Further evidence comes from brain lesions. Damage
to the ventral-mesial quadrant of the frontal lobe,
which is involved in emotional motivation, or to
the parietotemporo-occipital (TPO) junction, which
is part of the sensory areas, reduces or obliterates
dream recall while leaving REM sleep essentially
normal (Solms, 2000). In other words, REM is neither
necessary nor sufficient for dreaming.
Second, REM can occur when dreaming seems
unlikely or even impossible. For example, human
foetuses spend about 15 hours a day in REM sleep,
babies spend less as they grow older, and children
and adults less still. Yet foetuses cannot have any-
thing like adult dreams because dreaming depends
on prior experiences and on highly developed cog-
nitive abilities which unborn babies lack. People
with no visual experience, such as those born blind,
dream without visual imagery but in words, ideas,
and emotions, and in auditory, tactile, gustatory, and
olfactory images. Dreams in people who become
blind later in life gradually become less visual and
more tactile (Meaidi et al., 2014). These people have
plenty of experiences and a rich sense of self. But the
new-born baby has neither.
As children grow older, their dreams closely reflect
their developing cognitive abilities. Their dreams turn
from rather static single dream images reported at
age five or six, to more lively and dynamic imagery at
age six or seven, with a dreamed self appearing only
after the age of about seven years (Foulkes, 1993). We
can therefore be sure that, whatever is going on for
a foetus during REM sleep, it is not anything like an
adult’s dream. Hobson has speculated on this basis
that what the mind–brain is doing in babies’ REM
sleep before dreaming appears is preparing itself for
many integrative functions – and among these func-
tions he includes consciousness. He suggests that
REM sleep in early life before dreaming develops can
be thought of as ‘protoconscious’ and as serving the
purpose of allowing us to explore the possibilities
and constraints of a virtual environment: ‘The devel-
opment of consciousness is thus seen as a gradual,
time-consuming and lifelong process that builds on,
and constantly uses, a more primitive innate virtual
reality generator, the properties of which are defined
for us in our dreams’ (Hobson, 2009, p. 808). For Hob-
son, the ability to ‘integrate’ the dream state is what
allows us to become aware of it.argument also made for engagement with novels, drama,
or films). Revonsuo (2000) shows that modern dreams
include far more threatening events than people meet in
waking life, and the dreamer usually engages appropriately
with them. A broader view of ‘dreaming as play’ is proposed
by nicholas Humphrey (1983, 1986). Dreaming tests our
physical, intellectual, and social skills and ‘represents the
most audacious and ingenious of nature’s tricks for educat-
ing her psychologists’ (1983, p. 85).
Flanagan argues that ‘dreams are evolutionary epiphe-
nomena’ and have no adaptive function whatsoever.
‘Dreaming came along as a free rider on a system
designed to think and to sleep’ (2000, pp. 100, 24). there
is growing evidence that sleep plays an important role in
reactivating and consolidating new memories, suggesting
that the content and structure of dreams merely reflect
these processes (Wamsley and stickgold, 2011; Wamsley,
2014). the first theory to relate dreams to memory was
Crick and mitchison’s (1983) proposal that neural net-
works become overloaded during learning and the func-
tion of Rem sleep is to flood them to remove superfluous
connections. In other words, we dream to forget. Hobson
(2002) also connects dreaming to memory consolidation
and considers dreams to be epiphenomenal, but on differ-
ent grounds: that dream content has no significant influ-
ences on waking behaviour, and many people function
perfectly well without recalling their dreams; while the
Rem state, by contrast, functions to minimise free energy
and reduce the complexity of the brain’s model of the
external world (Hobson and Friston, 2012). Along similar
lines, tononi’s ‘synaptic homeostasis’ hypothesis (tononi
and Cirelli, 2003) suggests that sleep regulates the exces-
sive synaptic activation of wakefulness. sleep is the price
we pay for the brain’s plasticity and dreams are a kind of
play amongst its vast repertoire of memories.
the question of whether the conscious experience of dream-
ing plays a functional role or not is part of the wider question
of whether consciousness in general has a function (Chap-
ter 11), and remains unresolved. But either way, we can still
use dreams in our own lives. theories of dream interpreta-
tion, especially those based on Freud’s psychoanalysis, have
not stood the test of time (Webster, 1995; Hobson, 2002),
but studying our own dreams can still reveal our motiva-
tions, hopes, and fears, encourage growing awareness, and
even be a source of creativity and insight.