S u m m a r y
Revonsuo A & Valli K (2000)
The Reinterpretation of Dreams
An evolutionary hypothesis of the function of dreaming
Psykologia 35:472-484. Vammala ISSN 0355-1067
Several theories claim that dreaming is a random by-product of REM sleep
physiology and does not serve any natural function. Phenomenal dream
content, however, is not as disorganized as such views imply. The form and
content of dreams is not random but organized and selective: during
dreaming, the brain constructs a complex model of the world in which certain
types of elements, when compared to waking life, are underrepresented
whereas others are overrepresented. Furthermore, dream content is
consistently and powerfully modulated by certain types of waking
experiences. On the basis of this evidence, I put forward the hypothesis
that the biological function of dreaming is to simulate threatening events,
and to rehearse threat perception and threat avoidance. To evaluate this
hypothesis, we need to consider the original evolutionary context of
dreaming and the possible traces it has left in the dream content of the
present human population. In the ancestral environment human life was short
and full of threats. Any behavioral advantage in dealing with highly
dangerous events would have increased the probability of reproductive
success. A dream production mechanism that tends to select threatening
waking events and simulate them over and over again in various combinations
would have been valuable for the development and maintenance of threat
avoidance skills. Empirical evidence from normative dream content,
children's dreams, recurrent dreams, nightmares, post-traumatic dreams and
the dreams of hunter-gatherers indicates that our dream production
mechanisms are in fact specialized in the simulation of threatening events,
and thus provides support to the threat simulation hypothesis of the
function of dreaming.
Key words:
Function of dreaming, dream content analysis, nightmares, evolution of
consciousness, evolutionary psychology, threat perception.
Antti Revonsuo, Ph.D., Senior Fellow, Academy of Finland. Department of
Philosophy, Center for Cognitive Neuroscience, University of Turku,
FIN-20014 Turku, Finland
Katja Valli, M.A., Department of Philosophy, University of Turku,
FIN20014-Turku, Finland.
