Working Memory and the Evolution of Modern Thinking

ORGANIZER’S STATEMENT: The last two decades have witnessed an intense and often contentious debate in paleoanthropology concerning the evolution of modern humans and the modern human mind. Perhaps the most remarkable feature of this debate has been its naivety concerning the modern mind itself. Instead of incorporating the great strides made by recent cognitive science in understanding the nature of the brain and cognition, paleoanthropology (with the exception of a few paleoneurologists) has eschewed this literature almost entirely, preferring instead to fall back on vague, ill-defined terms from the common lexicon (e.g. ‘abstract’, ‘complex’, and ‘symbolic’) or, equally as often, on concepts drawn from the anthropological literature most connected to cognitive science – linguistics. However, when psychologists and cognitive scientists themselves think and write about the modern mind, language is not the only cognitive ability to receive attention. Indeed, it is only one of a number of cognitive abilities considered to be essential to modern thinking. Among these is a set of abilities known as executive functions, which encompass the abilities to plan and strategize. More controversially, recent research in cognitive science has linked executive reasoning ability to Alan Baddeley’s concept of working memory, which is the ability to hold information in attention and process it. Executive functions in general, and working memory in particular have been the focus of voluminous research in cognitive science. Research has established that working memory capacity varies in (but not between) modern populations, and that this variability may be under comparatively simple genetic control. As such it makes a good candidate for a recent evolutionary development.

Anthropologist Thomas Wynn and Psychologist Frederick Coolidge organized this Wenner-Gren international symposium in order to investigate the hypothesis that working memory capacity evolved over the course of human evolution, and that a final enhancement of working memory capacity occurred in the relatively recent past, enabling the rapid expansion of modern humans at the expense of more archaic forms. For the symposium to be a success it was necessary to bring together two groups of scholars who do not normally interact: cognitive scientists who study working memory and paleoanthropologists who study human evolution. The two groups came together at the Forteleza do Guincho in Cascais, Portugal, between March 7 and March 14, 2008.

Randy Engle and Lyn Wadley led off the formal discussions with, respectively, an account of the status of working memory in psychological research, and a provocative consideration of ways to document working memory in archaeological traces from the Middle and Later Stone Age of South Africa. Each grounded his and her discussions in experimental and/or field data, and in so doing provided an empirical imperative that helped orient all of the subsequent discussions. In the second session linguist Eric Reuland, psychologist Matt Rossano, and archaeologist Iain Davidson focused on the possible links between working memory, symbolic thinking, and language, and introduced the significance of transoceanic colonization for documenting working memory. In the third session, papers by Miriam Haidle, Philip Barnard, and Philip Beaman explored alternative cognitive models of decision making, and extended the evolutionary scope of the discussion to include early hominins. The fourth session injected paleoneurology and life history into the discussion via papers by Emiliano Bruner, Francisco Aboitiz, and April Nowell, and the fifth session considered alternative models for understanding the evolution of cognition through papers by Anna Belfer-Cohen, Stanley Ambrose, and Manuel Martin-Loeches. After the free day, philosopher Rex Welshon made a gallant attempt at synthesis, initiating a general discussion that highlighted points of disagreement and possible avenues for resolution. The participants then divided into three groups, each of which focused on a particular point in hominin evolution, addressing the general question of what, if anything, could be concluded about the working memory capacity of the hominin in question.

Several overarching questions emerged from the discussions. Not surprisingly, the nature of working memory itself was a prime concern. By the end the participants had sorted into two basic camps. One preferred to view working memory as a limited capacity buffer (attention, in essence) that can access a number of more specific, perceptually linked stores of information (visuospatial, phonological, auditory, etc.), while the other preferred to grant phonological storage primacy in its ability to store and manipulate words and symbols. The second major topic of discussion addressed how one might recognize or evaluate working memory capacity in the archaeological record. Interestingly the usual list of ‘modern’ patterns favored by some archaeologists (blades, large mammal hunting, personal ornaments, and so on) did not fare particularly well as markers for working memory. Instead, less ballyhooed examples such as hafting, the use of remotely operated traps, and colonization of oceanic islands, received most discussion, attesting the value of using an explicit cognitive theory to generate appropriate test cases.

Finally, timing the appearance of modern working memory capacity proved less problematic to the cognitive scientists than to the paleoanthropologists. Although the group reached no consensus as to a specific timeline, the majority of the group, both cognitive scientists and anthropologists, appeared comfortable with a timing that granted modern working memory capacity to early Homo sapiens.

Current Anthropology supplement on the UCP website

Wenner-Gren Symposium #139