Volume 15, Number 2 Bulletin of the General Anthropology Division Fall , 2008

ated by the recognition that primate eco- Successful Teaching Tools and Brain Size logical and technological adaptations are socially learned, and that multiple inter- Cultivating the Teaching Technology and Human Brain acting causes and constraints will need Moment Evolution to be considered in any full explanation of human brain evolution. In short, tech- By Elizabeth Chin* By Dietrich Stout nology is social, and the early specula- Occidental College University College London tions of Darwin and Engels continue to eaching, for me, is fundamentally Mastery over nature began with look remarkably current. about facilitating an atmosphere the development of the hand, with Tin which students are able to labour…the development of labour The earliest direct evidence of homi- learn, and creating opportunities for all necessarily helped to bring the mem- nid technological activity, and thus social of us to broaden our understanding of bers of society closer together by in- interaction, comes from stone tools and what learning is and how it can be ac- creasing cases of mutual support and cut-marked bones dating back as much complished. Because my classroom is a joint activity, and by making clear the as 2.6 million years at Gona (Ethiopia). space in which learning is collaborative advantage of joint activity to each in- The ensuing ~2.4 million years of the Lower Paleolithic witnessed a technologi- and processual as opposed to authori- dividual. In short, men in the making cal progression from simple ‘Oldowan’ tarian and outcome oriented, students arrived at the point where they had stone chips to skillfully shaped something to say to each other—first often have to rethink many of their as- ‘Acheulean’ bifacial cutting tools, accom- labour, after it and then with it speech sumptions about knowledge and learn- panied by a nearly threefold increase in ing, teaching and education. I want stu- —these are the two most essential hominid brain size from the top end of dents to learn how to learn, to come away stimuli under the influence of which the ape range to the bottom end of the from their learning experiences with the the brain of the ape gradually modern human range. This coincidence ability to apply their problem-solving, changed into that of man. of two of the most striking trends in hu- man evolution certainly suggests a rela- Frederick Engels Teaching continued on page 5 tionship, but is it one of cause, conse- The Part Played by Labour in the quence, or mere corollary with other, Transition from Ape to Man 1883 In This Issue more fundamental factors? To address such questions, we need to know exactly ool-use and tool-making have long what it is we are trying to explain about Chin on Page 1 been seen as “prime movers” in the modern human brain. Teaching Strategies T a uniquely human evolutionary package linking bipedalism, dexterous The brain: what needs to be Stout on hands, articulate language, culture, and explained? Brain Development and Page 1 a large brain (Darwin 1871, Holloway Technology 1969, Washburn 1960). The 1980s and veryone knows that human brains 90s saw a major reappraisal of this or- Eare “big,” but what does this actu- Paleoanthropology Page 8 thodoxy, with influential “Machiavellian ally mean? Whales and elephants have Intelligence” (Byrne and Whiten 1988) absolutely larger brains and mice have Film and Video Page 11 and “Social Brain” (Dunbar 1998) hy- relatively larger brains, yet few people potheses explaining large brains as a re- want to conclude that these animals are Useful Ethnographies Page 14 sponse to the demands of group living more intelligent than us. Actually, the re- rather than ecological or technological lationship between brain and body pressures. In the past decade, however, changes systematically with size (is “al- this sharp distinction has been moder- Brain continued on page 2 Brain continued from page 1 in many studies to correlate with mam- shifts in developmental timing. On the lometric”), and this fact has been used malian social group size and/or complex- other hand, selection may sometimes to develop measures of brain size that ity. have acted more directly on particular do put humans on top. For example, brain functions, in which case one would Harry Jerison’s famous Encephalization Such allometric approaches provide expect a more “mosaic” pattern of spe- Quotient (EQ) compares observed brain a neat solution to the problem of com- cific structural, micro-structural and even size with expected brain size as predicted paring brains, but there may still be a molecular adaptations. It is likely that from an allometric (slope=0.67) regres- problem with simply factoring absolute both kinds of processes helped to shape sion of brain size on body size. Another size out of the equation. As Terrence the modern human brain. method is to compare the size of differ- Deacon (1997) has emphasized, larger ent structures within the brain, based on animals live in a larger world. Because In some respects the human brain is the idea that some parts of the brain are they tend to live longer and encounter just what you might expect from a large concerned mostly with bodily regulation more environmental variability, larger bodied, long-lived, omnivorous primate. (e.g. brainstem) while others are more animal have both the motive and the op- It is large in relation to other primate “cognitive” (e.g. neocortex). The clas- portunity to rely on flexible learned be- brains, has a relatively large neocortex, sic example of this is Robin Dunbar’s haviors instead of hard-wired instincts. takes a long time to develop, and sup- Neocortex Ratio, which has been found Larger brains must also be organized dif- ports some pretty complex socio-eco- ferently from small brains. Geometrically logical behaviors. Much the same might General increasing numbers of potential connec- be said of omnivorous pigs and bears in Anthropology tions and distances between neurons relation to their more specialized rela- pose communication problems that re- tives. Increased body size and the tran- quire new integrative solutions—includ- sition to a more diverse, higher quality Editors David McCurdy ing the kind of flexible associative diet probably does a lot to explain the Patricia C. Rice mechanisms commonly thought of as “in- rapid increase in hominid brain size seen Conrad Kottak telligent.” So perhaps we shouldn’t be over the past 2 million years. However, Column Editors too surprised that gorillas seem smarter humans have carried these trends to Constance P. deRoche than capuchin monkeys despite having extremes well beyond allometric expec- Lede Pedersen lower EQs. Within primates at least, tations, and also display some very in- General Anthropology ISSN 1537-1727 is pub- there is growing evidence that absolute teresting “mosaic” types of adaptations lished semiannually by the Gerneral Anthropol- brain size is a better predictor of cogni- (Rilling 2006, Sherwood, Subiaul, and ogy Division of the American Anthropological Association. © 2008 by the American Anthro- tive ability than EQ or Neocortex Ratio Zawidzki 2008). Of particular note are: pological Association. All Rights Reserved.The (Deaner et al. 2007). 1) disproportionate expansion of higher- goal of General Anthropology is to provide use- ful, timely, and readable information and ideas order parietal, temporal, and prefrontal from the four fields of anthropology and ap- But this still leaves us wondering why association cortices, 2) increased asym- plied anthropology. All requests for reprints and whales and elephants aren’t more intel- metry between left and right hemi- copyright permission should be sent to journalsrights@oxon. blackwellpublishing. com ligent than humans (at least according spheres, 3) increased connectivity of or by mail: Wiley-Blackwell Permissions Con- to our standards). Obviously size isn’t temporal and frontal lobes, and 4) troller, Blackwell Publishing Ltd., PO Box 805 everything, and the answer may have changes in the histology of occipital vi- 9600 Garsington Road, Oxford OX4 2ZG, United Kingdom something to do the greater density of sual cortex and medial prefrontal cor- cortical neurons in humans and the rela- tex. In a development that would sur- Correspondence should be sent to David tively high conduction velocity of primate prise Darwin and Engels not at all, these McCurdy, 1731 Princeton Avenue, St. Paul, MN, 55105, (651) 698-8492, Fax (651) 696-6324, cortical fibers (Roth and Dicke 2005). human neural specializations correspond e-mail [email protected]; or Patricia Brain size alone may be useful as a rough pretty closely to distinctive human tech- Rice, Dep Soc & Anth, West Virginia U, index of cognitive ability, but it is also nological, linguistic, and cultural capaci- Morgantown, WV 26506, (304) 293-5801, Fax (304) 293-5994, e-mail [email protected]. important to consider how and why par- ties. Conrad Kottak, 3742 Johns island, SC 29455, ticular brains got big. In many cases brain [email protected] size increases might be a product of se- Technology, language and culture Publications Board lection on body size, life history variables, Eric Lassiter [email protected] or perhaps a generalized “information y 2.6 million years ago, hominids had Celeste Ray [email protected] processing capacity.” From this one Bbegun to make simple stone cutting Emily Schultz [email protected] tools that were most likely used to process Tad Schurr [email protected] would expect a predictable pattern of Susan Sutton [email protected] allometric increase throughout the whole animal carcasses and access meat. brain, most likely produced by simple Although these tools were simple, they Page 2 General Anthropology were skillfully made. Experiments have visual field and the perception of the Linguistic communication is itself is shown that modern apes (bonobos) can three-dimensional form from relative a very complex activity that involves indeed fracture stone to make sharp cut- motion cues, and may be newly evolved many different parts of the brain, but ting edges, but that ten years of practice in humans. some of the core structures include in a supportive social context are still not Wernicke’s area of the left superior tem- sufficient to replicate the well-controlled Although it may not have taken ten poral lobe, Broca’s area of the left infe- flaking of the earliest hominid toolmak- years, early toolmakers clearly would rior frontal lobe, and the fiber bundle ers (Toth, Schick, and Semaw 2006). have required time, practice, and social known as the arcuate fasciculus that Two critical hominid pre-adaptations opportunities to acquire toolmaking skills. connects them. Thus it should probably probably helped pave the way for this This is especially true with respect to the come as no surprise that the temporal uniquely human skill: bipedalism and an increasingly refined bifacial tools that be- lobe has become both larger and better expansion of posterior parietal cortex. gan to appear after about 1.7 million connected to the frontal lobe in humans. Critical hominid pre-adaptations probably years ago. Increased social tolerance, helped pave the way for this uniquely without the distracting emotional arousal Language and toolmaking are clearly human skill: bipedalism and an expan- of dominance interactions, may have related to each other through the me- sion of posterior parietal cortex. been critical for such learning in much dium of social learning, but there is also the same way that docility seems to fa- increasing evidence of a more direct Efficient stone toolmaking requires vor the development of complex social neuro-evolutionary link. The hand and forceful precision grips that are not pos- cognition in domesticated dogs and foxes mouth are the two most complex and sible for chimpanzees, whose fingers (Hare and Tomasello 2005). Portions of flexible effectors of the human body (it must be stabilized for knuckle-walking. prefrontal cortex are known to play an is no coincidence that sign languages are As Darwin argued, bipedalism may have important role in emotional regulation and manual), and are represented in neigh- “freed” the hand to adapt for manipula- social cognition, and the more general boring sections of sensory and motor tive purposes. Adaptations of the hand expansion of this region in humans may cortex that only become fully distinct were also linked to changes in the ner- have some relation to the demands of during postnatal development. Adult net- vous system that enhanced hand-eye co- living and learning in close-knit groups. works for speech and object manipula- ordination. Such human specializations At the cellular level, it has also been sug- tion actually do overlap in Broca’s area include an increased number of direct gested that changes in the frequency and of the left inferior prefrontal cortex, connections between the hand and the spacing of distinctive “von Economo which is no longer seen as a dedicated cerebral cortex, changes in the cellular neurons” in human medial prefrontal “language center” but rather as a more organization of the motion processing cortex may support enhanced capacities generalized contributor to the under- system in occipital visual cortex, and an for the fast, intuitive assessment of so- standing and execution of hierarchically expansion of posterior parietal areas in- cial situations. structured action sequences. Thus it is volved in higher-order aspects of visual quite plausible that selection acting on perception. Social cohesion is also promoted by either toolmaking or language would talking, and human language may be a have promoted neural adaptations favor- Fossil evidence from the interior sur- kind of “social glue” that plays a similar able to both. Evidence from functional face of hominid skulls shows that pari- role to grooming in other primates or brain imaging strongly supports this link, etal expansion had already begun in aus- scent marking in pigs. But language is and a recent study has directly shown tralopithecines some time between 4 and more than just verbal grooming, and plays that Acheulean handaxe making acti- 2.5 million years ago (Holloway, a fundamental role in negotiating the so- vates Broca’s area in modern humans Broadfield, and Yuan 2004), possibly re- cial relationships, joint action, and shared (Stout et al. 2008). Well, almost —in a flecting adaptation to an increasingly realities that form the basis of distinc- fascinating twist, it is actually the right manipulative lifestyle and paving the way tively human culture. Studies of modern hemisphere equivalent of Broca’s area for the subsequent development of humans show just how important this that is activated.The left hemisphere is Oldowan stone technology. In fact, func- supportive cultural context has become classically considered the “language tional brain imaging studies of Oldowan- to the transmission of complex techno- hemisphere,” but as usual the truth is style toolmaking by modern humans logical skills as, for example, in learning turning out to be more complicated. (Stout and Chaminade 2007) have pin- to navigate on a U.S. Navy vessel While the left hemisphere is indeed domi- pointed a region of posterior parietal cor- (Hutchins 1995) or to produce a stone nant for phonology and syntax, the right tex that is particularly important to this adze in highland New Guinea (Stout hemisphere makes critical contributions skill. The particular region identified is 2002). to larger scale language elements like involved in representation of the central Fall 2008 Page 3 metaphor, figurative language, prosody, guistic, and cultural capacities played cognitive ability across non-human and discourse comprehension. Not so co- different roles at different times. It may primates.” Brain, Behavior and incidentally, a very similar division of la- not be possible, or even theoretically vi- Evolution 70:115-124. bor is evident in coordinated bimanual able, to identify a discrete “initial kick” tasks in which the right hemisphere-left or single “prime mover” in human brain Dunbar, R. I. M. hand system typically provides a stable evolution. 1998. “The social brain hypothesis.” postural frame for the rapid and precise Evolutionary Anthropology: Issues, action of the left hemisphere-right hand Paleolithic archaeology, hominid pa- News, and Reviews 6:178-190. system (at least in right handed people). leontology, and perhaps genetics as well This division is evident in everyday tasks can provide evidence of relative timing, Engels, F. like sweeping, threading a needle or cut- and it is certainly suggestive that stone 1954 (1883). “The part played by ting paper with scissors, and it turns out tools predate conventional indicators of labour in the transition from ape to man,” that the role of the left “support” hand is symbolic behavior (e.g. ornaments, art) in Dialectics of Nature, 2nd edition, particularly critical in stone toolmaking. by a wide margin. However, it is impor- 170-183. Moscow: Progress Publishers. tant to remember the real difficulty in The hemispheric segregation of fast finding direct archaeological indicators Hare, B., and M. Tomasello. and precise processing from more holis- of such complex and intangible phenom- 2005. “Human-like social skills in tic and stable processing seems to be a ena as “symbolism” or “culture.” Ar- dogs?” Trends in Cognitive Science general principle of the human brain, and chaeologists and biological anthropolo- 9:439-444. likely represents a response to the con- gists would be well advised to pay at- flicting requirements of the two modes. tention to insights from cultural anthro- Holloway, R. The increasing importance of this seg- pology, linguistics, psychology, ethology 1969. “Culture: a human domain.” regation in human evolution has pro- and related disciplines in order to avoid Current Anthropology 10:395-412. duced numerous cerebral asymmetries, an overly simplistic approach. New re- ranging from a macroscopic “twisting” search methods like brain imaging will Holloway, R., D. Broadfield, and M. (petalia) of the two hemispheres to mi- certainly have a contribution to make, but Yuan. croscopic differences in the spacing of real progress will come from the inte- 2004. The human fossil record, neurons in Broca’s area, as well as the gration of ideas and approaches in a truly volume 3, brain endocasts–the 90% prevalence of right-handedness in interdisciplinary fashion, across the four paleoneurological evidence. Hoboken, Homo sapiens (compared to 67% in fields of anthropology and beyond. NJ: Wiley-Liss. chimpanzees). Once again toolmaking and language stand out as likely contribu- References Hutchins, E. tors to these specializations of the hu- 1995. Cognition in the Wild. Cam- man brain. Byrne, R., and A. Whiten. Editors. bridge MA: MIT Press. 1988. Machiavellian intelligence: Chicken or Egg? social expertise and the evolution of Rilling, J. K. intellect in monkeys, apes and hu- 2006. “Human and nonhuman primate Ongoing research continues to sup- mans. Oxford: Clarendon Press. brains: are they allometrically scaled ver- port long-held intuitions regarding the sions of the same design?” Evolutionary tight links between technology, language, Darwin, C. Anthropology 15:65-77. and culture in human brain evolution, 1871. The Descent of Man and Se- while adding a great deal to our under- lection in Relation to Sex. Vol. 1. Lon- Roth, G., and U. Dicke. 2005. “Evolution of the brain and in- standing of context, timing, and mecha- don: John Murray. telligence.” Trends in Cognitive Sciences nism. However, the very tightness of 9:250-257. these evolutionary relationships makes Deacon, T. W. it difficult to distinguish cause from con- 1997. The symbolic species: The Sherwood, C. C., F. Subiaul, and T. W. sequence. Fossil evidence has pretty co-evolution of language and the Zawidzki. decisively supported Engels’ supposition brain. New York: W.W. Norton. 2008. “A natural history of the hu- that bipedalism and the hand came first, man mind: tracing evolutionary changes but did toolmaking lead to language or Deaner, R. O., K. Isler, J. Burkart, and in brain and cognition.” Journal of vice versa? Actually this sounds a lot like C. van Schaik. Anatomy 212:426-454. a chicken or the egg type question, and 2007. “Overall brain size, not it is likely that evolving technological, lin- encephalization quotient, best predicts Page 4 General Anthropology Stout, D. Teaching continued from page 1 steps, and short. At the opposite end of 2002. “Skill and cognition in stone tool this spectrum with experienced students, production: An ethnographic case study critical and analytical skills to any situa- the course may be entirely student-run, from Irian Jaya.” Current Anthropol- tion they might encounter. Developing with students facilitating all class ses- ogy 45:693-722. translatability that is deeply connected sions, creating the syllabus, assignments, to real-world skills makes it important and expectations. Stout, D., and T. Chaminade. to create opportunities for students to 2007. “The evolutionary neuro- apply knowledge outside classroom. The introductory course science of tool making.” Neuropsychologia 45:1091-1100. Another element that I view as cru- typical introductory course assign- cial is challenging students to get out of Ament involves a small group of stu- Stout, D., N. Toth, K. D. Schick, and their ‘comfort zone,’ especially since so dents—no more than four—facilitating T. Chaminade. many of them have lived their lives an entire class meeting. I frame this as 2008. “Neural correlates of Early within pretty definite geographic, ideo- teaching rather than presentation, a dis- Stone Age tool-making: technology, lan- logical, and/or social borders. The idea, tinction I feel is especially important. guage and cognition in human evolution.” in short, is to explode the implications of Teaching establishes collaborative learn- Philosophical Transactions of the their learning outward into their lives. ing/teaching as a mode of engagement Royal Society of London B doi:10.1098/ and also moves students toward shap- rstb.2008.0001:1939-1949. Attending to this variety of experi- ing the class session in ways they don’t ences and modes of engagement can be usually think of when doing a presenta- Toth, N., K. D. Schick, and S. Semaw. a tricky task, and I have lots of ways to tion. 2006. “A comparative study of the try to get at them. My approaches range stone tool-making skills of Pan, from highly structured introductory For the introductory course, students Australopithecus, and Homo sapiens,” classes that require students to complete are evaluated on the sophistication of con- in The Oldowan: case studies into the a few guided assignments to upper divi- cepts presented, clarity of communica- earliest stone age. Edited by N. Toth sion courses run entirely by students. tion, connections to class issues and con- and K. D. Schick, 155-222. Gosport, IN: Enlisting student support and participa- cepts, and evidence of collaboration in Stone Age Institute Press. tion is key, both for getting them to ‘buy the presenting group. Guidelines also in- into’ sometimes unfamiliar approaches clude a requirement for them to include Washburn, S. L. to learning, and to develop a cohesive an active or experiential learning exer- 1960. “Tools and Human Evolution.” and productive classroom vibe. cise as a way to ensure that the class Scientific American 203:3-15. session moves well beyond a standard I take a purposefully developmental lecture. To make sure they prepare Claire Smith, GAD Dis- approach in cultivating students as co- ahead, students must submit to me a tinguished Lecturer at learners and independent thinkers. Ba- detailed lesson plan beforehand. I also sically what this means (and it’s not ask them to think especially about ad- AAA San Francisco rocket science) is that assignments, tasks, dressing issues or questions that may not Meetings and President activities and expectations are calibrated yet have been covered by me in the pre- of the World Archaeo- to the level of the course and, often, to ceding few days, and I urge them to logical Congress Will the makeup of the group of students in meet with me as they plan their work. any given class. Furthermore, I look for While students do not always or even Speak on: strategies that are designed to incremen- often feel completely comfortable with tally build skills for students so that as my assurances that we really are a team, Archaeologists in Action: they take multiple classes with me, their I find that this approach begins the work Collaboration, Inclusion, capacities are stretched and enhanced. of creating the learning process as a This enables them to enculturate less ex- group effort and generally raises the level and Engagement. perienced students to my classroom en- of classroom engagement across the vironment and practices. In lower level board. Because even the largest classes Friday, November 21, 6 p.m. classes, or classes in which I find my- at Occidental College contain only about in Continental Parlor 2. self with few students experienced in this 35 students, this is a workable format, Reception with cash bar to sort of independent exploration, I try to but I think it could be adjusted to work provide assignments that are designed with somewhat larger groups. follow by me, clear-cut, designed as a series of Fall 2008 Page 5