This year sees the 150th anniversary of the birth of Herman Ebbinghaus, universally acknowledged as the man who first brought the study of learning and memory out of introspection and into the "objectivity" of the laboratory.
My review copy of the Oxford Handbook of Memory arrived as I was about to depart for a major international conference in his honour and deliver an overview paper on the "Theory and practice of memory research for the 21st century". What perfect timing, and what better crib for my lecture, I thought.
The psychologist Endel Tulving is one of the few in the field whose research and writing runs effortlessly from the experimental to the theoretical and who has never been afraid to insist on the need for concepts in what is otherwise an overly empirically driven field.
Tulving and his co-editor, Fergus Craik, have undertaken a monumental task: 39 chapters, 50 distinguished authors, in what is claimed to be the first such compilation - on the dust-jacket, the neuropsychologist Michael Gazzaniga acclaims it as "the most important book on the subject ever published". But then came the shock.
I looked in vain in the index for almost any reference to the work of the 200-odd participants at my conference. Admittedly mine was a primarily European conference and this handbook needs to come with a cautionary subtitle, "Handbook of Anglophone Memory". It is sad to see how pervasive the US NIH (not invented here) syndrome is, in what is after all an overwhelmingly international research field.
However, what first struck me was that not even the most highly visible (and US-based) of the neurophysiologists and molecular biologists, who have made the study of learning and memory central to their work over the past 30 years, are represented in this collection. Even Eric Kandel, joint winner of this year's Nobel prize for his work on the neurobiology of memory, finds no place. How could "the most important book on the subject", joint-edited by so towering a figure, not have noticed what we have been up to all this time?
In fairness, the editors make it clear that they have deliberately chosen not to cover the work of those who study animal learning and memory in the hope of interpreting its intimate brain mechanisms. But the gulf is symbolic of a deeper problem.
Laboratory studies on the molecular and cellular processes that occur during learning and recall - one of hottest of neuroscientific research topics - find that memories are encoded in the brain in terms of changing patterns of connection between nerve cells: patterns that are supposed to "represent" in some way a more or less permanent "memory trace".
But to the authors in the handbook, "memory" is a portmanteau term embracing many different forms, autobiographical and episodic, semantic ("remembering that") and procedural ("remembering how"). "Working memory" occurs at the edge of present consciousness or is called into play when recovering past experience. Imaging studies, well represented in some of the later chapters, but sadly without the dramatic colour representations that we have become accustomed to, find these forms of memory to be differentiated and highly dynamic, engaging many brain regions in time-dependent and fluctuating patterns of neural activity.
The theoretical and conceptual gulf between such an understanding and that offered by neuroscience is the major impediment to any integrated understanding of the brain mechanisms involved in learning, remembering and, indeed, forgetting.
But if neuropsychologists ignore us more cellular folk at their peril, there is much in the handbook for neuroscientists to remind us, immersed as we are in the molecular jungle of transcription factors and post-synaptic potentials, that our memories are above all what define us as human individuals.
When Ebbinghaus took memory into the laboratory, he "scientised" it brilliantly, but in doing so divorced it from real-life subjective experience. This is why lab studies of memorising lists of nonsense syllables and the stuff of a century of research represented in the early chapters of the handbook seem so unrelated to our lived experience.
Fortunately, this scientising tide is beginning to turn. The ecological approach to real-life memory, pioneered by Ulric Neisser, is well represented. Twelve central chapters review "memory in life", from early childhood to the decline associated with Alzheimer's disease. I found the developmental chapters fascinating. Very young infants can already learn and remember - there are even claims for learning in utero, although the length of time they can recall is much reduced compared with older children. That as adults most of us cannot remember events occurring before we are three, so-called "childhood amnesia", is well established, although the chapters point to some exceptions.
I was sorry not to note any discussion of the different quality of childhood memory, with its intense visual and olfactory elements and "photographic" sense. I feel the transition from this to the more linear adult forms of memory gives us some clues as to the developmental brain processes involved.
An important chapter by Katherine Nelson and Robyn Fivush reminds us of what laboratory researchers too easily forget: that learning and remembering are social as well as private acts. How and what we remember are shaped by how we have been parented. Women remember past autobiographic details better than men, and with greater emotional richness. Just why is unknown.
The authors opt for a socialising explanation; it would be interesting to see this correlated with the emerging data from imaging studies showing sex/gender differences in regions of the brain that become activated during learning and recall tasks. But please note, that as brain development is itself a bio-sociocultural phenomenon, this does not imply an essentialist claim!
There is some discussion of so-called "false memory", that is, claims to recall events that are contrary to the historical record. Studies of how well people remember episodes of public significance, for example Margaret Thatcher's resignation, made by comparing their immediate recorded accounts with those made at later times, show how fickle memory may be.
Subjects can fairly readily be made to recall inserted false material, which casts doubt on the many accounts of so-called therapeutically recovered memory of childhood abuse. That such memories can be "real" for those who have them, irrespective of whether their narrative conforms to externally verifiable facts, points yet again to the dynamic nature of memory and to why "re-membering" is an active process, not just consulting some stored computer file.
The book ends with a section on theories of memory, including attempts to build computer simulations of memory processes: so-called connectionist models. While these have given modellers quite a lot of fun, it is not clear if they have helped the empirical study of human memory. Even granted the editors' constraints on material, I would have thought it more illuminating to locate human memory firmly in an evolutionary perspective in this context.
The two final chapters - a review of memory systems by Daniel Schachter and colleagues, and a concluding reflection on "the story of memory and the memory of the story" by Lawrence Weiskrantz - are contemporary and richly informed. Yet if we are to accept Gazzaniga's commendation, we must recognise just how far we have to go in our search of any over-arching theories of memory.
Steven Rose is director, brain and behaviour research group, Open University.
The Oxford Handbook of Memory
Editor - Endel Tulving and Fergus M. Craik
ISBN - 019 512265 8
Publisher - Oxford University Press
Price - £45.00
Pages - 700