The fundamental tenet of contemporary sociobiology, namely the assumption of a single process of evolution involving the selection of genes, is critically examined. An alternative multiple-level, multiple-process model of evolution is presented which posits that the primary process that operates via selection upon the genes cannot account for certain kinds of biological phenomena, especially complex, learned, social behaviours. The primary process has evolved subsidiary evolutionary levels and processes that act to bridge the gap between genes and these complex behaviours. The (...) subsidiary levels are development, individual animal learning, and socioculture itself. It is argued that individual learning is pivotal to the derivation and biological analysis of culture. The differences between cultural and noncultural societies are stressed. It is concluded that such a multiple-level model of evolution can form the basis for reconciling opposing sides in the sociobiology debate. (shrink)

Many of the commentaries cohere around two major points of criticism. The first is that we have omitted discussion of the mechanisms that are assumed to operate at levels 2, 3, and 4.Campbell, Cloak, Dewsbury, Eckberg, Mundinger, Pulliam, Richerson & Boyd, Slobodkin, Simon, Williams, andWahlstenall make comments that bear on this point. The second point is that we have omitted discussion of the fact that "organisms change the environment by their activities" and thereby modify the selection pressures that act on (...) them. Apart from Lewontin, this point has been raised in different forms byBarkow, Chase, Hull, Perzigian, Ruyle, and less directly bySlobodkin. Stemming from these two basic omissions there is a third general criticism. Numerous commentators have pointed out that we have failed to discuss sufficiently either the extent or nature of the constraints that may or may not be operating on supraordinate evolutionary processes as a function of their nested relationships to subordinate evolutionary processes within our scheme. We start by acknowledging these three basic omissions. We agree that they exist and that they are serious. (shrink)