Mood Dependence 71years later, in an article written with John Mayer, Bower
came to a very different conclusion, claiming that MDM is an
“unreliable, chance event, possibly due to subtle experimen-
tal demand” (Bower & Mayer, 1989, p. 145).
What happened? How is it possible that in less than a
decade, mood dependence could go from being a “genuine
phenomenon” to an “unreliable, chance event”?
What happened was that, although several early studies
secured strong evidence of MDM, several later ones showed
no sign whatsoever of the phenomenon (see Blaney, 1986;
Bower, 1987; Eich, 1989; Ucros, 1989). Moreover, attempts
to replicate positive results rarely succeeded, even when
undertaken by the same researcher using similar materials,
tasks, and mood-modification techniques (see Bower &
Mayer, 1989; Singer & Salovey, 1988). This accounts not
only for Bower’s change of opinion, but also for Ellis and
Hunt’s (1989) claim that “mood-state dependency in memory
presents more puzzles than solutions” (p. 280) and for
Kihlstrom’s (1989) comment that MDM “has proved to have
the qualities of a will-o’-the-wisp” (p. 26).
Plainly, any effect as erratic as MDM appears to be must
be considered a problem. Despite decades of dedicated re-
search, it remains unclear whether mood dependence is a
real, reliable phenomenon of memory. But is MDM a prob-
lem worth worrying about, and is it important enough to pur-
sue? Many researchers maintain that it is, for the concept
has significant implications for both cognitive and clinical
psychology.
With respect to cognitive implications, Bower has allowed
that when he began working on MDM, he was “occasionally
chided by research friends for even bothering to demonstrate
such an ‘obvious’ triviality as that one’s emotional state could
serve as a context for learning” (Bower & Mayer, 1989,
p. 152). Although the criticism seems ironic today, it was
incisive at the time, for many theories strongly suggested that
memory should be mood dependent. These theories included
the early drive-as-stimulus views held by Hull (1943) and
Miller (1950), as well as such later ideas as Baddeley’s
(1982) distinction between independent and interactive
contexts, Bower’s (1981) network model of emotion, and
Tulving’s (1983) encoding specificity principle (also see the
chapter by Roediger & Marsh in this volume). Thus, the fre-
quent failure to demonstrate MDM reflects badly on many
classic and contemporary theories of memory, and it blocks
understanding of the basic issue of how context influences
learning and remembering.
With respect to clinical implications, a key proposi-
tion in the prologue to Breuer and Freud’s (1895/1957)
Studies on Hysteriastates that “hysterics suffer mainly from
reminiscences” (p. 7). Breuer and Freud believed, as did
many of their contemporaries (most notably Janet, 1889),
that the grand-mal seizures, sleepwalking episodes, and
other bizarre symptoms shown by hysteric patients were the
behavioral by-products of earlier traumatic experiences, ex-
periences that were now shielded behind a dense amnesic
barrier, rendering them impervious to deliberate, conscious
recall. In later sections of theStudies,Freud argued that the
hysteric’s amnesia was the result of repression: motivated
forgetting meant to protect the ego, or the act of keeping
something—in this case, traumatic recollections—out of
awareness (see Erdelyi & Goldberg, 1979).
Breuer, however, saw the matter differently, and in terms
that can be understood today as an extreme example of
mood dependence. Breuer maintained that traumatic events,
by virtue of their intense emotionality, are experienced in an
altered or “hypnoid” state of consciousness that is intrinsi-
cally different from the individual’s normal state. On this
view, amnesia occurs not because hysteric patients do not
wantto remember their traumatic experiences, but rather,
because theycannotremember, owing to the discontinuity
between their hypnoid and normal states of consciousness.
Although Breuer did not deny the importance of repression,
he was quick to cite ideas that concurred with his hypnoid
hypothesis, including Delboeuf’s claim that “We can now
explain how the hypnotist promotes cure [of hysteria]. He
puts the subject back into the state in which his trouble first
appeared and uses words to combat that trouble, as it now
makes fresh emergence” (Breuer & Freud, 1895/1957, p. 7,
fn. 1).
Since cases of full-blown hysteria are seldom seen today,
it is easy to dismiss the work of Breuer, Janet, and their
contemporaries as quaint and outmoded. Indeed, even in
its own era, the concept of hypnoid states received short
shrift: Breuer himself did little to promote the idea, and Freud
was busy carving repression into “the foundation-stone on
which the whole structure of psychoanalysis rests” (Freud,
1914/1957, p. 16). Nonetheless, vestiges of the hypnoid
hypothesis can be seen in a number of contemporary clinical
accounts. For instance, Weingartner and his colleagues have
conjectured that mood dependence is a causal factor in the
memory deficits displayed by psychiatric patients who cycle
between states of mania and normal mood (Weingartner,
1978; Weingartner, Miller, & Murphy, 1977). In addition to
bipolar illness, MDM has been implicated in such diverse
disorders as alcoholic blackout, chronic depression, psy-
chogenic amnesia, and multiple personality disorder (see
Goodwin, 1974; Nissen, Ross, Willingham, MacKenzie, &
Schacter, 1988; Reus, Weingartner, & Post, 1979).