Does distance matter for technology spillovers?

How does knowledge, i.e. innovations, diffuse over space? Traditional diffusion theory does not consider this question, but instead focuses on diffusion over time. After some early publications such as Gerschenkron (1962) and Abramovitz (1979), research on technology diffusion over countries was deepened during the 1980s. This literature became known as technology gap literature. Main argument of this literature is that technology is regarded to spread to a country due to specific characteristics of that country. The countries between which spillover of knowledge takes place, need not necessarily be geographically close to each other, therefore geographic proximity does not play a substantive role in this literature. The so called spatial factors like agglomeration economies and growth poles as used by geographers were not addressed in this set of theories. Only the geographic stream of researchers used these concepts. Within the field of geography, diffusion is regarded as a purely geographical process and space is a central concept. Scale effects and proximity effects are considered to be the main vehicles which carry the spread of economic activity. This paper develops a theoretical model which tries to explain the development of growth poles, by allowing knowledge spillovers to take place across regions. The aim of this paper is to integrate both streams in the literature (technology gap and geography). The lack of space as an explaining factor in technology gap models is addressed in this paper by extending a simple technology gap model with the concept of geographical distance. The geographical distance towards another region partly determines the amount of spillovers one region receives from another. This paper extends the 'traditional' technology gap models also in a second way, by considering more than two regions. Three geographical spheres are considered, namely a lattice, a column and a globe. Depending on the geographical sphere that is used, 19, 21 or 32 regions are considered. Several theoretical experiments are performed on the different geographical spheres to illustrate the behavior of the model. Economic growth, evolutionary theory, regional growth theory, economic integration