While I was in Cambridge, one of the things I got interested in was cognitive archaeology– a sub-branch of archaeology that uses physical and geographical artifacts to reconstruct the mental worlds of ancient peoples. One of the big figures in the field, Colin Renfrew, is a professor at Cambridge, and I was lucky enough to spend some time with him; when I visited Oxford I spent a little time with one of his former students, a brilliant guy named Lambros Malafouris. The field interests me for two reasons: first, it might be able to provide additional evidence to test arguments about the relationship between cognition and new technolog; and second, it might offer some design clues for creating contemplative objects. It strikes me that there are certain pieces of material culture that tend to reappear in contemplative and meditative practices– bells for example– and qualities that are valued in contemplative spaces, and I want to get a better sense of how old these might be.

So I was interested to see an article by Lyn Wadley and colleagues at the University of the Witwatersrand in South Africa, on multitasking and the making of stone tools:

Compound adhesives made from red ochre mixed with plant gum were used in the Middle Stone Age (MSA), South Africa. Replications reported here suggest that early artisans did not merely color their glues red; they deliberately effected physical transformations involving chemical changes from acidic to less acidic pH, dehydration of the adhesive near wood fires, and changes to mechanical workability and electrostatic forces. Some of the steps required for making compound adhesive seem impossible without multitasking and abstract thought. This ability suggests overlap between the cognitive abilities of modern people and people in the MSA. Our multidisciplinary analysis provides a new way to recognize complex cognition in the MSA without necessarily invoking the concept of symbolism….

People today have a capacity for novel, sustained multilevel operations; this ability may have arisen from neural connectivity in part of the prefrontal cortex (1). The capacity may be recognizable in some technologies, and we use compound adhesive manufacture as our example.

Here's how they conducted the experiment:

To explore first the effect of using ochre as a loading agent in plant gum glues and, second, the complexity of thought processes involved in compound adhesive manufacture, we replicated hafted tools by using only products and methods that would have been available in the MSA. The choice of natural products means that our methodology differs from laboratory-based experiments in which iron oxides and oxyhydroxides are synthetically produced with controlled pH, ionic strength, and temperature. Natural products and wood fires incorporate variables that are disastrous by laboratory standards, but ancient artisans were obliged to deal with these…. Such variables imply that ancient adhesives may not have been made by using standard recipes, but that on-the-spot adaptations, requiring cognitive fluidity, were necessary.

Part of what I love about this is that it's a little reminder of how manual labor is anything but divorced from thinking and cognition. We too easily draw a boundary between working with your hands, and working with materials, and services or "symbolic analysis" or whatever economists like to talk about. But as anyone who bakes or works with wood or metal knows, materials require attention and experience to master; and a lot of that experience and mastery consists of learning how to deal with the irregularities and eccentricities of your material and processes.

So what did their experiments teach them?

Hunters' lives depend on reliable weapons. This dependency would have been a powerful incentive in the past to create trustworthy adhesives for composite weapons… [and my the MSA] people were competent chemists, alchemists, and pyrotechnologists. We propose that these artisans were exceedingly skilled; they understood the properties of their adhesive ingredients, and they were able to manipulate them knowingly….

[O]ur familiarity with compound adhesive manufacture from natural ingredients helps us make interpretations about the type of cognition that the early artisans must have had. Some birds and wasps also create compound adhesives, but they do so instinctively with simply coded operational sequences, “cognigrams,” in which the distance between problem and solution is far smaller than that demonstrated by the human action of making a composite hunting weapon (35). One obvious difference in human manufacture of compound glue is the use of pyrotechnology. Temperature control depends on understanding wood types, their moisture contents, and their propensity to form long-lasting coals. Vigilance is essential because our adhesives burned, or boiled to form air bubbles, when they were too close to the fire. Overdehydration caused loss of cohesiveness, whereas boiling adhesive created weakness.

The glue maker needs to pay careful attention to the condition of ingredients before and during the procedure and must be able to switch attention between aspects of the methodology. To hold many courses of action in the mind involves multitasking, which is one trait of modern human minds (2), notwithstanding that even today, some people find multilevel operations difficult. On-the-spot compensations have to be made for the capricious character of natural ingredients. Viscosity of Acacia gums varies, demanding different quantities of loading agent. Powdered ochres are also inconsistent: even when they are visually similar because of red staining by minute quantities of hematite, which has pervasive pigmenting capacity (14), they can be dissimilar with respect to Fe and Si percentages, particle size, pH, and ZP. Thus, ongoing evaluation and control of texture, viscosity, plasticity, and temperature is required; no set recipe or routine can guarantee a satisfactory adhesive product.

Mental flexibility is not the only complex attribute implied by our experiments. Artisans living in the MSA must have been able to think in abstract terms about properties of plant gums and natural iron products, even though they lacked empirical means for gauging them. Qualities of gum, such as wet, sticky, and viscous, were mentally abstracted, and these meanings counterpoised against ochre properties, such as dry, loose, and dehydrating. Simultaneously, the artisan had to think about the correct position for placing stone inserts on the hafts. Successful mental rotation requires advanced working memory capacity (36) and, in turn, complex cognition. Capacity for multilevel operations, abstract thought, and mental rotation are all required for the process of compound adhesive manufacture. Although fully modern behavior is presently recognizable relatively late in the MSA (37), the circumstantial evidence provided here implies that people who made compound adhesives in the MSA shared at least some advanced behaviors with their modern successors.

I think it's important, though, to distinguish the kind of "multitasking" they describe here from the multitasking that we consider problematic today.

For Wadley et al, multitasking is the ability to "hold many courses of action in the mind;" involves the capacity for abstract thinking, and the capacity to switch attention between different objects or parts of a process. This sort of multitasking seems to be one of the things that sets humans apart from animals (even if its a difference of how capable we are, or how many different things we can juggle, rather than whether we're the only species capable of doing anything like this).

But this is quite different, I think, from the sort of multitasking that involves trying to do several entirely separate things at once. As I write, I have a couple books and my journal open on my desk, and a couple online articles; I can move between them as I look up one thing and then another, check citations, look up references, and make sense what I'm reading. Perhaps there are several different kinds of mental operations at work here, but what's important is that they're all aimed at a single purpose: understanding the history of multitasking.

That's very different from having a couple books on different subjects, while also chatting with a high school friend on Facebook, and answering my daugther's questions about whether she can watch a movie (she's home sick today). These are all different things, and don't add up to a single grand intellectual challenge. We call it multitasking, but it would be more accurate (as psychologists will tell you) to call it something else: switch-tasking.

This cognitive resources required in switch-tasking are vastly different from the resources required for ancient (or modern) multitasking; and I think that at the personal level, they're experienced in very different ways. Mixing the gum and ochre, watching it heat, stirring it, getting a feel for how it's cooking and what you need to do to it next, would create something closer to a flow experience, not the sense of being pulled in several different directions that you get when switch-tasking.