Beyond the fractal frontier

A new journal has to have some very good reasons to gain our attention when our library budgets are tight and when we have already got enough to read. Nonlinear Dynamics, Psychology and Life Sciences can claim to do some attractive things. Primarily, it is interdisciplinary in a new area that needs a lot of work and where a lot of interesting work is going on. It is not the result of some bunch of specialists creating themselves an artificial niche for their esoteric work, but of social scientists picking up on the enthusiasm of recent advances in complexity theories. This is a new, thorough, interdisciplinary area, with a lot of promise.

The butterfly in the Amazon rain forest flapping its wings and influencing the weather in Britain is one of the trademarks of chaos theory, that some effects are non-linear and unpredictably related to their causes. Yet chaotic systems, despite their name, have regularities. For example, the beating of our heart depends on the chaotic organisation of twitching muscles, yet it beats pretty regularly.

Chaos is just one of the recently developed mathematical tools for understanding complexity. Fractals, familiar to everyone from colourful pictures of the Mandelbrot set, represent complex patterns with simple underlying structure. Emergence, another idea, represents simple overall aspects of the behaviour of complex systems, such as our - sometimes! - clear thinking that emerges out of the random behaviour of our brains' electrochemical activity. The journal takes non-linear dynamics to include cellular automata, genetic algorithms, neural networks and so on. It wants to build bridges between these theoretically successful areas, particularly with psychology and the life sciences.

These ideas have been tremendously successful in the physical sciences, and many of them seem to relate very closely to human behaviour. Economic systems behave chaotically; organisations adapt; people think. This journal has covered all of these examples in very interesting papers.

A good journal can be better than a book, because it brings the field alive and stays abreast of developments. Moreover, as you get interested in the field, you can write articles yourself and contribute. This journal has come at an exciting time: the work is, in most cases, simple enough for good masters students to replicate and get useful projects out of, yet challenging enough for research students to question and go beyond.

Almost all of the articles published in the journal treat mathematical devices as descriptions of phenomena rather than as explanations. There is a huge difference between being able to pull a formula out of a hat and get nice results, and having a reasoned explanation of the phenomenon in question. In one case, the mathematics is no more than a metaphor; in the other it provides a lever to advance knowledge and to inform effective ways for controlling or influencing systems. If the "system" is a serial murderer - to take a recent example published in the journal - knowing how to describe intervals between murders is one thing; knowing how to influence the interval between murders so as to increase it, would be something much better.

Because the field is new, the articles are easy to read and understand, so they will be good for PhD students. There are lots of pleasing nuggets, and perhaps some fool's gold, too. Social scientists will want to dig deeper into a very productive seam, and mathematicians will want to make the field far more rigorous. They may write the philosophy of science articles that the journal welcomes but has not published yet.

Nonlinear Dynamics, Psychology and Life Sciences is the journal of the Society for Chaos Theory in Psychology and Life Sciences. Membership of the society gives you a one year's subscription to the journal. A typical issue of the journal has four substantial articles of about 20 pages each, and other matter such as book reviews. More can be found out from the internet site for the society, which includes details of the journal, and is at http://www.vanderbilt.edu/AnS/ psychology/cogsci/chaos Harold Thimbleby is professor of computing research, Middlesex University.