stone age institute publication series Series Editors Kathy Schick and Nicholas Toth Stone Age Institute Gosport, Indiana and Indiana University, Bloomington, Indiana Number 1. THE OLDOWAN: Case Studies into the Earliest Stone Age Nicholas Toth and Kathy Schick, editors Number 2. BREATHING LIFE INTO FOSSILS: Taphonomic Studies in Honor of C.K. (Bob) Brain Travis Rayne Pickering, Kathy Schick, and Nicholas Toth, editors Number 3. THE CUTTING EDGE: New Approaches to the Archaeology of Human Origins Kathy Schick, and Nicholas Toth, editors Number 4. THE HUMAN BRAIN EVOLVING: Paleoneurological Studies in Honor of Ralph L. Holloway Douglas Broadfield, Michael Yuan, Kathy Schick and Nicholas Toth, editors STONE AGE INSTITUTE PUBLICATION SERIES NUMBER 4 Series Editors Kathy Schick and Nicholas Toth THE HUMAN BRAIN EVOLVING: Paleoneurological Studies in Honor of Ralph L. Holloway Editors Douglas Broadfield Florida Atlantic University Michael Yuan Columbia University Kathy Schick Stone Age Institute & Indiana University Nicholas Toth Stone Age Institute & Indiana University Stone Age Institute Press · www.stoneageinstitute.org 1392 W. Dittemore Road · Gosport, IN 47433 FRONT COVER CAPTIONS Center: Portrait of Ralph L. Holloway. Upper left: A modern human brain. Upper right: Ralph measuring landmarks on an endocast ca. 1976. Lower right: Homo habilis cranium KNM-ER-1813 from Koobi Fora, Kenya (photo by Holloway). Lower left: Ralph with an endocast of the Flores “hobbit” cranium. Published by the Stone Age Institute. ISBN-10: 0-9792276-3-1 ISBN-13: 978-0-9792276-3-9 Copyright © 2010, Stone Age Institute Press. All right reserved under International and Pan-American Copyright Conventions. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, without permission in writing from the publisher. CHAPTER 19 HOMININ BRAIN REORGANIZATION, TECHNOLOGICAL CHANGE, AND COGNITIVE COMPLEXITY NICHOLAS TOTH AND KATHY SCHICK ABSTRACT long distances of stones used in making tools, de-fleshing carcasses, or even cannibalism. This chapter will discuss the relationships be- Holloway (1967, 1969, 1981) suggested that stone tween hominin brain evolution (encephalization, reor- tool making and language might have had similar ganization) and the prehistoric archaeological record, cognitive underpinnings, particularly if the stone most notably prehistoric technological material culture tools showed clear evidence of standardization of and behavioral patterns, to assess the cognitive capabili- form from elements (e.g. cobbles) that had very ties evident within different grades of hominins through different initial shapes.” time. Seven time intervals, spanning from 3.25 million years ago to the present, are sampled to examine major Ralph Holloway, Douglas Broadfield, and Michael changes in hominin evolution, technology, and behavior Yuan, 2004. The Human Fossil Record, Volume over that period of time. Holloway et al.’s (2004) pro- Three: Brain Endocasts - The Paleoneurological posed three major stages of hominin brain evolution will Evidence. Hoboken: John Wiley & Sons. Pp. 288- be discussed in this context. We will argue that each of 289. these three stages appear to be correlated with important “If brains were lard, Jethro couldn’t grease a changes in material culture and behavior as well. Hy- skillet.” potheses that attempt to explain the causes of hominin encephalization and brain reorganization are discussed. Jed Clampett discussing his hapless nephew in the 1960’s sitcom The Beverly Hillbillies. KEY WORDS The hominin fossil record, built up over the past 150 years, has shown us many of the major trends in human Brain evolution, evolution of human cognition, Pal- evolution pertaining to anatomy and functional morphol- aeolithic archaeology, stone tools ogy. Studies of extant non-mammalian and mammalian (of particular interest, primate) species have shown us INTRODUCTION relationships between brain anatomy and behavioral, perceptual, and problem-solving capabilities. Ralph Hol- “The earliest phases of hominid existence are loway has been at the forefront of human brain evolu- particularly open to speculative embroidery. But tion studies for over four decades. We have personally when all is said and done, it remains the stone known him for three of those decades, and have valued tool industries or traditions that can inform us most his scholarship, collegiality, and friendship. This chapter about hominid cognitive abilities. This does not is inspired by the corpus of work that Ralph and his col- mean that we disregard archaeological contexts leagues have done in paleoneurology, and the impact this such as the faunal remains, home bases, the work has had in human origins research. evidence (or lack of it) for fire, importation over The human palaeontological record and the prehis- 294 3 The Human Brain Evolving: Papers in Honor of Ralph L. Holloway Toth and Schick 4 295 toric archaeological record are the two major lines of for geological periods as opposed of the highly contro- evidence that shed light on the evolution of human cog- versial restructuring of the Plio-Pleistocene boundary: nitive abilities. Brain endocasts from fossil hominin cra- here we will show dates for the Pliocene (ca. 5.3 to 1.8 nia can yield important information regarding brain size, million years ago); Early Pleistocene (ca. 1.8 million to possible brain to body relationships, and brain structure 780,000 years ago); Middle Pleistocene (ca. 780,000- and organization. The archaeological record can yield 125,000 year ago); Late Pleistocene (ca. 125,000 years important information regarding technological patterns, ago to 11,000 years ago); Holocene (11,000 years ago foresight and planning, skill, cognitive capabilities, and to the present.) The dating of hominin fossils, notably dexterity. In this chapter we will review the human pal- those found on the surface in contexts without applicable aeontological and archaeological record, sampling time radiometric dating techniques, is sometimes ambiguous, intervals of 500,000 years to explore the relationships so we have been as cautious as possible in assigning between hominin brain reorganization, technological dates to these important fossils. The earliest dates for change, and cognitive complexity. We will examine the Homo erectus are somewhat controversial, but here we major stages of brain evolution forwarded by Holloway will use a date of approximately 1.75 million years. et al. (2004) and see whether these appear to be roughly There is much debate regarding the taxonomic status contemporaneous with behavioral punctuations in the of early hominin fossil as well as evolutionary ancestor- prehistoric archaeological record. descendant relationships between taxa. In this chapter As palaeoanthropologists and experimental archae- we will take a conservative position, for example some- ologists focusing on Palaeolithic archaeology, we each times grouping the taxa Homo rudolfensis and Homo have over 35 years of experience in stone-knapping and habilis into “early Homo.” We group the proposed taxa other forms of material culture over a wide range of hu- Homo ergaster, Homo georgicus, and Homo anteces- man technologies through time. This experience hope- sor into Homo erectus. We also group most non-erectus fully gives us enhanced insights into the level of skill and hominin fossils between 750,000 and 250,000 years ago planning that is required to produce a given artifact form into Homo heidelbergensis (what some researchers pre- or set of artifacts, as well as into what types of prehistoric fer to call “archaic Homo sapiens.” We will assign the artifacts may have been intentionally produced or simply Neandertals to their own taxon, Homo neandertalensis, represent by-products of manufacture or use. We also although some anthropologists would include them in have extensive experience in experimentally using stone our own species. We will also group most non-Nean- tools for a host of activities, including animal butchery dertal fossils of the last 250,000 years (excluding rel- for meat consumption, bone-breaking for marrow and ict Homo erectus fossils of East Asia and the enigmatic brain tissue processing, nut-cracking, wood-working, Flores fossils) into Homo sapiens (anatomically modern hide-scraping, etc. These experiments have provided us or near-modern humans). This includes all of the Afri- a wealth of experience to inform insights into the subtle can fossils from North Africa and Sub-Saharan Africa relationships between tool form and tool function. in this time period. In this chapter we will also use the In past publications we have discussed aspects of mean cranial capacities of hominin taxa and estimated the relationships between prehistoric material culture anthropocentric encephalization quotient or EQ (modern and hominin brain evolution and cognition, includ- human =1.00; modern chimpanzees = 0.34) reported by ing Schick and Toth, 1993, 2009; Toth, 1985a, 1985b, Holloway et al. (2004). 1990;Toth and Schick, 1993, 2006; Toth, Schick, and While it is appreciated that at any stage of human Semaw, 2006; Stout et al., 2000, 2006, 2009, 2010. evolution, we can only be sure we are seeing minimal, We refer the reader to a number of other publications but not necessarily maximal expressions of cognitive involving hominin brain evolution and the archaeologi- abilities in the form of the material culture and behav- cal record, for example Allman, 2000; Ambrose, 2001;