example in Uganda (Minority Rights Group International, 1997) and Zambia (Posner, 2004). The question of regional, or spatial, inequality has become increasingly important over recent years, and has begun to attract significant interest among scholars and policy-makers. In most developing countries, there is a sense that regional inequalities within countries in terms of economic activities and social indicators are rising (Kanbur & Venables, 2005).

Stewart (2000; 2002) does not explicitly specify what kind of cultural identifier is most relevant for conflict, but proposes that one can often use regional data to proxy differences among ethnicities since regional location tends to coincide with ethnic or language divisions (Stewart, 2000: 247, 255). Moreover, data on group inequalities are far more accessible for regional than ethnic or religious groups, since questions concerning ethnic affiliation are often dropped or at least not published in national surveys and censuses. However, regional groups may also be important in their own right: In a natural field experiment among the Chewa and Tumbuka groups in Zambia Posner (2004: 543) found that the regional cohesion seemed to be stronger than the claims of ethnic affiliation:<sup>4</sup> ‘Whether or not a cleavage matters would seem to depend not at all on the material from which it is built. That material can be as sturdy as the traits, customs, norms, and practices that a professional ethnographer might identify as flimsy as an arbitrary boundary drawn by an uninformed colonial officer’.

In general, why should horizontal inequalities be relevant for conflict? The most obvious answer to this question relates to the effect of collective grievances. Members of disadvantaged groups are likely to feel frustration and antagonism, especially when their relative deprivation is the result of actual exploitation and discrimination, which is apparently often the case (for example in Senegal and Uganda). Indeed, Horowitz (2000) holds that in most cases conflicts are initiated by the less privileged groups. Despite the intuitive logic of this argument, one cannot, however, assume that it is only resentment on the part of the disadvantaged groups that may cause political instability. The privileged groups may also attack the unprivileged, fearing that the latter may demand more resources and political power (Stweart, 2000). According to Tadjoeddin (2003) this is actually what happened in Indonesia, where conflicts often stem from confrontations between the central authorities and several _richer_ provinces (in terms of natural resources) whose people are upset by the center’s use of their region’s wealth to subsidize poorer regions.

When people in rich regions perceive the central government’s policies as unfair and authoritarian, they may see greater autonomy, or even secession, as a better alternative than the status quo. As Aristotle said, ‘Inferiors revolt in order that they may be equal, and equals that they may be superior’ (quoted in Sigelman & Simpson, 1977: 106). For example, privileged groups that are geographically concentrated may demand independence, such as the Basques in Spain. In line with this logic, the initiative to conflict may come from the richest and most privileged groups as well as the poorest and most deprived groups. Both types of reactions point to the conclusion that a society of high horizontal inequalities has a higher risk of civil war than societies without such inequalities. It is easier to maintain group cohesiveness and motivation for rebellion if the elite can draw on ethnic, religious, or regional differences to construct a well-

> 4 Nevertheless, it should not be ignored that some of the worst forms of ethnic attacks have been non-regional, such as the conflict between Hutus and Tutsis in Rwanda.

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