Agricultural production is increasingly combined with other economic and noneconomic activities. This leads to complex interactions taking place within rural systems. The recent policy shift towards a more holistic approach in terms of integrated and sustainable models of rural development emphasises these developments. In this context the role of 'noneconomic' determinants of behaviour is placed to the fore. The orthodox economic approach stresses (almost) instantaneous adjustments to prices and other 'economic' factors. This is at odds with idealised images of the 'efficient' market, which is characterised by a great deal of uncertainty. In such a volatile environment, routines-based behaviour, such as following institutional rules and/or socially acceptable types of behaviour, usually described in term of 'social capital', is advantageous and creates a more stable environment. The stable environment is a pre-requisite for workability of the purely 'economic' arrangements. This intuitive argument is developed using a simple mathematical model, incorporating 'social' and 'economic' factors. The social dimension enhances the impact of economic factors, slowing the speed of adjustment to the equilibrium state. Some conditions under which the social and institutional infrastructure are beneficial or detrimental for economic development are outlined. An important by-product of our model is the conclusion that social and economic factors are closely entangled and their separate influences are purely analytical devices. Ignoring this entanglement may lead to serious biases in quantitative analysis. Some examples of these potential pitfalls are presented.