Archaeology and Cognitive Evolution
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BEHAVIORAL AND BRAIN SCIENCES (2002) 25, 389–438 Printed in the United States of America Archaeology and cognitive evolution Thomas Wynn Department of Anthropology, University of Colorado, Colorado Springs, CO 80933-7150 [email protected] Abstract: Archaeology can provide two bodies of information relevant to the understanding of the evolution of human cognition – the timing of developments, and the evolutionary context of these developments. The challenge is methodological. Archaeology must doc- ument attributes that have direct implications for underlying cognitive mechanisms. One example of such a cognitive archaeology is found in spatial cognition. The archaeological record documents an evolutionary sequence that begins with ape-equivalent spatial abil- ities 2.5 million years ago and ends with the appearance of modern abilities in the still remote past of 400,000 years ago. The timing of these developments reveals two major episodes in the evolution in spatial ability, one, 1.5 million years ago and the other, one million years later. The two episodes of development in spatial cognition had very different evolutionary contexts. The first was associated with the shift to an open country adaptive niche that occurred early in the time range of Homo erectus. The second was associated with no clear adaptive shift, though it does appear to have coincided with the invasion of more hostile environments and the appearance of sys- tematic hunting of large mammals. Neither, however, occurred in a context of modern hunting and gathering. Keywords: Archaeology, evolution, Homo erectus, spatial cognition, symmetry 1. Introduction man,” and the recent discovery of 400,000-year-old spears at Schoeningen (Thieme 1997) are unique and wonderfully This article has two goals. The first is to make a case for the informative, but they are atypical. The archaeological rec- relevance of archaeological contributions to studies of the ord boasts relatively few such treasures. Instead it consists evolution of cognition. The second is to provide an example largely of more incomplete and mundane traces that allow of one such contribution, a reconstruction of aspects of archaeologists to reconstruct some of what occurred in the early hominid spatial cognition based on an analysis of arti- past. The primary methodological task of the archaeologist factual symmetries. Assuming that human evolution is rel- is this reconstruction – translating traces into actions – and evant to understanding the human condition (an intellec- archaeology has developed a large body of concepts and tual position that is at the core of biological, if not yet techniques for doing this. We are very good at reconstruct- psychological, approaches to behavior), then archaeology ing diet from garbage, and social/political systems from the can supply two important bodies of evidence: (1) actual tim- size, character, and location of settlements. Can there be an ing of developments, and (2) the evolutionary context of archaeology of cognition? This is in reality a two-part ques- these developments. The challenge is not epistemological; tion. First, can traces of action inform us reliably about any archaeology can and does supply these things to the study aspect of cognition, and second, if so, can archaeologists of human evolution in general. The challenge is method- overcome some rather serious methodological roadblocks ological. How can archaeology inform us about the evolu- inherent to the archaeological record of such traces? tion of mind? (See Gowlett 1979; Holloway 1969; Parker & One way that psychologists learn about the mind is by ob- Gibson 1979 for seminal contributions in the same vein.) serving the actions of individuals in controlled laboratory Archaeology is a set of methods for reconstructing past settings or in natural situations. Sometimes these actions action from traces that exist in the present. These traces in- leave tangible traces that become the focus of the analysis. clude objects made or modified by people in the past – Children’s drawing is one example; block shuffling tests are tools, houses, ornaments, and so on – but also less tidy pat- another. The methodological task of the psychologist is to terns like garbage and refuse of all kinds and evidence of translate the tangible results into meaningful characteriza- past landscapes (through analysis of soils, pollen, faunal re- tions of the mind that produced them. Of course, psycholo- mains, etc.). Because some traces survive the ravages of gists can also talk to their subjects, but in principle, psy- time better than others, the archaeological record is a bi- chology can and does analyze the traces of action. An ased and nonrandom sample of past action. Stone tools, for archaeologist trying to do the same faces some additional example, survive well but wooden tools do not. Also, some environments preserve traces better than others. Tropical en- vironments are poor preservers, but cold, dry, arctic envi- ronments are good preservers. Archaeology is an observa- thomas wynn is Professor of Anthropology at the Uni- versity of Colorado, Colorado Springs. He was one of tional discipline. Unlike laboratory scientists, archaeologists the first archaeologists to make explicit use of psycho- cannot duplicate events, and unlike ethologists, archaeolo- logical concepts in the interpretation of the archaeolog- gists cannot depend on obtaining corroborating observa- ical record, and has published extensively on the cogni- tions, though we certainly hope for them. There is a real el- tive abilities of early hominids. ement of serendipity in archaeology. Pompeii, the “Ice Downloaded© 2002 from https:/www.cambridge.org/coreCambridge University Press. University 0140-525X/02 of Colorado $12.50Colorado Springs, Kraemer Family Library, on 11 May 2017 at 16:57:38, subject to the Cambridge Core terms389 of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0140525X02450078 Wynn: Archaeology and cognitive evolution hurdles. To make a convincing argument in cognitive ar- of evolution, an approach not focused on descriptions of in- chaeology, one must be able to identify specific features of dividual antecedents, but one focused on long term pat- the archaeological record that can inform about cognition in terns of change. Even though poor in detail, the archaeo- a valid and reliable way. This is the crux of the matter. Un- logical record is very long, providing a quasi-continuous fortunately, the disciplines of archaeology and psychology record of products of action that spans two million years. have never shared much in the way of theory and method- Archaeologists can use this record to identify patterns of ology. For an archaeologist to make a compelling case, he or cognitive evolution that provide insights into questions of she must not simply refer to a few selected psychological re- modern cognitive science. What follows is an example of this sults. There must also be some understanding of the theo- approach. The focus is on spatial cognition (generally con- retical and methodological context of the research. With this sidered, including shape recognition and image manipula- in hand, the archaeologist can define a set of attributes that tion). The evidence will consist of artifactual symmetry. can be applied to the archaeological record. This definitional step is indispensable. On the one hand, it is very unlikely that variables taken directly from the psychological literature 2. The archaeological record of artifactual could be applied to archaeological remains. On the other symmetry hand, the traditional categories of archaeology are inappro- priate, a point that bears emphasis. During the last century This article surveys the evolution of artifactual symmetry and a half archaeology has developed a large set of categories for three reasons. First, symmetry is a pattern and a con- for the description of archaeological remains. Some of these cept that is recognized by everyone, which reduces the re- categories are based on presumed function (e.g., ground quirement for definition (but does not eliminate it entirely). stone axe or temple complex), some on presumed usefulness Second, symmetry has been incorporated into many schemes in temporal ordering (e.g., Iron Age), some on social com- of spatial cognitive development, and also into theories of plexity (e.g., “Classic” Mesoamerica), and so on. None, to my perception, so that it provides a direct way to articulate the knowledge, has ever been defined with cognition in mind, archaeological record with the cognitive science literature. and it would be misleading to use them as such (e.g., to ar- Finally, it is amenable to visual presentation. gue that Iron Age people were cognitively different from There are several different patterns to which we apply Stone Age people). The cognitive archaeologist must avoid the term symmetry. The most familiar is reflectional sym- using these traditional categories and approach the archae- metry, also known as bilateral or mirror symmetry. Here, ological record from the perspective of psychological theo- one half of a pattern is duplicated and reversed on the op- ries and methods. posite side. Implicit in the pattern is a central line, usually Even after careful definition, archaeology faces a num- vertical, that divides the pattern into reflected versions of ber of roadblocks peculiar to its data. The first is preserva- one another. Bilateral symmetry is “natural” in the sense tion. Not only does preservation produce a biased record, that we see this pattern in the natural world of plants and it also presents a sliding scale of resolution. The farther back animals. A second symmetry is radial symmetry, in which a in time we look, the worse the record. There is less pre- pattern repeats not across a line, but continuously around a served, and there are fewer examples of what is preserved. point. Similar to radial symmetry is rotational symmetry, in This alone gives the archaeological record a misleadingly which a pattern is not reflected across a line, but rotated progressive appearance; 10,000-year-old remains appear around a point; here the pattern is not reversed or inverted.