Missing crucial monkey business

The field of child development is now so wide, and research progress so rapid, that even experts need to have a broad-ranging encyclopaedia to consult on topics outside their particular areas of expertise. General readers' needs are even greater if they are to make sense of the competing claims in the media on what is required to help disadvantaged children; whether autism is increasing in frequency (and if so, why); what brain imaging can and cannot tell us; whether genes really do determine development; how early experiences can in some circumstances bring about lasting changes in psychological functioning; and what enables some children to overcome stress and adversity.

Does this book meet these needs? Almost inevitably, the answer varies depending on the topic under discussion. The authors include many of the leading people in the field, the quality of the writing is generally high, the text is mostly free of obfuscating jargon and many of the chapters are very interesting, as well as informative. These add up to a set of considerable strengths, and there is much of value to be found in the wide-ranging accounts of different aspects of child development.

The editors are explicit that a degree of selection of topics is necessary, and it would be quite inappropriate to complain that my own selection criteria might have been different. Nevertheless, it is reasonable to consider whether the omissions and inclusions convey an appropriate picture of the state of the art.

With that in mind, the encyclopaedia is surprisingly weak on several of the most exciting and important areas of developmental science, as well as on crucial conceptual/methodological advances and important policy issues.

Neuroscience as a whole does not get much attention, and animal research is scarcely mentioned at all (it does not even appear in the index). Of course, the encyclopaedia is about child development but it is undeniable that investigations in other species have been hugely informative.

Thus, the Nobel prizewinning research by David Hubel and Torsten Wiesel was crucial in showing the role of visual input on the development of the parts of the brain subserving vision. Michael Meaney's research showed how nurturant experiences in early infancy brought about changes in gene expression that mediated long-term effects on the behaviour of the offspring. William Greenough's studies showed how deprivation and environmental enhancement had effects on brain structure and function in adult life as well as in early life. All three areas of research were of fundamental importance in providing an understanding of different forms of biological programming of development (with respect to both concepts and effects). None of this is covered in the encyclopaedia and none of these scientists appears, even in the index. The same applies to Stephen Suomi's pioneering studies of rhesus monkeys with respect to gene-environment interactions.

One of the most important advances in the field of behavioural genetics has been the appreciation that many of the effects of genetic influences depend on co-action between genes and environment. Thus, Kenneth Kendler has emphasised the importance of genetic influences "outside the skin" - meaning the role of indirect effects that depend on the environment as a result of gene-environment correlations and interactions. Similarly, the Canadian research consortium led by Ronald Barr (one of the editors) has argued for the importance of considering how the environment gets "under the skin" by virtue of effects on gene expression, biological programming and neuroendocrine function. All this has revolutionised thinking about child development, but none of it is discussed in the encyclopaedia. There is a good brief account of magnetic resonance brain imaging in the book but, curiously, there is no discussion of how it may be used to study the working of the mind, with respect either to normal functioning or to disorders.

Perhaps the most radical shift in thinking about psychological development has been the appreciation that a developmental perspective is as important for psychopathology in adult life as it is for mental disorders in childhood. Thus, views of schizophrenia have shifted from seeing it as a psychosis of adulthood to the concept that it has neurodevelopmental origins in early life. Longitudinal studies were crucial in bringing about this change, as they have also been in revealing that a majority of mental disorders in early adult life were evident in childhood. The same applies to the long-term risks associated with child abuse and neglect. Yes, the encyclopaedia is about child development, but it would be a very curious concept that assumed that adult outcomes were irrelevant for the understanding of processes in earlier life. This is touched on in the encyclopaedia but not directly discussed.

The same applies to the issues involved in proceeding from correlational evidence to causal inference and to the need to differentiate between children's effects on their environment and the effects of that environment on children's development, and between genetic and environmental mediation.

Several useful methodological chapters touch on these issues, but they are limited in their coverage and certainly do not bring out the key controversies.

There is a good brief chapter on day care but, otherwise, there is limited coverage of interventions designed to foster normal development in children from disadvantaged backgrounds. The important findings of the past decade on the development of children exposed to profoundly depriving institutional care are not discussed. Developmental psychopathology, a major growth area, gets little attention, and the chapters on abnormal functioning are a mixture of the very good and the quite poor.

Psychoanalytic theory is rather uncritically discussed and, surprisingly, attachment theory is not dealt with systematically (although it appears in passing in several chapters).

The brief chapter on cross-cultural comparisons usefully highlights the methodological concerns but does little to indicate why such comparisons can be informative in the study of causal mechanisms.

The encyclopaedia provides a useful introduction to what is known on several key aspects of child development but it cannot be recommended as an account of what is exciting and important in the best current science of child development, nor does it have much to say on social policy issues relating to childcare.

Sir Michael Rutter is professor of developmental psychopathology, Institute of Psychiatry, King's College London.