In Memory and
Dreams, George Christos presents an interesting and engaging introduction
to research findings regarding REM sleep and discusses theoretical assumptions
about its functional significance.  He
then builds on such findings and theories to deliver his proposal about two
fascinating issues: the cause of sudden infant death syndrome (SIDS) and the
nature of creativity. 

One of the most pleasing features of the book is
that Christos, an Australian mathematician, presents complex issues and their
factual bases in a manner that makes them accessible to readers from different
walks of life without undermining the intricacy of the issues and their
relevance.  He frequently reiterates the
main ideas discussed in each of the 6 chapters of the book so as to allow
readers to maintain their focus on the main picture while fully enjoying the
fine points. 

Another engaging feature of the book is Christos’
overview of the current understanding of the functioning of the brain with
respect to memory and dreaming in which he successfully integrates knowledge
from diverse areas of inquiry (i.e., neurobiology, physiological, evolutionary
and cognitive psychology, and computer science).  He relies on this overview to discuss different theoretical
accounts of how information is stored and retrieved (either intentionally or
accidentally), and of the nature and functional significance of REM sleep.  In doing so, he argues that the
understanding of how human memory works can be gathered not only from
experimental findings, but also from more formal computer models that simulate
some of the functional and architectural aspects of human memory.  Through such models, he argues that memories
are distributed in nature and that a likely outcome of distributed storage is
the generation of spurious memories. 
These can be thought of as self-generated memories fabricated from
information pertaining to different stored memories.  According to Christos, spurious memories, which are usually
deemed a nuisance, are the source of creativity, and REM sleep is primarily
responsible for making these memories available to consciousness.  He argues that during REM sleep the
semi-random firing generated by the brain stem and the reduced inhibitory
functioning of the neocortex provide the breeding ground for the activation of
spurious memories (the same applies to mind-altering drugs).  Unfortunately, the demonstration of the
thesis that spurious memories are the source of creativity focuses on the
Hopfield model, which even the author recognizes as being a biologically
unrealistic simplification of the functioning of any human memory system.  Christos’ focus on this model deprives his
examination of human memory of a more thorough acknowledgment of the findings
and theories of cognitively oriented scientific inquiry.  Nevertheless, the discussion of creativity
contains a scholarly examination of the issue of the functional significance of
REM sleep.  Christos’ presentation of a
variety of theoretical accounts of the nature of REM sleep and dreaming and
their empirical foundations is quite remarkable, but a bit one-sided in favor
of the thesis that REM sleep serves to unlearn (forget) weak stored and
spurious memories and to improve the status of strong memories (either stored
or spurious).  Of course, this is not
surprising since the bolstering of already strong spurious memories is the
centerpiece of his account of creativity. 

The last section of the book is devoted to a
discussion of SIDS, a heartbreaking phenomenon in medical science whose causes
have yet to be clearly understood. 
Christos repeatedly informs the reader that only when no medical (or
criminal) reasons can be found to justify the unexpected death of an infant
while asleep is a diagnosis of SIDS formulated.  This assessment by default, which applies to approximately one in
a thousand live births, underscores the lack of knowledge as to what causes the
sudden death of otherwise healthy infants. 
Christos painstakingly summarizes the known statistical and medical
facts regarding SIDS (e.g., mortality rate fluctuations as a function of
infants’ age with peaks during the second and third months after birth, risk
factors, lack of cyanosis in SIDS cases, etc.), and then compares them with
current theoretical accounts of the possible causes of SIDS.  Christos cleverly demonstrates that each of
these accounts can satisfactorily explain some known facts pertaining to SIDS
but not others, thereby preparing the groundwork for his own account of the
phenomenon.  He claims that the cause of
SIDS is purely psychological and it involves infants who "dream" that
they are back in the safety of their mothers’ womb where they did not need to
breathe on their own because their mothers supplied them with oxygen through
the blood.  As a result, infants stop breathing
and die while asleep.  Wisely, Christos
accompanies this surely controversial account of SIDS with a more parsimonious
one, which does not rely on dreaming and gives SIDS a physiological origin.  According to this more reasonable account,
there are two breathing systems: a fetal system by which oxygen is supplied
through the mother’s blood and a postpartum system that relies on infants’
active breathing.  Christos proposes
that the semi-random stimulation of the brain during REM sleep may accidentally
activate the fetal breathing system, which, in turn, leads infants to stop
breathing and consequently die.  Both
accounts, he claims, are consistent with almost all the known facts regarding
this phenomenon.  Unfortunately,
Christos focuses on the first, more daring account of SIDS and neglects to
elaborate on the latter, even though it lacks precision and its testability
remains an issue.  To compensate for the
latter shortcoming, Christos proposes that a statistical examination of the
time elapsed between sleep onset and death in infants who had been diagnosed as
SIDS cases could provide supporting (albeit mainly correlational) evidence for
the central assumption of his accounts that SIDS occurs during REM sleep (i.e.,
when infants are most likely to dream). 
He also proposes that preventive measures intended to discourage SIDS in
human infants be taken (e.g., placing infants in the supine position for sleep)
to see whether such measures might decrease SIDS rates.  Lastly, he proposes experiments in other
mammals for which evidence of REM sleep exists.  Even though he is unaware of any SIDS recording in such mammals,
he suggests that they be exposed to environmental conditions during sleep that
replicate as closely as possible those experienced in the womb to determine
whether this womb-like environment might increase the rates of SIDS.  Sadly, he leaves the implementation of each
of these proposals to future endeavors undertaken by others, thereby leaving
his claim that SIDS is dependent upon the occurrence of REM sleep or, more
daringly, on dreaming of a womb-like state, untested.

In summary, Christos’ book cleverly integrates
current knowledge of memory’s functioning and REM sleep to address the issues
of the sources of creativity and SIDS. 
Even though his proposals may be questioned on different grounds and
still await testing, their controversial nature is certainly likely to generate
interest in these issues and, by so doing, advance scientific knowledge of two
still puzzling phenomena. 

© 2003 Maura Pilotti

Maura Pilotti,
Ph.D., Department of Psychology, Dowling College, New York.

Categories: Psychology