PROFESSOR NIGEL GILBERT IT AND COMMUNICATIONS FBCS FREng DIRECTOR, CENTRE FOR RESEARCH ON SIMULATION IN THE SOCIAL SCIENCES, UNIVERSITY OF SURREY Modelling societies It is now possible to simulate on a computer the complex interactions between people, organisations and technology, and study how they evolve over time. Such ‘social simulation’ is being used to conduct experiments and test out theories that would be difficult, or impossible, to test in the real world. Nigel Gilbert explains how it all works and discusses some of the research that is currently underway. Introduction One way of exploring these issues dynamics are usually complex, that is growing in importance is to build meaning that at best only qualitative We know that collaborations between computer models that simulate the and coarse-grained predictions are universities and companies are situations in which we are interested. possible. The same applies to some important for innovation, but what kinds Researchers can then experiment with physical phenomena, such as of collaborations are most effective? the models, which is of course easier, turbulence. Nevertheless, modelling is How can the conflicting demands made quicker and involves fewer ethical and useful. It can allow one to gain a much for the water in Europe’s river basins by practical problems than experimenting deeper understanding of the factors individuals, farmers, water utilities, the with societies. that are important in a social setting, environment and transport be However, the simulations used by which policy ‘levers’ can make a reconciled? What is the most effective social scientists are fundamentally difference to outcomes and which are way of persuading farmers to manage different from most of those used in unlikely to do so. their farms in an environmentally friendly engineering. If you design a simulation In this article, I will describe briefly a way? How do people manage their of airflow over a wingspan, for few of the areas where social simulation money so that they have enough to get example, you expect that you will be has been used. It is still a very recent by, despite varying calls on their able to make accurate predictions of approach (most of the work has been savings? parameters such as drag from the done within the last ten years) and one These very different questions have model. With models of human that is developing rapidly. Consequently, one important factor in common. They institutions, however, prediction is a much of its potential is still to be all involve studying complex interactions probably unattainable goal (although exploited, especially in linking academic between people, organisations (farmers, some people are still trying to develop research using simulation to practical universities, utility companies, and so reliable models of stock exchange policy-making. on) and technology over time. ingenia price changes). This is because social 35 IT AND COMMUNICATIONS Representing complex human interactions Computer models are natural Simulation with computer models has a candidates for social science theories … long history in engineering and the physical sciences, where it is used as a way of understanding and predicting the behaviour of anything from atoms language is good at describing modelling many different kinds of to bridges. However, until recently it complicated and time-dependent element together with their interactions was thought that computational relationships, it is rather difficult to within the same program (using ‘object- modelling had little to contribute to the make these descriptions precise. In oriented’ programming); and are pre- social sciences, except in a few some other sciences, particularly eminent in representing processes, ie specialised areas such as macro- physics, mathematics is the favoured changes that happen over time. economic modelling. medium for theories. However, Computer models are thus natural The breakthrough came in the early mathematics tends to have difficulty candidates for social science theories. 1990s when artificial intelligence dealing with the dynamics of complex It may seem strange to think of a researchers showed that computer systems involving interactions between computer program as a theory, but that programs called ‘multi-agent systems’ many heterogeneous elements. This of is how they can be used: like any could be written to represent individual course is exactly what societies are, theory, they can tell a story about how people or organisations and their and explains why mathematics has the world works. interactions. Today, the field of social never achieved the same place in the For example, a computer program, simulation is expanding rapidly social sciences as it has in physics. given a ‘pension’ each month as throughout the world, and has its own – income for a simulated retired person electronic – journal, the Journal of and some pre-specified needs for food, Computer models Artificial Societies and Social Simulation housing costs, holidays, consumer (see Further Reading). In contrast, computer programs are durables and so on, could make Social scientists often write their precise (they have to be if they are to decisions about what to buy and when, theories in textual form. While ordinary run on a computer); are capable of according to built-in rules. The rules that make up the program might be a theory of how people make budgeting decisions. The theory can be tested and refined against examples of what real people have done with their money. The program can be used as the basis … until recently it was for experiments to understand the relative influence on personal budgeting thought that of learning from trial and error, of rational calculation and of imitation of computational modelling the spending patterns of others. had little to contribute to Edmund Chattoe and I did just this in recent research funded by the the social sciences … Economic and Social Research Council. A budgeting model was constructed based on what people who had recently retired said about the way in which they managed their money. The interviews showed that almost all households divide their expenditure into three parts that are managed differently. Bills such as those for a mortgage and electricity ingenia can often be predicted exactly up to a year in advance and are often paid ‘automatically’, not even being regarded as part of disposable income. 36 IT AND COMMUNICATIONS Social scientists are trying to understand the consequences for innovation of the increasing collaboration The that seems to be developing in answers you get from biotechnology … the experiments are only as good as the models … but they are often still much better than nothing … Expenditure of the second type can obvious, it is not adequately reflected in experiments are only as good as the be made more or less regular by habit existing economic theories of consumer models – if the model is flawed, so will (or other mechanisms of monitoring and behaviour, and it adds a significant be the experimental results – but they control), so it is possible to budget degree of complication to the task of are often still much better than nothing. approximately for it, based on past keeping the household within budget. As part of the Common Agricultural experience. An example of expenditure We found that as a result, households Policy (CAP), there are schemes called of this kind is provided by the weekly arrived at rules of thumb to guide their ‘Agri-Environmental Measures’ that shopping trip, which always costs budgeting and often maintained these provide subsidies for farmers who agree about the same, provided the same rules over decades, even when there to farm in a more environmentally friendly sorts of things are bought. were marked changes in personal way. The European Union is funding the The third kind of expenditure involves circumstances. construction of a model that represents items that are large, unexpected or The model was used to explore the the decisions of farmers when given the unique and these will be financed out of effectiveness of some of these option of signing a contract that pays money that is deliberately kept separate, budgeting heuristics. One way in which them for farming in an environmentally for example, in a savings account. the model could now be taken forward friendly way. The decision process is Experiments with the computer model would be to use it as an educational modelled as a blend of rational showed the value of having two simulator for people just starting to calculation, imitation and influence from accounts, one for current expenditures manage their own money, or who find friends and neighbours, using theoretical and one for savings, in reducing the budgeting difficult. ideas from social psychology and effort involved in budgeting. sociology about decision-making and the The model also brought home the diffusion of ideas. This simulation will be fact that households can adjust either ‘What-if’ experiments useful to EU policymakers who need to or both their budget and their set of In the social sciences, experiments are design effective contract schemes and activities when there is a mismatch often impossible or unethical, because want to do ‘what-if’ trials with the model. between them. If there is not enough they would have to be done on people, There are similarities between this money to pay for a trip to the cinema or even on whole societies. Instead, and another area where the potential of for the family, they can stay in and experiments can be done on computer simulation is becoming recognised: the watch television. While this is fairly models. The answers you get from the modelling of consumer demand. Most ingenia 37 IT AND COMMUNICATIONS studies of why people buy particular consequences for innovation of the increasing number of people worldwide brands focus on the interaction between increasing ‘networking’ and are beginning to take an interest in the an individual’s attributes – their attitudes, collaboration that seems to be potential of this new use of simulation.