Darwinism and cultural change

Abstract

Evolutionary models of cultural change have acquired an important role in attempts to explain the course of human evolution, especially our specialization in knowledge-gathering and intelligent control of environments. In both biological and cultural change, different patterns of explanation become relevant at different 'grains' of analysis and in contexts associated with different explanatory targets. Existing treatments of the evolutionary approach to culture, both positive and negative, underestimate the importance of these distinctions. Close attention to grain of analysis motivates distinctions between three possible modes of cultural evolution, each associated with different empirical assumptions and explanatory roles.

Figure 1.

Redrawn from Willi Hennig's Phylogenetic systematics. Copyright © 1979 by the Board of Trustees of the University of Illinois. Used with permission of the authors and the University of Illinois Press.

Figure 2.

Three views of an adaptive landscape, representing fitness as a function of two phenotypic variables. (a) From a zoomed-out perspective, many peaks are visible and only a few are occupied. Dots mark the occupation of a peak by a species. Contingencies of history have a strong effect on which areas are explored. (b) Zooming in, a species becomes a blurred area, and selection will lead to species occupying local peaks. (c) Zooming in even further, individual organisms can be seen. Change at this level is affected by the details of population genetics and includes non-adaptive factors.

Figure 3.

A process in which successful variants proliferate and provide independent sites for further innovation (a) is compatible with several lower level patterns (b) seen when a more zoomed-in perspective is taken.

Figure 4.

Three scales are shown at once. At the micro-evolutionary scale, change may have a Darwinian form with parent–offspring relations between instances of cultural variants, or the form of a network without parent–offspring lineages. Both are compatible with a pattern at the meso-scale in which successful variants proliferate and provide many independent platforms for further innovation. (See the text for more detail and some qualification of this claim.) A collection of cultural lineages may have a tree-like shape whether or not a ‘chain of fountains’ pattern occurs at the meso-level and whether or not parent–offspring relations are visible at the micro-level.