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by George Christos
Rutgers University Press, 2003
Review by Maura Pilotti, Ph.D. on Jul 21st 2003

Memory and Dreams

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.