Linking Studies of the Individual with Models of Aggregate Behaviour: An Empirical Example

Abstract

There have been few attempts to resolve the numerous studies of individuals' behaviour, perceptions and knowledge of environments, on the one hand, and of aggregate behaviour in space, on the other. This paper attempts to fuse these different scales by using mental models of the retail environment as the input for models of aggregate behaviour in order to suggest ways of conceptualizing behaviour at the aggregate level that would be both behaviourally more realistic and descriptively more accurate. These models are then tested against observed patterns of behaviour, but are found to fail satisfactorily to resolve the problems of producing accurate descriptions and realistic behavioural models of aggregate behaviour. In particular, a model of centre choice proved descriptively more powerful than one of choice of individual shops, but characteristics of centres as such were not revealed as important determinants of choice at the level of the individual and his or her conceptualization of the food retailing environment. Finally, the theoretical and practical implications of the research are discussed. ALTHOUGH there are now numerous studies of individuals' behaviour, perceptions and knowledge of reality and numerous studies of aggregate patterns of behaviour in space, attempts to fuse these two approaches are notable by their absence. This would also seem true of the social sciences in general; only Green (1964) would seem to have explicitly tackled the problems of aggregating from the individual to the group, albeit in a rather restricted context. It is clear that these problems are serious. For example, individuals may differ in the structure, dimensionality and geometry of their cognitive models of reality which serve as a basis for choice and this would pose serious problems in attempting to combine such people into groups that were homogeneous with respect to their choice process. Moreover, the problems of collecting such data for a large random sample of some population are formidable. A rather less ambitious procedure of combining information on individuals with models of aggregate behaviour is adopted here. Individual behaviour, in the context of aggregate models of spatial systems, is generally handled in one of two ways. One of these has been to make a series of assumptions about individual knowledge, motivations and decision processes, usually assumed to be identical for all individuals, drawing on normative micro-economic theories as a source of such assumptions (which guarantees to nullify the empirical validity of such assumptions in a spatial context). For example, such assumptions underpin normative industrial location theories (Isard, 1956) and the central place theories of Losch (1954) and Christaller (1966). In the context of the aims of these theories, to derive equilibrium states for various sectors of the spatial economic system, such assumptions are necessary. Nevertheless, it remains the case that they lack empirical validity and have been rightly criticized on this score. This glaring lack of correspondence between the behaviour of Economic Man (as these assumptions are conventionally personified) and Actual Man has served as a stimulus to much research on individuals' perceptions and knowledge of various environments (Downs, 1970; Harrison and Sarre, 1971; Sarre, 1972).