under alcohol. O verton (1974), in a review of the experimental
m ethods used to study state-dep end ent lear ning, has poin ted out that w e m ust be sure
that an equivalen t am ount of learn ing occurs in all conditions before we claim that the
co ndition ``cau ses’ ’ am nesia an d not sim ply poorer lear ning initially. By an alogy, it is
en tirely possible th at d ifferent m ood states m ay similarly lead to poorer lear ning initially,
an d it m ay be that individual differences w ill also contribute to the variance in initial
lear ning. In any case, w ithout an ob jective m easure of initial lear ning, the effects of m ood
on m em ory at encoding w ill be confounded w ith the effects of m ood at retrieval. Reference
to the p roblem s encountered in d ru g-induced-state± dependent experim en ts (O verto n,
1974 ) suggests the n eed for an im proved design that takes into account the initial lear ning
of all sub jects.
M e th o d
T h e d esign , m aterials, an d pr oced u res for E xp erim ents 1a, 1b, 1c are p resen ted together.
D e sig n
In each exp erim en t a 2 3 4 expe rim en tal d esign w as em p loyed . In E xp erim en t 1a, o n D ay 1, h alf
the sub jects lear n ed th e m em ory task after th e elation versio n of th e Velten m ood indu ction p ro ced u re [G ro up s 1 (E E ) & 2 (E D )], an d h alf th e su bjects lear n ed th e task after the d ep ressio n ver sio n
[G ro u p s 3 (D D ) & 4 (D E )]. O n D ay 2, h alf the su bjects recalled after ind u ction of th e sam e m ood
w ith th e Velten p roc edu re [G ro up s 1 (E E ) & 3 (D D ))], and h alf th e su bjects recalled after ind u ctio n
of a d ifferen t m ood [G ro u p s 2 (E D ) & 4 (D E )]. In E xp erim ents 1b an d 1c, th e d esign w as iden tical,
except th at h ap p y an d sad m usic m ood ind u ction s w ere u sed [G ro up 1 (H H ); G ro u p 2 (H S ); G ro up 3
(S S); G rou p 4 (S H )].
It w as h yp oth esiz ed th at if sim ilarity of m ood state at lear n ing an d recall facilitates rem em berin g,
su bjects lear n ing an d recalling in an ind u ced elated /ha pp y m ood and su bjects lear n ing an d recalling
in an ind u ced dep resse d /sad m ood wo u ld h ave sign i® can tly lower (less) d ecrem en ts in recall th an
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
295
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su bjects recalling in a d ifferen t ind uced m ood fro m th at in w h ich th ey lear n ed th e m aterial. Form ulating th e m ood -sta te± d ep en d ent retrieval h ypo th esis so as to requ ire a d irect test of th e differen ce in th e decrem en t in recall betw een th e sa m e-m ood an d th e ch an ged-m ood g ro u p s allows for th e
p ossib ility tha t th ere m ay b e sign i® can t sh ifts even for th ose g ro up s lear n ing an d recalling in th e
sam e m ood state becau se of th e u sua l d ecrem en ts th at occu r betw ee n sessio n s (see Wester m an n &
H ager, 1983).
In add itio n, p rov ided a con d ition of equ ivale nce of initial lear n ing w as m et by all su bjects (elated /
h ap py an d de pre sse d /sad ), it w as expected tha t th e state disso ciation d ecrem en ts w ou ld be sym m etrical in na tu reÐ th at is, th e nu m ber of item s forg otten w ould be abou t th e sam e, w h eth er su bjects
lear n ed in an ind u ce d elated m ood an d recalled in an indu ced d epre sse d m ood or lear n ed in an
ind u ced dep resse d m ood an d recalled in an ind uced elated m ood .
M o o d In d u c t i o n s
Velten M ood I nduction P rocedure. A s a nu m ber of stu d ies h ave u sed th e Velten m ood ind u ctio n
p roc edu re to investig ate th e effects of m ood on m em ory, a m od i® ed ver sio n of th e Velten p ro ced u re
w as u sed in th e initial E xp erim ent 1a. T h e m oo d ind u ction p ro ced u res were th e sa m e as th ose u sed
by Teasd ale an d Taylor (1981), a m od i® ed ver sio n of tho se u sed by Velten (1968). For each m ood
ind u ctio n, su bjects read 12 card s bearin g typ ed self-referen t statem en ts. For the elation ind uction ,
the statem en ts u sed w ere: I feel pretty good right now; I feel ha ppy ; I feel cheerful, con® dent; I ca n think
quickly a nd clea rly right now; R ight now, I feel very contented; R ight now, I feel like smiling; I feel a lert,
ha ppy a nd full of energy; I ha ve a feeling of lightness a nd joy; I rea lly like this lighthea rted feeling; I ca n
feel a smile on my fa ce; I feel so good I a lmost feel like la ughing, and I t feels grea t to be a liv e! For th e
d epre ssio n m ood ind uctio n , th e statem ents u sed w ere: I feel unha ppy ; I feel sa d a nd blue; I feel fed up;
I just feel dra ined of energy, worn out; I feel pretty low; Things seem futile, pointless; I feel hopeless; I feel
down-hea rted a nd misera ble; I feel so tired a nd gloomy tha t I would ra ther just sit tha n do a ny thing; I feel
hea vy a nd sluggish; I t seems such a n effort to do much, an d I ’ m fed up with it a ll.
M usic M ood I nduction P rocedure. In E xp erim en ts 1b an d 1c, a m u sic m ood ind u ctio n p ro ced u re
iden tical to th at rep or ted by K enealy (1988) w as use d . M u sic selectio ns w ere record ed o n tap e an d
con sis ted of a ha pp y selection fr om Coppelia (``M azu rka ’ ’ ) by D elibes, an d a sad selection , A da gio in
G minor, by A lb inon i. T h ese tw o selection s ha d be en sho w n differen tially to affect self-rep orted
m ood an d beh aviou r in th e d esired w ay by p reviou s research, an d th e m usic affected sub jects’ m ood s
in th e ab se nce of ins tr u ction s to try to cha ng e th eir m ood s (K en ealy, 1988, Par ro tt & S abini, 1990).
M ood M ea sures. A s a m eas ure of the effect of th e m ood indu ction p ro ce du res, su bje cts w ere
ask ed to rate th eir m ood on thre e 0± 100-line scales. E ach scale w as 10 cm lo ng w ith th e 0 en d labelled
I do not feel a t a ll X , an d the 100 en d labe lled I feel extremely X . O n th e th ree scales ``X ’ ’ w as H a ppy,
A nx ious, an d Despondent in E xp erim en t 1a, an d H a ppy, A nx ious, an d S a d in E xp erim en ts 1b an d 1c.
A T TH I S M O M E N T w as typ ed at th e top of each sh eet to ind icate th at it w as instan tan eou s m ood
that w as to be r ated . T h ese m eau res h ave been u sed in p reviou s stu d ie s to m easu re th e effect of
m ood -in d u ction p ro ced ure s (Teasd ale & Fog arty, 1979; Teasda le & Taylor, 1981; Teasd ale, Taylor, &
Fog ar ty, 19 80).
M ood A ccepta nce C riterion. Becau se the interest of th ese e xp erim en ts w as in ind u cing tw o
d ifferen t m ood states a criterion w as ch osen , before th e exp erim en ts beg an , to d e® ne an ad equ ate
d ifferen ce in m ood betw een th e tw o m ood con d ition s. T h is w as th at th ere sho u ld be at least a 20 p oint diffe ren ce betw een th e ha pp iness an d d esp on den c y r atings im m ed iately after m ood ind u ctio n
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KEN EA LY
on each d ay. T h is criterion w as u sed by Teasd ale an d Fog ar ty (1979), Teasd ale, Taylor, an d Fogarty
(1980), an d Teasd ale an d Taylor (1981) to d e® n e an ad equa te d ifferen ce in m ood betw een tw o m ood
con d ition s. In add ition , for su bjects in the d ifferen t m oo d gro u p s (E D and D E ) the criterion w as th at
there sh ou ld be at least a 20-p oint d ifferen ce be tw een th e h ap p iness (or desp on d en cy) ratin g o n D ay
1 an d th e h ap p iness (or desp on d en cy) r ating on D ay 2.
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M e m o ry T a sk
A m em ory task th at cou ld be u sed in a con tro lled labor atory situ atio n w as co n stru cted .
S ub jects w ere ask ed to m em oriz e a sim p le geogr ap h ical m ap, visu ally d isp layed, tog eth er w ith
an au ditorally p resen ted 22-item set of d irection s con cer n ing a p ar ticu lar ro u te. T h e s eries of
d irection s rep resented affectively n eu tr al m aterial th at w ou ld avoid con fou n d ing state-d ep end en t
retrieval w ith m ood co n gr uen cy explan atio n s of th e ® n d ings. S u bjects w ere p resen ted w ith a
sty lized ``m ap’ ’ th at sh ow ed a ro u te com pr ised of 11 se gm ents. T h e en ds of each segm en t
w ere asso ciate d w ith a land m ark (p u b, library ), w h ich w as ind icated by a sim p le line d r aw ing
on th e m ap an d w as also labelled . T he directio n of tu r n of th e ro u te w as also sh ow n at th e en d of each
segm en t. T h e ``m ap ’ ’ w as p resent th rou gh ou t a d escrip tion of th e ro u te, w hich w as read to th e
su bject (``P ro ceed to th e su per m ark et; tu r n left ag ain; con tinue to th e sp or ts cen tre; . . .’ ’ ). T h e
``m ap ’ ’ w as th en rem oved , an d the sub jects were as ked to p rov ide a free recall of th e 22 elem en ts of
the ro u te (landm ark s an d d irection s of tu r n ). T h e resu lting score w as th e nu m ber of elem en ts
recalled , irresp ective of ord er. T h e task w as design ed to p rov ide a n atu ra l an alogu e to th at of
rem em berin g an d giving d irection s for a rou te th ro ug h a city.
I nitia l Lea rning C riterion. A score of on e w as given for each item cor re ctly lear n ed . In ord er to
en sure equ ivalen ce of initial lear n ing, an arb itrary criterion of at least 18 item s cor rect w as ad op ted as
a lear n ing criterio n . E ach su bject w as allowed 4 lear n ing trials to reach th is criterion . If after 4 trials
the criterion w as n ot attained , th en th e largest nu m be r cor re ct in any on e trial wo u ld be taken as th e
su bject’ s p erfo r m anc e score.
P rocedures. O n D ay 1, th e m ood scales were sh ow n and exp lained to su bje cts. T he ove rall
p roc edu re w as th en sum m arized , an d su bjects w ere told tha t th e exp e rim en t w as co n cer ned w ith
m ood an d le ar n ing sty le s. For th e Velten m ood ind u ction p ro ced u re, th e im p ortan ce of tr ying to
becom e fu lly involved in th e m ood ind u ction pro ced u re w as em p h asized . S u bjects w ere told th ey
sh ou ld try as h ard as p os sible to feel th e m ood su ggested by th e s tatem en ts; it w as stated th at th is
m ight take so m e effor t an d th at it w as a cru cial p art of th e exp erim e nt. In E xp erim en t 1a, su bjects
w ere th en ask ed to read th e s tatem en ts silen tly, at th eir ow n spe ed , retur nin g to th e be ginn ing of th e
p ile if they reach ed th e en d. T hey w ere told to sto p read ing after 5 m in.
For th e m usic m ood indu ctio n p ro ced u re, su bjects w ere escorted into a sou n d -p ro of ro om an d
seated com fortably. T h e exp erim enter th en m ad e an excu se of h aving so m eth ing u rg en t to attend to
an d left the ro om , leaving either th e hap p y or th e sad m usic p laying qu ietly in the backg rou n d . T h e
experim en ter retu r n ed to th e ro om after app rox im ately 5± 8 m in.
A ll su bjects w ere th en ask ed to m em oriz e th e geog rap h ical m ap, visu ally d isp layed, toge th er w ith
the au ditorally pre sen ted 22-item set of directio n s con cer n ing a p ar ticu lar ro ute. T h e follow ing
sta nd ard set of instru ctio ns w as given to each sub ject:
``H ere is a picture of a ma p. I would like you to look a t the ma p while I rea d you a series of
instr uctions which will ena ble you to get from one pla ce to a nother on the ma p. I will then ta ke a wa y
the ma p, a nd a sk you to reca ll a s ma ny of the instructions a s you ca n remember.’ ’
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
297
In E xp erim ent 1a, su bjects rated th eir m oo d o n th e th ree scales at th e following p oints in th e
experim en t:
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1. im m ediate ly after th e 5-m in m ood in ductio n;
2. afte r th e ® rst lear ning trial, in order to verify th at th e subject’ s m ood state had not
chan ged sign i® cantly.
In E xp erim en ts 1b an d 1c, su bjects r ated th eir m ood im m ed iately follow ing th e m usic m ood ind u ction . O n e m easu re of the effect of th e m oo d ind u ction p roced u re w as con sid ered su f® cien t, becau se
the pro ced u re h ad been sh ow n p reviou sly to affect m ood sign i® can tly (K en ealy, 1988).
Su bjects were th en th an ked for their h elp an d ask ed to retu r n at th e sam e tim e o n th e follow ing
d ay, on th e pre text of h aving to com p lete a few m ore lear nin g task s. O n D ay 2 (24 h our s later), after
the app ro p riate m ood ind uction , su bjects rated their m ood on th e thre e scales an d w ere then ask ed to
recall as m any of the instru ctio ns tha t accom p anied th e m ap as th ey cou ld re m em ber from the da y
before, w ithout again refer rin g to th e m ap. T h e n um ber of item s cor rectly n am ed by each su bject w as
taken as their recall score.
E X P E R IM E N T 1 A
M e th o d
T h irty-tw o ® r st- and secon d- year u n derg ra du ate stu d entsÐ 1 4 m ales an d 18 fem alesÐ w ere
recru ited . T he age of th e 24 sub jects m eeting the accep tan ce criterion for th e stud y ran ged from
19 to 39 years, w ith a m ean age of 24.8 year s.
R e s u lts
M ood M ea sures. E ight subjects failed to reach the m ood acceptance criterio n. Table 1
sh ow s the effect of the elatio n an d depression m ood inductions as rated by subjects on the
three 0± 100 m ood scales. T he results show n are the m ean rating s on the three scales from
the two occasions of m easurem ent following m ood induction on D ay 1 an d D ay 2.
Subjects in the sam e m ood groups (E E & D D ) showed n o signi® can t d ifferences in
ratin gs on the three m ood scales, co n® r m ing that they had lear ned (on D ay 1) an d
recalled (on D ay 2) the m em ory task in the sam e m ood state, w hich is crucial to the
ex periment. S ubjects receiving different m ood inductions on D ay 1 an d D ay 2 (E D &
D E ) showed signi® can t differences in ratings o n the ``hap piness’ ’ an d ``despondency’ ’
m ood scales, co n® r m ing that subjects recalling on D ay 2 w ere in a different m oo d state
from the one in w hich they lear ned the m em ory task o n D ay 1. T here were no signi® can t
differences b etween subjects’ ratings o n the an xiety scale on D ay 1 an d D ay 2 in an y of
the four g roups. T he p atter n of results w ith respect to m ood m an ipulation w as id entical
in E xp eriments 1a, 1b, an d 1c, as show n in Table 1.
M ood a nd M emory. M ood induction did not differentially affect lear ning perfor m an ce on D ay 1: there w as no signi® can t difference b etween the lear ning scores of
depressed (m ean = 18.6, S D = 1.16) an d elated (m ean = 19.4, S D = 1.31) subjects o n
D ay 1, t (22) = 1.65, p > .05. T hus, the condition of equivalence of initial learn ing by
su bjects in the different m ood g rou ps had been m et. M ood induction did not differen-
298
KEN EA LY
TA BLE 1
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E f fe c ts o f H a p p y a n d S a d M o o d In d u c ti o n s
Experiment 1a
Experiment 1b
Experiment 1c
M ood I nduction
M ood I nduction
M ood I nduction
Mea sure*
Da y 1
Da y 2
Da y 1
Da y 2
Da y 1
Da y 2
Group 1
Hap piness
Anxiety
Sad ness
Elatio n
60 .5
21 .7
16 .2
E latio n
59.8 ns
21.3 ns
15.8 ns
Hap py
67.3
12.7
12.0
H ap py
66.6 ns
11.3 ns
11.9 ns
Happ y
63.3
18.5
14.9
H ap py
64.5 ns
16.6 ns
15.1 ns
Group 2
Hap piness
Anxiety
Sad ness
Elatio n
61 .0
15 .0
24 .7
Depression
29 .5 **
11.8 ns
55 .7 **
Hap py
64.7
10.4
16.9
Sad
16.0 **
14.0 ns
61.8 **
Happ y
63.5
12.3
19.4
S ad
19.4 **
14.1 ns
59.2 **
Group 3
Hap piness
Anxiety
Sad ness
D epression
29 .2
9.8
54 .2
Depression
22.7 ns
10.7 ns
57.3 ns
S ad
19.3
11.1
67.9
Sad
18.3 ns
9.7 ns
65.6 ns
Sad
24.2
9.4
62.9
S ad
21.0 ns
10.1 ns
62.7 ns
Group 4
Hap piness
Anxiety
Sad ness
D epression
28 .2
21 .3
52 .0
E latio n
72 .3 **
15.2 ns
19 .2 **
S ad
19.7
10.7
60.1
H ap py
59.9 **
10.0 ns
9.7 **
Sad
25.0
15.4
58.2
H ap py
64.6 **
14.1 ns
15.8 **
* M ean of subjects’ ratin gs o n 0± 100 scales.
** S ign i® can t diffe rence betwen m ood ratings on Day 1 an d Day 2, p < .001.
tially affect overall recall prefor m an ce o n D ay 2 either: there w as no signi® can t difference
between recall scores of depressed (m ean = 15 .3, S D = 3.86) an d elated (m ean = 15.5,
S D = 4.03) subjects o n D ay 2, t(22) = 0.10, p > 0.05.
H owever, an independen t t test an alysis show ed that the decrem ent in recall of the
sam e-state groups (E E + D D ), m ean = 0.42 item s, com pared to the decrem ent in recall of
the ch an ged-state groups (E D + D E ), m ean = 6.8 item s, w as signi® can tly different. T he
chan ged-state groups forgot signi® can tly m ore items than did the sam e-state groups, t(22) =
9.9 79, p < .001. Table 2 show s the lear ning an d recall scores from the four g roups of
su bjects, togeth er w ith the m ean decrem ents in recall for the sam e-state g roups an d the
ch an ged-state g roups.
Further m ore, the dissociatio n decrem ents were about the sam e, w heth er the tran sfer
w as from elation indu ction on D ay 1 to d epression indu ction on D ay 2 [G rou p 2 (E D ):
m ean decrem ent = 7.2, S D = 2.14], or from depressio n induction o n D ay 1 to elatio n
induction on D ay 2 [G rou p 4 (D E ): m ean d ecrem ent = 6.3, S D = 2.26]. T h ere w as no
signi® can t difference in the num b er of item s forgotten by sub jects in these two groups,
t(10) = 0.62, p > .05.
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
299
TA BLE 2
M e a n L e a r n in g a n d R e ca ll S co r e s
Experiment 1a
Da y 1
Group
Mea n
EE
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M ea n
SD
1.64
18 .8
19.0
1.47
1.7 8
18.5
1.03
0.82
12.2
12.0
2.6 4
1.7 9
SD
19.5
DD
ED
DE
Da y 2
1.38
19.3
18.3
Experiment 1b
Da y 1
Group
HH
SS
HS
SH
E xperiment 1c
Da y 2
Da y 1
Da y 2
M ea n
SD
M ea n
SD
M ea n
SD
Mea n
SD
19.1
18.4
18.1
18.5
1.07
1.51
0.69
0.98
18.1
17.7
10.9
11.3
0.89
1.11
1.21
1.60
19.7
18.5
18.8
18.4
1.25
1.18
1.03
0.97
18.9
17.7
11.5
11.5
1.37
1.16
2.32
1.43
D is cu s s io n
T he results indicated a m ood-state± dependent retrieval effect. Subjects w ho learn ed an d
recalled in the sam e m ood forgot sign i® can tly fewer item s than did subjects w ho lear ned
an d recalled in a different m ood; chan ging su bjects’ m ood state at recall produced signi® can tly g reater decrem ents in recall. In ad dition, the num b er of item s ``fo rgotten’ ’ by
su bjects w as about the sam e, w hether tran sfer w as from elatio n induction on D ay 1 to
depression induction on D ay 2 or from depression induction o n D ay 1 to elation induction on D ay 2, indicating a sym m etrical m ood-state± d ependent retrieval effect.
W ith respect to th e m ood inductions, read ing self-referent statem ents su ccessfully
induced elation an d depression in subjects. M ood induction did not differentially affect
su bjects’ ability to lear n the m em ory task on D ay 1. D epressed subjects did n ot requ ire
m ore trials overall to ach ieve the lear nin g score criterio n, as m ight have been expected
from th e ® ndings of L eight an d E llis (1981); the m ean num ber of trials to reach the
criterion w as 3.9 for depression-indu ction subjects an d 3.8 for elation -induction su bjects;
how ever, o n Trial 1 elated subjects lear ned sig ni® can tly m ore (m ean = 12 .01) th an did
depressed subjects [(m ean = 6.50), t(22) = 2.92, p < .01]. M ood induction w as show n not
to have differen tially affected recall perfor m an ce on D ay 2 either, indicating th at the
observed state-dependent retrieval effect w as due to similarity or dissim ilarity of su bjects’
m ood states at th e time of learn ing an d recall and not to the m ood-induction procedures
affecting sub jects’ ability to perfor m during the learn ing an d recall testing sessio ns. T he
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300
KEN EA LY
m em ory task proved relatively easy to score, interscorer reliability show ed 99.4% ag reem ent on item s, an d forgetting an d rem em bering of item s w as rand om ly distributed
throughout the task, ap art from a trend for all subjects to rem em ber the ® rst an d last
item s in the task.
It ap pears therefo re in this initial experiment that a design that ensured equivalence of
initial lear ning an d exam ined decrem en ts in recall b etween lear ning an d recall sessions
su ccessfully facilitated the d em onstratio n of m ood-state± dependent re trieval.
It is im portant to investigate how lear ning an d m em ory are affected by the relatively
co m m o n occur rence of tr an sient ¯ uctuatio ns in m oo d, an d the Velten m ood ind uction
procedure allow s for such investigatio ns. H ow ever, a num ber of au thors have pointed
out the disadv an tages of th is procedure. C lark (1983) has noted that a m ajor problem
w ith th e Velten procedure is that 30% to 50% of subjects fail to respo nd to it. In the
ex periment reported here, 25% (n = 8) of subjects failed to respo nd to the procedure
an d did not m eet th e criterion used to de® ne an ad eq uate difference between the m ood
states of elation an d depressio n. In ad dition, the Velten procedure places a stro ng
em phasis on sub jects tryin g hard to get into the desired m ood , an d it is possible that
som e subjects m ay have reported feeling elated or depressed after th e induction procedu res, w hen in fact they have not felt the m oods suggested by the statem ents. A
num ber of au thors have ad dressed the issu e of the co ntribution of dem an d characteristics to the Velten m ood in duction p roced ure (e.g. B uchw ald, Strack & C oyn e, 1981;
Polivy & D oyle, 1980). K enealy (1986) reviewed 46 published experim ents that had
used the Velten p roced ure an d concluded that the ® ndings relatin g to the p rocedure’ s
effectiveness w ere equivocal, as w ere assessm ents of the co ntribution of dem an d
ch aracteristics to the procedure.
Taking these factors into account, it therefo re seem ed adv isable, in order to co ntinue
this line of research, to use an alter native m ethod of m ood induction. T he use of m usic
to induce m ood states ap peared to b e a suitable alter native to w hich subjects m ight
respond m ore easily, an d it has been used in several lab oratory experim ents investigating
the effect of m ood on m em ory (Bower & M ayer, 1991; C lark, 1983; C lark & Teasdale,
1985 ; Parrott & Sabini, 1990). T hus, a m usical procedure w as used as a m ore subtle
m ethod of m ood in duction to investigate the gen erality an d reliab ility of m ood-state±
dependent retrieval.
E X P E R IM E N T 1 B
T his exp erim ent attem pted to rep licate the m ood-state± depen den t retrieval effect
observed in E xperim en t 1a. T he sam e design an d m em ory task were em ployed, but a
m usic m ood-induction procedure (K enealy, 1988) w as used to induce ``hap py’ ’ an d ``sad ’ ’
m oods. T he purpose o f the experiment w as to investigate the generality an d reliability of
the m ood-state± dependen t retrieval effect, using a d ifferent m ethod of m ood induction. It
w as felt th at rep lication of th e previous ® nding w as necessary in ord er to establish
w hether the phenom eno n of m ood-state± dependent retrieval could be dem onstrated
using different m ethods o f m ood in duction .
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
301
M e th o d
T h irty ® rst- an d secon d -year fem ale u n d erg r ad u ate stu d en ts w ere recru ited. T he age of the 28
su bjects m eeting th e accep tan ce criterion for th e stu d y ra ng ed fro m 19 to 26 years, w ith a m ean
age of 22.9 year s. A stereo casse tte d eck con n ected to tw o free-stan d ing sp eaker s, w as u sed to p lay
two selectio ns of m u sic for th e ``ha pp y’ ’ and ``sad ’ ’ m ood ind u ction s, as alread y d escribe d.
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R e s u lts
M ood a nd M emory. O ne sub ject failed to reach the m ood acceptance criterion, an d
one subject failed to retur n o n D ay 2. M ood ind uction did not differentially affect
lear ning perfor m an ce on D ay 1 ; there w as no signi® can t differe nce between the lear ning
scores of sad (m ean = 18.6, S D = 1.22) an d hap py (m ean = 18.8, S D = 1.01) subjects o n
D ay 1, t(26) = 0.34, p > .05. M ood in du ction d id not differentially affect recall perfor m an ce o n D ay 2 eith er; th ere w as no signi® can t difference b etween recall scores of sad
(m ean = 14.3, S D = 3.73) an d hap py (m ean = 14.7, S D = 3.68) subjects on D ay 2, t(26) =
0.3 0, p > .05.
Independent t test an alysis showed that the decrem ent in recall of the sam e state groups
(H H + S S), m ean = 0.86 item s, com pared to the decrem ent in recall of the chan ged
state g roups (H S + SH ), m ean = 7.29 item s, w as signi® can tly different. T he chan gedstate g roups forgot sign i® can tly m ore item s than did the sam e-state g roups, t(26) =
12.19, p < .001. Table 2 show s the lear ning an d recall scores from the four g roups of
su bjects, togeth er w ith the m ean decrem ents in recall for the sam e-state g roups an d the
ch an ged-state g roups.
A s in the p revious experim ent, th e dissociation decrem ents were about the sam e
w hether the tran sfer w as from hap py induction on D ay 1 to sad induction o n D ay 2
(g rou p 2 : H S; m ean decrem ent = 7.3, S D = 1.60), or from sad induction o n D ay 1 to
hap py induction o n D ay 2 (g roup 4: S H ; m ean decrem ent = 7.6, S D = 1.80). T here w as
no signi® can t difference in the num b er of item s forgotten by su bjects in these two groups,
t(12) = 0.19, p > .05.
D is cu s s io n
T he sym m etrical-m ood-state± dependent retrieval effect ob served in the previous
ex periment w as replicated using a different m ethod of m ood induction. Sub jects lear ning
an d recalling on D ay 2 in d ifferent m ood states had signi® can tly greater decrem ents in
recall th an did subjects lear ning an d recalling in th e sam e m ood states. A ll subjects except
one w ere affected by the procedure. T he m usic procedure proved to be a m ore subtle
m ethod of m ood induction an d easier to ad m in ister than th e m odi® ed Velten (1 968)
technique.
T he laboratory situation provid es a very different context for the individual from the
co ntexts experienced in everyday life, w hich are rarely identical on any two occasio ns.
Indeed, it is possible that the effects observed here w ere d ue to the laborato ry pro cedures of m ood induction rather than to the m ood effects them selves. D em an d ch aracteristics are inherent in an y laboratory experim ent, an d although explicit dem an ds
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302
KEN EA LY
can be controlled to an extent, there still rem ain im plicit dem and s in such situatio ns to
w hich subjects m ay respon d (for a detailed discussio n of dem an d characteristics see
K enealy, 1988). T he two selections of m usic used in the procedure d escribed here had
been validated previously (Kenealy, 1988) usin g a sim ilar procedure to that described by
Velten (1968), w ith the ad dition of two counter-d em an d g roups identical to those of
Polivy an d D oyle (1980). Polivy an d D oyle hypothesized th at if dem an d characteristics
are responsible for the m ood effects found, subjects in the counter-dem an d groups
would show a reversed em otion effect in the opposite direction. K enealy (1988) foun d
no reversed em otional effects w ith the procedure used in E xperim ents 1a an d 1b.
H owever, in these two experim ents th ere w as no w ay to separate the effect of m ood
sim ilarity at learn ing an d recall from that of in duction procedure sim ilarity (H aag a,
1989 ). A s a solution to the problem of w hether the m ood-state± dependent effects
observed in the p revious experim ents w ere attributable to the procedu res used or to
the m oods them selves, Experim ent 1c attem pted to dem onstrate m ood-state± dependent
retrieval using different m ethods of m ood induction at lear ning an d recall; results m ight
then be m ore convincingly inter preted in ter m s of the effects of m ood rather than of
procedure.
E X P E R IM E N T 1 C
T he issue of con foun din g the effects of m ood an d o f the induction procedure w as
add ressed by using the Velten m ood-indu ction procedure an d the m usic m ood-ind uction
procedure described previously.
M e th o d
T h e design , m em ory task , an d gen era l p ro cedu re were ide ntical to th ose u sed in E xp erim en ts 1a an d
1b. Su bjects received the Velten m oo d-in d u ction p ro cedu re d u ring lear n ing o n D ay 1 an d th e mu sic
m ood -in d u ction pr oc edu re d urin g recall o n D ay 2. Forty -tw o ® rst- an d secon d -year un d erg rad u ate
stu d en tsÐ 20 m ales an d 20 fem alesÐ w ere recr uited as su bjects. T he age of th e 40 su bjects w h o m et
the criterio n ran ged fro m 18 to 38 year s, w ith a m ean age of 22.6 year s.
R e s u lts
M ood a nd M emor y. Two subjects failed to reach the m ood acceptance criterio n.
T here w as a signi® can t difference between the lear ning scores of sad (m ean = 18.5,
S D = 1.05) an d hap py (m ean = 19.3, S D = 1.20) subjects on D ay 1, t(38) = 2.23, p < .05.
H owever, m oo d induction did not differentially affect recall perfor m anc e o n D ay 2Ð
there w as no signi® can t difference between recall scores of sad (m ean = 14.6, S D = 3.65)
an d hap py (m ean = 15.2, S D = 4.03) sub jects on D ay 2, t(38) = 0.49, p > .05.
T he decrem en t in recall of the sam e-state g roups (H H + S S), m ean = 0.80 item s, w as
signi® can tly less than the decrem ent of the chan ged-state groups (H S + SH ), m ean =
7.1 0 item s. T he chan ged -state g roups forgot signi® can tly m ore item s than d id the sam e-
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
303
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state g roups, t(38) = 14.18, p < .001. Table 2 show s the lear ning an d recall scores from
the four g roup s of subjects, together w ith the m ean decrem ents in recall for th e sam estate g rou ps an d the chan ged-state g rou ps.
A s in the p revious exp eriments, the dissociation d ecrem en ts were about the sam e
w hether the tran sfer w as from hap py induction on D ay 1 to sad induction o n D ay 2
(g rou p 2 : H S; m ean decrem ent = 7.8, S D = 1.89), or from sad induction o n D ay 1 to
hap py induction o n D ay 2 (g roup 4: S H ; m ean decrem ent = 6.9, S D = 1.66). T here w as
no signi® can t difference in the num b er of item s forgotten by su bjects in these two groups,
t(18) = 0.50, p > .05.
D is cu s s io n
T he m ood-state± d ependent hypothesis w as supported, w ith subjects in the chan gedm ood g roups forgetting signi® can tly m ore item s th an subjects in the sam e-m ood g rou ps.
T his effect w as dem onstrated w hen different m ood-in duction procedures w ere u sed at
lear ning an d recall; it therefore seem s m ore likely that the effects on m em ory are attributable to m oo d rather than to th e procedures used to induce m ood.
In the three experiments rep orted h ere, m ood-state± dependent retrieval has ap peared
to b e a reliable phenom eno n. In view of the previous literature in th is area, perhap s the
m ost interesting observation is n ot that the effect has been dem o nstrated, but w hy it has
been dem onstrate d so reliably. T he previous inconsistencies in the literature h ave been
discussed in the introduction, an d a nu m ber of problem s that m ay, at the very least, have
co ntrib uted to the inconsistent nature of ® ndings in this area w ere identi® ed. T he experim ents reported here w ere designed to ad dress these problem s. Speci® cally, objective
assessm ent of m oo d w ith an a priori criterion speci® ed to de® ne differences b etween
m ood conditions con® r m ed that subjects were in the ap pro priate m ood states. A ssessm ent
of m ood has been acknow ledged as necessary (E llis & A shb rook, 1 991) in order to
elim in ate the possibility that a failure to dem o nstrate m ood-state± dependen cy is due to
an insuf® cient difference between th e m an ipu lated m ood s, or variance in th e m oo d
elicited under a particular co nd ition . T he m ood-state± dependent effects observed in
the ® rst two experiments are open to the criticism that the use of the sam e m ethod of
m ood induction at encoding an d retrieval confounded the effect of m ood an d ind uction
procedure. E xperim ent 1c ad dressed this problem . It m ay be that the m em ory task w as a
critical variable in facilitating the state-dependent effect. E llis an d A shbrook (1988; 1 991)
argue that episodic m em ory tasks w ith less m ean ingfu l an d less structured m aterial are
m ore susceptible to m ood effects, although th ey believe that the results argue ag ainst an y
sim ple patter n of m em ory decrem ents across the b oard, reg ardless of the type of m em ory
task em ployed (E llis & A shbrook, 1991, p. 12).
It is clear throug h all this d iscussion that there is a critical m ethodological issue th at
previou s research ap pears to have failed to add ressÐ the issue of exp erimental designs
co nfounding encoding an d retrieval by not m easuring (or reporting) initial lear ning
scores. In th e experim en ts reported here, th e design ensured equivalence of initial lear ning by all g roups of su bjects, an d th e m ood-state± dependent retrieval hypothesis w as
for m ulated so as to requ ire a direct test of the difference in the decrem ent in recall
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KEN EA LY
between th e sam e-m ood an d the chan ged-m ood g roups. T his allowed for the possibility
that th ere m ay b e signi® can t decrem ents for sam e-m ood groups b ecau se of th e usual
decrem ents that occur between sessions (Wester m ann & H ager, 1983). Interestingly, in
E xperiment 1c this w as indeed the case. Sub jects w ho received th e Velten hap py m ood
induction lear ned signi® can tly m ore item s than did sub jects in the Velten sad m oo d
induction. H ow ev er, the m ood-state± depen dent hypothesis w as supported becau se these
su bjects did not forget signi® can tly m ore item s than d id the sad induction g rou p. A m ore
stringent test of the hypoth esis w ould have been to dem an d th at the chan ged -m oo d
g roups should show a signi® can t difference between lear ning an d recall scores; an d
that the sam e-m ood g rou ps should show no signi® can t difference b etween lear ning an d
recall scores. T he ``strict’ ’ m ood-state± d ep endent hypothesis could not have been supported in E xperim ent 1c; further an alyse s revealed that there w ere signi® can t d ifferences
between the lear ning and recall score for subjects in the sam e-m ood g roups, G roup H H :
t(9) = 2 .45, p < .05; G roup SS : t(9) = 2.75, p < .05. We m ust co nclu de, therefore, that the
w ay in w hich th e m ood-state± d ependent hypothesis is stated is critically im portant in
deter m ining w hether or not the effect has been dem o nstr ated. Perhap s the m ost critical
factor co ntributing to the unreliable ® ndings of m ood-state depend enc y is the operational
de® nition of the m ood-state± d ependent retrieval effect.
T he experim ental ® ndings reported here indicate th at the accessibility of retrieval cues
an d therefore the dem o nstratio n of state-dependent retrieval depen ds, in part, on the
ex perien tial context of the in dividual o n different recall occasio ns; on the deg ree of
co rrespondence between the environm ental (lab or atory) contexts for the individ ual o n
different occasions; a nd o n the interaction between the experiential an d enviro nm ental
situations o n each occasion, both of w hich m ak e up the total context. D em o nstratio ns of
the generality an d reliability of m ood-state± dependent retrieval p rovid e a basis of em pirical supp or t from w hich investigatio ns concer ning the nature of retrieval cues in m oodstate± dependent retriev al m ay proceed.
E ich, Weing artner, Stillman , an d G illin (1975) have stated that one of the keys to
understanding hu m an state-dependen t lear ning is the elu cidation o f the nature an d cau se
of retrieval failure. T hey note that to the extent that successful retrieval depends on the
restoratio n of the o rigin al encoding state, decrem ents in recall perform an ce associated
w ith differen t state condition s (e.g. lear n ``hap py’ ’ Ð recall ``sad’ ’ ) m ust re¯ ect a failure o n
the part of the retrieval m echan ism to ® nd relevan t infor m ation that is otherw ise accessible for recall under sam e-state conditions (e.g. lear n ``hap py’ ’ Ð recall ``hap py’ ’ ). A s the
deleterious effect of a state chan ge on recall perfor m an ce re¯ ects a problem in retrieval
rather than in the storage of infor m ation, an d as all acts of recall can be considered as
being m ediated by retrieval cu es (Tulving & M ad ig an , 1970), E ich et al. (1975) argue that
the crux of the problem would seem to lie in the process thro ugh w hich the cues essential
for recall of available in for m ation are subjectively generated. If this is the case, then the
provision of pow erful retrieval cues at th e time of recall should effectively ne gate an y
difference in recall brought about by state m an ipulatio ns.
In their study of the effects of m arijuan a on m em ory E ich et al. (1975) discovered that
state-dependent retrieval w as restricted to the n om inally non-cued test of free recall an d
w as not ap parent w h en recall w as prom pted w ith ap prop riate extralist retrieval cues
(category labels of w ord lists). T hey suggested that a chan ge in the experiential contexts
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M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
305
of su bjects m ay interfere w ith th e accessibility of retrieval cues that presum ably m ediate
free recall but no t cu ed recall. E ich (1980), after reviewing studies of drug-state± dependen t retrieval, concluded that of the variables considered to play key roles in the occurrence of the state-dependent retrieval phenom eno n, the presence or absence of discretely
identi® able retrieval cues in the cognitive enviro nm ent of the rem em berer w as revealed to
m atter m ost. E ich (1980) dem o nstrated th at, w ith very few exceptions, failures to dem onstrate d rug-state± d ependent retrieval are co n® ned to conditions in w hich retrieval is
tested in the presence of explicit rem inders, or ``ob servable’ ’ cuesÐ for exam ple, category
nam e cues (``list’’ cu es), or literal copies of the item s or events to be rem em bered (``copy’ ’
cu es)Ð an d successful dem o nstrations are con® ned to co nditions in w hich testing takes
place in the absence of ob servable cues bu t in the presence of ``invisible’ ’ cues such as
sim ilar experiential co ntexts.
T he experim ents previou sly reported here dem o nstrated m ood-state± dependent
retrieval u nder conditions of free recallÐ th at is, in th e absence of an y ``observable’ ’
cu es related to the m em ory task. K ihlstrom (1991) sug gests that w hen rich, in for m ative
cu es are provided by the retrieval enviro nm ent or can easily be generated by the
individual, the effect of state cues w ill be relatively weak. T h e next experim ent, therefore, investigated the assum ption th at sub jects lear ning an d recalling in the sam e m ood
states, as in the previous experim ents, utilized ``invisible’ ’ cues during recall, an d that a
ch an ge of m ood state interfered w ith the accessib ility of these retrieval cues, lead ing to
signi® can tly poorer recall by sub jects w ho lear ned an d recalled in different m ood states.
If this assum ption is correct, then the provision of ``ob servable’ ’ retrieval cues at the
time of recall should effectively neg ate an y difference in recall resulting from a chan ge
of m ood state. W ithin E ich’ s ter m inology, this represents a failure to dem onstrate statedependent retrieval, as it is a cue-dependent phenom enon; an d the question here w as
w hether m ood-state± d ependent retrieval is cue-depen dent in the sam e m an ner as drugstate± dependent retrieval ap pears to be (E ich , 1980). E ich an d B irn bau m (1987) have
also sug gested that the state-dep end ent m em ory effects produced by psychoactive drugs
are m ediated by their affective properties. T he results of a study by Bartlett an d
San trock (1979), exam in ing m ood-state± depen dent retrieval in young children under
co nditions o f free recall an d cued recall, m irrored the ® ndings of E ich et al. (1975) an d
are co nsistent w ith such reasoning. It w as sug gested by these au thors th at a ch an ge in
m ood red uced the children’ s ab ility to generate ap p ropriate retrieval cues in a freerecall test, an d that d rugs are not necessary to create this effect. T he purpose of
E xperiment 2 w as to investigate the effects of induced m ood on m em ory under conditions of cued recall.
E X P E R IM E N T 2
T he m usic m ood-induction procedure w as used to in duce hap py an d sad m ood states in
su bjects. T he design, m em ory task, an d general procedure were identical to that of
E xperiment 1, except that subjects w ere presented w ith an ob servable ``copy’ ’ cu e at
the tim e of recall on D ay 2. It w as predicted that providing sub jects w ith a discretely
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KEN EA LY
identi® able retrieval cue at time of recall would ``over ride’ ’ the deleterious effects of a
ch an ge of m ood state at recall. W ith respect to the issue of w hat constitutes an effective
cu e for the recovery of inform ation rendered inaccessible for recall as a conseq uen ce of a
ch an ge of m ood state, the encoding speci® city hypothesis (Thom so n & Tulving, 1 970)
holds that only those cues present at encoding w ill b e effective retrieval cues. It w as
therefore decided to use the b asic visual outline of the m ap p resented to subjects in the
initial m em ory task, w itho ut the nam es an d visual representation s of item s, as an observable ``copy’ ’ cu e at the time of recall on D ay 2. It w as hypothesiz ed that providing su bjects
w ith a visual ``cu e’ ’ at tim e of recall w ould facilitate rem em berin g reg ardless of m ood
state; subjects learnin g an d recalling m aterial in different m ood states w ould not have
signi® can tly g reater decrem ents in recall than would sub jects lear ning an d recalling in the
sam e m ood states.
M e th o d
S u b j e c ts
Twen ty-® ve ® rs t- an d secon d- year fem ale u nd erg ra du ate s tu d ents w ere r ecr uited as su bjects.
T h e age of the 24 su bjects w h o p articipated in th e exp erim en t ran ged fr om 20 to 25 years, w ith a
m ean age of 21.5 years.
Pro ce d u re
W h en th ey re tu r n ed on D ay 2, after th e ap p rop r iate m ood ind u ction , sub jects w ere sh ow n th e
basic visu al ou tline of the m ap th at th ey h ad lear n t the d ay be fore, w ith n am es an d visu al rep resen tation s of item s exclud ed. T h ey wer e ask ed to recall as m an y of th e instr u ction s th at accom p an ied th e
m ap as the y could rem e m ber fro m th e d ay before. T h e m ap cu e w as p resen t for 1 m in an d w as th en
rem oved be fore sub jects’ cu ed r ecall. T he nu m ber of item s cor rectly n am ed by each su bject w as
taken as their recall score.
R e s u lts
M ood M ea sures. O ne su bject failed to reach the m ood acceptance criterio n an d did
not retur n o n D ay 2. Table 3 show s the effect of th e hap py an d sad m ood ind uctions as
rated by su bjects on the th ree 0± 100 m ood scales. T he patter n of results w ith respect to
m ood m an ipu lation w as identical to that found in E xperiment 1.
M ood a nd M emory. M ood induction did not differentially affect lear ning perfor m an ce o n D ay 1Ð there w as no sign i® can t difference betwen the lear ning scores of sad
(m ean = 18.7, S D = 0.78) an d hap py (m ean = 18.5, S D = 1.15) subjects on D ay 1, t(22) =
0.2 1, p > .05. H ow ever, m ood induction d id differen tially affect recall perfor m an ce o n
D ay 2Ð there w as a signi® can t d ifference between recall scores of sad (m ean = 14.8, S D =
2.8 3) and h ap py (m ean = 17.8, S D= 1.14) su bjects o n D ay 2, t(22) = 3.40, p < .01.
Independent t test an alysis sh ow ed that the decrem ents in recall of the sam e-state
g roups (H H + SS), m ean = 1.67 item s, com pared to the decrem ents in recall of the
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M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
307
ch an ged-state g roups (H S + SH ), m ean = 3.08 item s, w ere not signi® cantly different. A s
predicted , cueing overrode the state-dependent effect on recall, t(22) = 1.378, p > .05.
H owever, the decrem ent in recall of subjects w ho lear ned in a hap py m ood an d recalled in
a sad m ood (H S), m ean = 5.67 item s, w as signi® can tly g reater than that of the other three
g roups [com parison w ith sam e-state group (SS ), m ean = 2.5 item s, t(10) = 2 .65, p < .05].
Table 4 show s th e lear ning an d recall scores from the four g roup s of sub jects, tog ether
w ith the m ean decrem ents in recall for the sam e-state g roups an d the chan ged-state
g roups.
T here w as a signi® can t difference in the dissociation decrem ents of subjects in the two
g roups w ho recalled in a m ood state different from the o ne in w h ich th ey had lear ned.
Subjects w ho lear ned in a hap py m ood an d recalled in a sad m ood (g rou p 2: H S; m ean
decrem ent = 5.7 , S D = 1.63) forgot signi® can tly m ore item s than d id sub jects w h o
lear ned in a sad m ood an d recalled in a hap py m ood (g roup 4 : SH ; m ean decrem ent =
0.8 , S D = 0.41, t(10) = 7.35, p < .001).
TA BLE 3
E f fe c ts o f H a p p y a n d S a d M o o d In d u c ti o n s
Experiment 2
Experiment 3
Mood I nduction
M ood I nduction
M ea sure*
Da y 1
Da y 2
Da y 1
Da y 2
Group 1
Hap piness
Anxiety
S ad ness
Happ y
66 .0
12 .6
15 .3
H ap py
67.3 ns
13.3 ns
16.7 ns
Hap py
62.6
15.6
19.2
Happ y
61.6 ns
13.2 ns
21.4 ns
Group 2
Hap piness
Anxiety
S ad ness
Happ y
64 .2
11 .5
14 .8
S ad
17.5 **
9.2 ns
65.2 **
Hap py
68.6
10.4
17.6
Sad
20.0 **
11.6 ns
64.1 **
Group 3
Hap piness
Anxiety
S ad ness
Sad
21 .8
10 .3
66 .5
S ad
19.5 ns
12.5 ns
69.2 ns
Sad
18.8
14.0
68.8
Sad
17.6 ns
13.4 ns
63.9 ns
Group 4
Hap piness
Anxiety
S ad ness
Sad
18 .2
11 .3
65 .8
H ap py
58.3 **
11.8 ns
14.2 **
Sad
17.2
10.8
66.6
Happ y
66.8 **
11.4 ns
18.6 **
* M ean of subjects’ ratin gs o n 0± 100 scales.
** S ign i® can t differen ce betwee n m ood ratin gs o n Day 1 and D ay 2,
p < .001.
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KEN EA LY
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D is cu s s io n
M ood-state± dependent retrieval w as not dem on strated under all the con ditions of cued
recall. C han ging m ood state at recall produced an asym m etrical dissociation of m aterial
from m em ory. Sub jects lear nin g in a hap py m ood an d recalling in a sad m oo d had
signi® can t decrem en ts in recall, even though they w ere provided w ith a visual cue at
time of recall. H ow ever, presentation of a visual cue at tim e of recall provided su bjects
lear ning in a sad m ood an d recalling in a hap py m ood w ith an effective cu e that enabled
them to retrieve m aterial from m em ory desp ite a chan ge of m ood state at recall; these
su bjects did not have signi® can t decrem ents in recall.
T he observed asym m etrical dissociatio n can not be explained by a difference in the
initial learn ing scores of sub jects in the different g roups, as m ood o n D ay 1 did not affect
lear ning scores; there w as no signi® can t difference in th e lear ning scores of hap py an d sad
su bjects.
M ood-state± depen den t re trieval, then, ap peared to be cue-depen dent under certain
co nditions of m ood state. Providin g a visual cue at the tim e of recall enabled hap py-m ood
su bjects to rem em ber m aterial that they lear ned w hile in a sad m ood but ap peared not to
en able sad-m ood subjects to rem em ber m aterial lear nt w hilst they w ere in a hap py m ood.
It m ay be that subjects in a sad m ood are particu larly suspicious of experimental ``aids’ ’ ,
or lack the m otivation to utilize such cues effectively. It has been suggested that depression m ight not fundam entally im pair the resources required for good perfor m an ce o n
unintentional learn ing tasks (H ertel & Rud e, 1991), b ut that depression m ay affect the
initiation of cognitive processes, such as spontaneous use of strate gies an d the m otivatio n
to u tilize extern al cues effectively (H ertel & H ardin, 1990).
A n alter native explana tion for these ® ndings is that the ``cue’ ’ m ay have been so
obvious that subjects w ere able to w ork out from the visual representatio n of the m ap
those item s that contained directional com ponents (``tur n right’ ’ ; ``turn left’ ’ , etc.). In
order to deter m in e w hether this m ight account for the high recall scores of som e su bjects
on D ay 2, the seven item s containing only directional infor m ation were rem oved from the
data, w hich were then re-an alysed. E ssentially the sam e patter n concerning d ifferences
em erged. T he visual outline of the m ap did not therefore constitute a recall test w here
su bjects w ere m erely presented w ith the ``cor rect’ ’ item s, as the data rem ain essentially
the sam e w hen th ese item s are discoun ted; the ``cue’ ’ also ap peared to have facilitated
recall of the non-directional item s.
It seem s intuitively likely th at sad -m ood subjects, being in a neg ative m ood state,
m ight m ore read ily w ish to utilize an ap propriate retrieval cue in order to recall m aterial
from a hap pier, m ore positive time, becau se an effective cue m ay not o nly b ring to m in d
the m aterial encoded w ith the cue but also th e m em ory of the particular m ood state in
w hich it w as encod ed. H owever, the ® ndings observed in this experim ent are not consisten t w ith this sup position. In the event, b efore com ing to an y ® r m conclusio ns reg arding the issue, it w as d ecided to replicate this experiment in part in order to investigate the
reliability of the ® ndings.
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
309
TA BLE 4
M e a n L e a r n in g a n d R e ca ll S co r e s
Experiment 2
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Group
HH
SS
HS
SH
Experiment 3
Da y 1
Da y 2
Da y 1
Lea rning
Cued
R eca ll
Lea rning
Da y 2
Free
Reca ll ( 1)
Cued
R eca ll
Free
R eca ll ( 2)
Mea n
SD
M ea n
SD
M ea n
SD
M ea n
SD
M ea n
SD
M ea n
SD
18.0
18.5
19.2
18.8
0.63
0.55
1.33
0.98
17.2
16.0
13.5
18.1
0.7 5
2.6 8
2.5 9
1.2 1
18.6
18.2
18.8
18.4
0.89
1.09
0.83
1.52
18.4
17.4
14.2
13.2
1.51
1.14
2.16
1.92
18.0
16.8
18.2
17.0
1.58
1.64
0.84
1.22
17.4
16.6
14.0
16.8
1.14
0.89
1.82
0.84
E X P E R IM E N T 3
In the p revious experiment the conditions of retrieval w ith resp ect to the p resence or
absence of exp licit (``observable’ ’ ) cues were held co nstantÐ all sub jects retrieved m aterial
in a cu ed recall condition w ith the provision of an ob servable ``copy’ ’ cue. In ad dition to
investigating th e reliability of the previous experimental ® ndings, the present experim ent
co ncer ns the effects of varying the retrieval cond ition s in a w ithin-subject design, w hich
would allow for an investigatio n of the nature of retrieval cues an d their transfer effects.
L eight an d E llis (1981), usin g th e Velten m ood-ind uction procedure, have previously
investigated th e role of depressed m o od induction on the tran sfe r of coding strategies.
T hey found that th e m ood state induced on D ay 1 recall deter m ined subseq uent recall of
a new list 24 hours later, indicating the tran sfer of coding strategies. T hey su ggest that
train ing under a depressed m ood resulted in the ad option of inef® cient codin g strate gies,
w hich w ere tran sferred to seco nd-list lear ning regard less of m ood state o n the secon d
day; an d that neutral m oo d in training enabled sub jects to ad opt a m ore ef® cient org an izational strategy, w hich persisted into the tran sfer task even w hen tran sfer followed a
depressed m ood induction . T he interest in the previous experiment reported h ere w as in
retrieval processes rather than encod ing strate gies (as an initial lear ning criterion w as
imposed in these experiments), but it seem s likely that if subjects are presented w ith an
effective retrieval cue at th e tim e of recall (cued-recall) that is cap able of neg ating the
effects of a chan ge of m o od state, utilization of such a cu e m ay tran sfer to later recall
co nditions w here a cue is not explicitly presen ted (free-recall) an d lead to effective
retrieval of m aterial reg ard less of m ood state.
E ich (1980) has noted that by m an ipulating the presence or absence of exp licit list cues
(e.g. cate go ry nam es) in the cognitive env ironm en t of the rem em berer, it is possible to
dem o nstrate both the occurren ce an d the erasure of state dependence w ithin one an d the
sam e experiencing individual. E ich et al. (1975), studying the effects of m arijuan a states,
have dem o nstrated state-d ependent retrieval und er conditions of free recall an d erasu re of
the state-dependent effect under conditions of cued recall, w ith the p resence of observable cues. Similar interactions have been obser ved by S w an so n an d K insbour ne (1976),
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w hose experim ent focused on the state-dep end ent effects of m ethylphenidate (Ritalin) in
hyperactive children, an d by Weing artner (1978) in a study o f eserine-p roduced statedependent retrieval in ad ults. H avin g dem onstrated m ood-state± dep end ent retrieval in a
free-recall situation followed by erasure of th e effect in a cued-recall situatio n, the question
of interest, then, is w hether m aterial rem ains m ood-state± dependent in a later free-recall
situation, or w heth er the previous experience of an effective cue w ill enable the in dividual
effectively to retrieve infor m atio n again at a later tim e, reg ardless of m ood state.
W ithin everyday lear ning an d rem em b ering ter m s, this m ay be seen as an alogous to a
situation w here an ind ividual in a sad or depressed m oo d w ho co nsistently rem em bers
events an d ep isodes that occurred previously in a similar m ood state is presented w ith a
cu e (e.g a photog rap h, or som e other m em orabilia) w hich effectively enables them to
recall incid ents that occur red in hap pier m o od states. A lthough it is acknow ledged th at
the experiments here refer to a highly speci® c set of item s, this an alogy suggests that it
m ay then be possible for such an individu al to self-gen erate ap propriate retrieval cues,
sh ou ld they once m ore ® nd them selves in a sad or d epressed m ood, w hich w ill enable
them effectively to recall incidents from a hap pier tim e.
T he purpose of E xperim ent 3, then, w as to investigate the cue-dependent n ature of
m ood-state± dependent retrieval using a w ithin-subjects design. A ll m ood-induced subjects w ere asked to recall under three conditions: free recall, followed by cued recall (w ith
presentation of a visual cue), followed by free recall again.
T he general hypothesis investigated w as w hether m aterial that ap pears inaccessible to
su bjects w h o free-call in a d ifferent m ood state to that in w hich they lear n the m aterial
(state-dependent retrieval) b ecom es accessible under conditions of cued recall, reg ardless
of a chan ge o f m ood state at the tim e of recall (erasure of state-dep endent retrieval) an d
rem ains accessible in a later free-recall situ atio n, through the tran sfer of ef® cient retrieval
strategies.
M e th o d
S u b j e c ts
Twen ty-® ve ® r st- an d secon d -y ear fem ale u nd erg rad u ate stu d en ts w ere recru ited . T h e age of th e
20 su bjects w h o p articipated in th e exp erim ent r an ged fro m 20 to 36 years, w ith a m ean age of 23.3
year s.
Pro ce d u re
T h e sam e m usic m ood -in d uction pro ced ur e w as u sed to ind uce h ap py an d sad m ood state s in
su bjects. T h e d esign , m em ory task , an d gen eral p ro ced u re were iden tical to th e p reviou s exp erim en ts, w ith th e exc eption of th e recall sessio n on D ay 2.
O n D ay 2, after th e ap p ro p riate m ood ind uction , sub jects w ere ask ed to recall as m any of th e
instru ction s th at accom p an ied th e m ap as th ey cou ld rem em ber fro m th e d ay befor e, w ithout ag ain
refer rin g to th e m ap. Im m ediately after th is free-re call sessio n the y w ere sh ow n th e visua l ou tline of
the m ap (n am es an d visu al rep resen tatio ns of item s w ere exclud ed) an d were ask ed ag ain to recall as
m an y of th e instru ction s th at accom p an ied th e m ap as th ey cou ld rem em ber fr om th e d ay befor e
(cu ed recall). T h e d ur atio n of m ap cueing w as 1 m inÐ th e sam e as in E xp erim en t 2. A fter an interval
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
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of ap prox im ately 10 m in, d u ring w hich tim e th e ap p ro p riate m u sic w as p laying qu ietly in the backgr ou n d , su bjects w ere again ask ed to free-re call as m an y of th e instru ctio ns as they cou ld rem em ber
w ithou t ag ain refer rin g to the m ap. T h e nu m ber of ite m s cor rectly n am ed by each su bject in each
con d ition w as taken as th eir recall score for th at p articu lar co n dition .
R e s u lts
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M ood M ea sures. Two sub jects did not m eet the m ood accep tan ce criterion, an d three
su bjects failed to return on D ay 2. Table 3 show s the effect of the hap py an d sad m ood
inductions. T he patter n of results w ith respect to m ood m an ipulation w as identical to that
found in E xperiments 1 an d 2.
M ood a nd M emory. Table 4 show s the m ean lear ning an d recall scores for sub jects in
the three conditions of recall. M ood induction did not differen tially affect lear nin g
perfor m an ce on D ay 1Ð
th ere w as no sign i® can t difference between the lear ning scores
of hap py (m ean = 18.7, S D = 0.82) an d sad (m ean = 18.3, S D = 1.25) subjects on D ay 1,
t(18) = 0.84, p > .05.
A percentage score w as derived for each subject. T he num ber of item s cor rectly
recalled by each su bject on D ay 2 w as expressed as a p ercentag e of the num ber of item s
lear nt by that subject on D ay 1. T he percentages in Figure 1 refer to the m ean percentage
(unw eighted ) scores of subjects in each g ro up. Sub jects w ho learn ed an d recalled in the
sam e m ood states had essentially similar recall scores in all three conditions, an d the recall
scores on D ay 2 ran ged from 15 item s to 20 item s. T he m ean percentage of item s lear nt
on D ay 1 that w ere cor rectly recalled by subjects w ho lear ned in a sad m ood an d recalled
in a hap py m ood on D ay 2 w as 71.6% o f item s in the ® rst free-recall session; this w as
improved to a m ean of 92.2% in the cued-recall sessio n an d m aintained at a m ean of
91.4% cor rect in the second free-recall sessio n. H ow ever, the m ean percentage of item s
lear nt that w ere correctly recalled by sub jects w ho lear ned in a hap py m ood an d recalled
in a sad m ood on D ay 2 w as 75.2% of item s in the ® rst free-recall sessio n, w hich
improved to a m ean of 96.8% correct in the cued-recall sessio n, bu t w hich w as not
m aintained in th e second free-recall session, w here the m ean percentage recall w as
only 74.2% of the item s lear nt on D ay 1.
A dopting the previous hypothesis-driven an alysis for Ex periment 3 w as in suf® cient
becau se of the possibility of car ry-over effects from the ® rst recall con dition to the cued
recall an d from the cued recall to the second free-recall co ndition. T his rationale led to a
ch an ge o f ap proach an d statistical an alysis of data from this experiment. T he signi® can ce of
the patter n of results show n in F igure 1 w as tested in a three-way an alysis of variance, w ith
repeated m easures o n one factor; w ith m ood o n D ay 1 (Factor A ), m ood on D ay 2 (Factor
B), an d condition of recall (Factor C ). T he repeated-m easures Factor C had three conditions (levels) of re call: free recall (1) vs. cued recall vs. free recall (2). T he dependent
variables were the num bers of item s cor rectly recalled in each of the three conditions o n
D ay 2 as a percentage of th e num b er of item s lear nt by each subject o n D ay 1 (recall scores).
T here w ere no signi® can t m ain effects of m ood o n D ay 1 or on D ay 2. H ow ever, there
w as a signi® can t effect of recall condition o n D ay 2, F(2, 32) = 20.22, p < .001, a
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F IG . 1 .
M o o d -s t a t e - d e p e n d e n t e f f e c t s u n d e r t h r e e c o n d i t i o n s o f r e c a l l o n D a y 2 .
signi® can t interactio n between m ood on D ay 1 an d m ood on D ay 2, F(1, 16 ) = 25.30, p <
.00 1; a signi® cant interaction between m ood on D ay 1 an d recall con ditions on D ay 2,
F(2, 32) = 9.63, p < .01, a sig ni® can t interaction between m ood on D ay 2 an d recall
co nditions, F(2, 32) = 7.10, P < .01, an d, ® nally, a highly signi® can t three-w ay interactio n
between m ood on D ay 1, m ood o n D ay 2, an d recall condition on D ay 2, F(2, 32) = 31.08,
p < .001.
In ord er to explore th e three-w ay interaction (A 3 B 3 C ) in g reater detail, tests of
sim ple m ain effects were used (K irk, 19 68, p. 291). T hese post h oc com pariso ns of m ean s
co ntrasted sam e-m ood an d chan ged-m ood sub jects sep ar ately for each m em ory test.
B etween-groups A na lyses. T he b etween-g roups an alyses revealed that the difference
on D ay 2 b etween recall o f subjects in g roup H H (hap py on D ay 1, h ap py o n D ay 2)
an d subjects in G roup H S (hap py on D ay 1, sad on D ay 2) w as signi® can t in the ® rst
free-recall co ndition, F(1, 3) = 35.01, p < .01, w as n ot sign i® can t in the cued-recall
co ndition, F(1, 3) < 1, an d w as signi® can t in the second free-recall co ndition, F(1, 3) =
49.2, p < .01.
Tur ning to su bjects in the g roup SS (sad o n D ay 1, sad on D ay 2) an d g roup S H (sad
on D ay 1, hap py on D ay 2), the d ifference o n D ay 2 between subjects’ recall in th ese two
g roups w as signi® can t in the ® rst free-recall condition, F(1, 3) = 36.2, p < .01, an d w as
M O O D -S T A T E ± D E P E N D E N T R E T R I E V A L
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not signi® can t in the cued-recall co nd ition, F(1, 3) < 1, neither w as the difference signi® can t in the second free-recall condition, F(1, 3) < 1.
Within-groups A na lyses. T he w ithin-g roups an alyse s exam ined the recall of su bjects
w ithin the four g ro up s across the th ree conditions of recall o n D ay 2. T his revealed that the
recall of su bjects in different m ood states on D ay 2 differed sign i® can tly across conditions:
G roup H S, F(2, 32) = 71.3 5, p < .001, an d g roup SH , F(2, 32) = 59.59, p < .001; w hereas
recall of subjects in th e sam e m ood states on D ay 2 did not differ across co nditions: g rou p
H H , F(2, 32) = 3.01, n.s., an d g roup S S, F(2, 32) = 2.05, n .s.
To explore the signi® can t effects in g reater detail, a series of N ew m an -K euls’ com p arison s were co nducted on th e m ean s of each co ndition for G roups H S an d SH separately,
w ith p set at .05. T hese revealed that, for g roup H S, cued recall w as superior to each of
the free-recall co nditions, ps < .05, w hich them selves did not differ, p > .05. For g roup
SH , cued recall w as superior to the ® rst free-recall condition , p < .05, but did not d iffer
from the second free-recall co ndition, p > .05, an d this second free-recall co ndition w as
su perior to the ® rst free-recall con dition, p < .05 (see Figure 1).
D is cu s s io n
T he results showed that listen ing to m usic successfully induced hap piness an d sad ness in
su bjects. M ood induction did not differentially affect subjects’ ab ility to lear n the task o n
D ay 1Ð there w as no signi® can t difference between the lear ning scores of hap py induction an d sad induction subjects o n D ay 1.
T he p rediction of this exp eriment w as that the ® rst free-recall perfor m an ce of
su bjects would show a state-dependent retrieval effect an d that cued-recall perfor m an ce
would not. T he data from the between-g roups an alyses support this prediction ; a statedependent retrieval effect w as observed in the ® rst free-recall cond ition, w ith su bjects
w ho lear ned an d recalled in the sam e m ood states recalling signi® can tly m ore item s
than subjects w h o lear ned an d recalled in different m ood states. T his state-dependent
effect w as n ot ap parent in the cued-recall co ndition, w here there w ere no signi® can t
differences between the recall scores of subjects w ho recalled in the sam e m ood states
an d subjects w h o recalled in different m ood states (to those of D ay 1), indicating that
the provision of a ``copy’ ’ cu e at tim e of recall en abled all subjects to retrieve m aterial
effectively reg ardless of a chan ge of m ood state. T he ® nding of E xperim ent 2, that the
cu e w as effective fo r sub jects w ho lear ned in a sad m ood an d recalled in a hap py m ood
but not for subjects w ho lear ned in a hap py m ood an d recalled in a sad m ood w as not
replicated h ere; indeed, Table 4 sh ow s that not only w as the cu e m ore effective for
su bjects in g roup H S in this experiment com pared w ith subjects in the previous
ex periment, b ut also that su bjects in this group h ad higher m ean recall scores in the
cu ed condition than d id subjects in g roup SH . T he data m ay be accounted for by the
fact th at subjects were required to free-recall in this experiment before being presented
w ith a retrieval cue, an d this initial recall m ay have enabled them to use the cue m ore
effectively in the cued-recall session.
W ith respect to the tran sfer of effective retrieval strategies, the question investigated
w as w heth er the state-depen dent retrieval effect erased in the cued-recall condition w ould
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reap pear in a second free-re call condition, or w hether subjects would b e able to utilize the
effective retrieval cue provided in the cu ed-recall condition to ne gate the deleterious
effect of a chan ge of m ood state. T he b etween -g roup s an alysis indicates the re-em ergence
of the state-dependent effect for su bjects w ho w ere recalling in a sad m ood after having
lear ned in a h ap py m ood Ð their percentage recall w as signi® can tly lower than th at of
su bjects w ho had lear ned an d recalled in a hap py m ood state. H ow ever, the percentage
recall scores of subjects w ho learn ed in a sad m ood an d recalled in a hap py m ood were not
signi® can tly d ifferent from those of su bjects w ho learned an d recalled in the sam e sad
m ood states.
T hus it ap p eare d that providin g an observable retrieval cue to su bjects in a sad m ood
en abled them to recall m aterial lear nt w hilst in a previously hap py m ood, but su bjects
ap pear to b e unable to tran sfer this ability to situations w here the cue is n ot explicitly
presented. T he w ithin-group an alyses su pport this explanatio n in that subjects w ho
lear ned in hap py m oo d an d recalled in a sad m ood showed signi® can tly better recall in
the cued-recall co ndition com p ared to the ® rst free-recall condition, but that this
improvem ent w as not su stained in the second free-recall condition, w here percentage
recall reverted to the poor perfor m an ce ob served in the ® rst free-recall co nditionÐ that
is, recall w as ag ain affected by a chan ge of m ood state from the initial lear ning m ood state.
By com parison , sub jects w ho learn ed in a sad m ood an d recalled in a hap py m ood show ed
signi® can tly su perior recall in the cued condition com pared to the ® rst free-recall condition, an d th is improvem ent in recall w as m aintained in the second free-recall co ndition,
w here p recentage recall scores were signi® can tly higher than those of the ® r st free-recall
co ndition. For subjects in this group, the provisio n of an observable ``copy’ ’ cue enabled
them effectively to override the deleterious effects of a chan ge of m ood state an d to
m aintain this effective retrieval of m aterial in a further free-recall condition.
In co nclusion, the som ew hat unreliable natu re of the effectiveness of ob servable
``copy’ ’ cues to over ride the deleterious effects of a chan ge of m oo d state w ar ran ts further
investig ation; cues w ere show n to b e effective in this experiment, but not und er all
co nditions in E xperiment 2. T he ® n dings reported here suggest that m aking accessible
to subjects in a sad m ood m aterial that they previously encoded in a hap py m ood does not
en able them to self-generate ap propriate retrieval cu es to access that sam e m aterial at a
later time. B y an alogy, the results m ay also sug gest that once som eo ne in a hap py m ood is
able to retrieve m aterial encoded in a sad m ood, the accessibility of this m aterial is
retained or tran sfer red to subseq uent occasio ns of recall, reg ardless of th e dissim ilarity
between encoding an d retrieval m ood states.
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Origina l ma nuscript receiv ed 28 October 1994
Accepted revision receiv ed 25 J uly 1996