S chjelderupp-Ebbe, who discovered and described pecking orders in hens ( 1922), laid the foundations for a vast body of research on inequality of individuals. Thirty years later, when early ethology rediscovered that behavior could be a product of natural selection, it was a small step to surmise that this principle also could apply to social structures and social sorting processes in humans.
Continuing research in this area developed quite different concepts. These concepts range from dominance and hierarchies to visual regard, status, and rank orders. Application of these concepts to observable behavior, however, can be difficult, because of some problems inherent in the definition of these concepts. Dyadic dominance, for instance, seems to be a relationship feature that can not be extended to hierarchies, because the members of groups employ a variety of strategies different from those commonly used in dyadic interactions. In contrast to dominance, therefore, social status describes power relations on a group level.
Although we can observe tactics for attaining social status reliably and repeatedly in groups, explanations for their existence are manifold. The proximate level, i.e. explanation in terms of the immediate causation and function of a behavior, and the ultimate level, i.e. explanation in terms of inclusive fitness, are best looked at separately in such an endeavor.