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Anthropology

<OpenstaxParagraph>
	The previous chapter introduced the australopithecines, who were diverse in their physical characteristics (gracile and robust), with large jaws and teeth and small brain size. A key characteristic shared by both the australopithecines and the genus <OpenstaxEm>Homo</OpenstaxEm> is bipedalism. The transition to bipedalism is linked with various anatomical changes, including longer legs, changes in spinal curvature, and the development of arches in the feet to conserve energy and increase balance when walking.
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	What criteria other than bipedalism might be used to classify a species under the genus <OpenstaxEm>Homo</OpenstaxEm>? Many anthropologists have attempted to establish specific criteria to use in determining a classification of <OpenstaxEm>Homo.</OpenstaxEm> Paleoanthropologists Mary <OpenstaxTerm>Leakey</OpenstaxTerm>, Louis <OpenstaxTerm>Leakey</OpenstaxTerm>, and John <OpenstaxTerm>Napier</OpenstaxTerm>, as well as primatologist Phillip <OpenstaxTerm>Tobias</OpenstaxTerm>, were among the first to extensively study the fossils of <OpenstaxTerm><OpenstaxEm>Homo habilis</OpenstaxEm></OpenstaxTerm>, considered to be one of the earliest species in the genus <OpenstaxEm>Homo</OpenstaxEm>. <OpenstaxTerm><OpenstaxEm>H. habilis</OpenstaxEm></OpenstaxTerm> had a brain size of around 661–700 cc, which was larger than the australopithecines’, with hands that were capable of the dexterity needed for making tools, due to bone structure changes and a repositioning of the thumb, which allowed for better grip.
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	The <OpenstaxTerm>type specimen</OpenstaxTerm> OH 7 of <OpenstaxEm>H. habilis</OpenstaxEm> dated between 2 and 1.7 MYA and was found in 1960 at <OpenstaxTerm>Olduvai Gorge</OpenstaxTerm> by Jonathan and Mary Leakey. It was described by Louis Leakey in 1964. Type specimen refers to a specimen that serves as the standard for the taxon or classification group for that species. OH 7 is the identification or accession number of this specific specimen and stands for “Olduvai Hominid #7.” The specimen consisted of a partial juvenile skull, hand, and foot bones. It possessed teeth that were much smaller than those of any australopithecine and was possibly in coexistence with the robust australopithecines (<OpenstaxEm>Paranthropus</OpenstaxEm>). Based on an <OpenstaxTerm>endocranial cast</OpenstaxTerm> (an imprint of the interior of the brain case), it was determined that <OpenstaxEm>H. habilis</OpenstaxEm> may have possessed what is called a Broca’s area in the brain. <OpenstaxTerm>Broca’s area</OpenstaxTerm>, which includes two <OpenstaxTerm>Brodmann areas</OpenstaxTerm> (referred to as 44 and 45), is located in the middle of the left cerebral cortex of the brain and is especially important for speech development (<a href="#fig-00001">Figure 5.2</a>). Some scientists have suggested that <OpenstaxEm>H. habilis</OpenstaxEm> started to develop the neural networks necessary for human speech, while others argue that <OpenstaxEm>H. habilis</OpenstaxEm> probably already had speech.
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<OpenstaxFigure id="fig-00001" src="https://openstax.org/apps/archive/20240226.174525/resources/24bfa5831e2408df20d4917ff6b2d129b7ee825e" alt="A diagram of the brain with two areas circled in the forebrain, one labelled 44 and the other labelled 45. Areas 44 and 45 are directly next to each other." mediaType="image/jpeg" width="800" height="620" />
<OpenstaxFigureText width="800">
	Figure 5.2 Position of the Broca’s area in the brain, consisting of Brodmann areas 44 (yellow) and 45 (blue). Broca’s area is associated with speech development and may have been present in the brain of H. habilis. (credit: Fatemeh Geranmayeh, Sonia L. E. Brownsett, Richard J. S. Wise/Wikimedia Commons, CC BY 3.0)
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	The <OpenstaxTerm>postcranial features</OpenstaxTerm> (skeletal structures in the body other than the skull) of <OpenstaxEm>Homo habilis</OpenstaxEm> are not as well established, as is the case for many other early hominin fossils. This can be problematic, as many hominin species coexisted with overlapping traits. Likewise, it can be problematic to have postcranial material and not the cranium or skull. The skull often serves as a diagnostic tool when postcranial materials do not provide enough evidence or provide confusing evidence.
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	Based on their research on <OpenstaxEm>H. habilis</OpenstaxEm>, Mary Leakey, Louis Leakey, and John Napier proposed the following criteria for classifying <OpenstaxEm>Homo</OpenstaxEm>: a brain size over 600 cc; a round, globular skull; tool use; reduced prognathism (protrusion of the jaw) and smaller jaws and mandibles; humanlike postcranial features; and feet that are fully adapted for walking (Leakey, Tobias, and Napier 1964). While this list established specific and fairly comprehensive guidance, the diversity of traits and the ways in which they overlapped didn’t always line up with the criteria.
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	<OpenstaxEm>H. habilis</OpenstaxEm> has been at the center of several debates regarding their taxonomic position and relationship with other early archaic <OpenstaxEm>Homo</OpenstaxEm> species. For example, <OpenstaxEm>H. habilis</OpenstaxEm> was initially believed to have been a direct human ancestor through the lineage of <OpenstaxTerm><OpenstaxEm>Homo erectus</OpenstaxEm></OpenstaxTerm> and then <OpenstaxTerm>modern humans</OpenstaxTerm>. This viewpoint is now debated and has resulted in a scientific divide between those supporting <OpenstaxEm>H. habilis</OpenstaxEm> and those suggesting another <OpenstaxEm>Homo</OpenstaxEm> species, <OpenstaxTerm><OpenstaxEm>H. rudolfensis</OpenstaxEm></OpenstaxTerm>, as being the ancestor of <OpenstaxEm>H. erectus. H. rudolfensis</OpenstaxEm> is an archaic <OpenstaxEm>Homo</OpenstaxEm> dated to about 2 MYA, which coexisted with other <OpenstaxEm>Homo</OpenstaxEm> species during that time period. A cranium was discovered in 1972 along <OpenstaxTerm>Lake Turkana</OpenstaxTerm> in Kenya by Bernard Ngeneo, a local Kenyan. The specimen was later described by paleoanthropologist Richard Leakey. There is a lot that is not known about this species; scientists are missing postcranial materials, and as of yet no tools have been found. There are hypotheses that propose that <OpenstaxEm>H. rudolfensis</OpenstaxEm> might be a <OpenstaxEm>H. habilis</OpenstaxEm> male, exhibiting a larger cranium than that seen in a female <OpenstaxEm>H. habilis</OpenstaxEm>. Others suggest it is a completely different species. Another controversy centers on tool use. While <OpenstaxEm>Homo habilis</OpenstaxEm> was long regarded as the earliest hominin to use stone tools, it has been determined, based on evidence of cutmarks, that at least one australopithecine (<OpenstaxEm>A. garhi</OpenstaxEm>) used stone tools before <OpenstaxEm>H. habilis</OpenstaxEm>, at around 2.6 MYA (Semaw et al. 1997).
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<OpenstaxFigure id="fig-00002" src="https://openstax.org/apps/archive/20240226.174525/resources/7cc4ae4f17f3221a0233482bfa3a00f08572f9d1" alt="The H. rudolfensis skull is larger and more elongated, with a longer area beneath the eyes, while the H. habilis skull is wider and rounder." mediaType="image/jpeg" width="800" height="657" />
<OpenstaxFigureText width="800">
	Figure 5.3 The specimen of H. rudolfensis on the left is noticeably different from that of H. habilis on the right. (credit: Conty/Wikimedia Commons, CC BY 3.0)
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	While there are still questions as to the phylogenetic relationship of <OpenstaxEm>H. habilis</OpenstaxEm> and <OpenstaxEm>H. rudolfensis</OpenstaxEm>, there is general agreement that <OpenstaxEm>Homo</OpenstaxEm> did evolve from <OpenstaxEm>Australopithecus</OpenstaxEm>. The timing and placement of the split between <OpenstaxEm>Australopithecus</OpenstaxEm> and <OpenstaxEm>Homo</OpenstaxEm>, however, is still debated. <OpenstaxEm>H. habilis</OpenstaxEm> was determined to not be an <OpenstaxEm>Australopithecus</OpenstaxEm> due to its smaller teeth, a humanlike foot, and hand bones that suggested an ability to manipulate objects with precision.
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	One of the main considerations in classifying <OpenstaxEm>H. habilis</OpenstaxEm> as a <OpenstaxEm>Homo</OpenstaxEm> and not an <OpenstaxEm>Australopithecus</OpenstaxEm> was its <OpenstaxTerm>cranial capacity</OpenstaxTerm>, which is a measurement that indicates brain size. With some exceptions, cranial capacity can serve as an indicator of where a hominin fossil might belong in the hominin phylogenetic tree. <OpenstaxTerm>Encephalization</OpenstaxTerm> refers to a progressive increase in brain size over time. In human evolution, we can observe encephalization beginning with <OpenstaxEm>Homo habilis</OpenstaxEm> and progressing more rapidly through <OpenstaxEm>H. erectus</OpenstaxEm>. Encephalization correlates with an increase in behavioral, cognitive, and cultural complexity. Cognitive developments correspond with our ability to construct and form ideas, including the ability think in and communicate via symbolic and abstract language, such as that used in storytelling, ritual, and art. There are always exceptions, however, such as the island-dwelling, small-brained <OpenstaxEm>H. floresiensis</OpenstaxEm>, who will be introduced later in this chapter. In spite of having a very small brain, <OpenstaxEm>H. floresiensis</OpenstaxEm> made and used tools and built fires. This discovery has challenged what we thought we knew about the correlation of brain size and cognitive development in human evolution.
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	The <OpenstaxTerm>encephalization quotient (EQ)</OpenstaxTerm> can serve as a good indicator (with some exceptions) of classification within the genus <OpenstaxEm>Homo</OpenstaxEm>. The encephalization quotient is a calculation arrived at by comparing the ratio between actual brain size (determined with either a mass or volume calculation) and expected brain size. Body size is a factor in these measurements as expected brain size reflects the relationship between brain and body size for a given taxonomic group (Jerison 1973). The larger the brain weight relative to the overall body weight, the more likely that the brain was used for more complex cognitive tasks. Harry J. Jerison (1973) was the first to develop EQ measurements. The formula he used for <OpenstaxTerm>calculating EQ</OpenstaxTerm> in birds and mammals is brain mass/0.12 × (body mass)0.66. Other formulas have also been proposed, such as EQ = brain mass (11.22 × body mass 0.76) (Martin 1981). While EQ is a strong tool for studying brain size in early hominins, there are always potential margins of error when dealing with fragmentary fossils, and increasingly alternative forms of measurements are being proposed. One study proposes that EQ should no longer be used as a tool in calculating brain size in primates and other vertebrate species, based on the premise that cognitive performance does not depend on body size and so body size should not be included in the formula (Schaik et al. 2021). Other theories consider the number of cortical neurons and neural connections as most important when considering cognitive ability (Roth and Dicke 2012). According to this approach, the density of the cortex is more associated with intelligence than is brain size. These alternate approaches would perhaps better explain those exceptions in the fossil records, such as <OpenstaxEm>H. floresiensis</OpenstaxEm>. Other interesting research is looking at potential levels of cognition and memory as it relates to levels of tool complexity (Read and van der Leeuw 2008).
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	In spite of these criticisms, many see EQ measurements as providing fairly consistent results. Modern humans (<OpenstaxEm>Homo sapiens</OpenstaxEm>) have an EQ of roughly 6.0–7.0 (meaning that their brain mass is six to seven times greater than what one would expect to find in a comparable mammal of the same body size). <OpenstaxEm>H. erectus</OpenstaxEm> has an EQ of 4.0, while for an australopithecine EQ is around 2.5 to 3.0 (Fuente 2012, 227). <a href="#fig-00003">Figure 5.4</a> shows increases in average brain sizes for various species over time.
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<OpenstaxFigure id="fig-00003" src="https://openstax.org/apps/archive/20240226.174525/resources/95258a82fcf35cb2a55a18b79d4feeb19816a310" alt="A graph with “Time ” on the x-axis and “Volume ” on the y-axis. Seven labelled schematics of brains appear within the graph, with specimens growing noticeably larger in the period between 2.0 mya and the present." mediaType="image/jpeg" width="1000" height="536" />
<OpenstaxFigureText width="1000">
	Figure 5.4 After remaining steady for millennia, average brain size increases noticeably in the last two million years. (Xiujie, Wu, and Norton 2007). (credit: Gisselle Garcia, artist (brain images), CC BY 4.0)
</OpenstaxFigureText>

5.1.2 The Challenge of Defining the Genus Homo

1 What Is Anthropology?

1.1 The Study of Humanity, or "Anthropology Is Vast"

1.1.1 The Heart of Anthropology: Central Narrative and Commitments

1.1.2 Central Commitment #1: Exploring Sociocultural Diversity

1.1.3 Central Commitment #2: Understanding How Societies Hold Together

1.1.4 Central Commitment #3: Examining the Interdependence of Humans and Nature

1.2 The Four-Field Approach: Four Approaches within the Guiding Narrative

1.2.1 Biological Anthropology

1.2.2 Archaeology

1.2.3 Cultural Anthropology

1.2.4 Linguistic Anthropology

1.2.5 How the Four Fields Work Together: The Example of Race

1.3 Overcoming Ethnocentrism

1.3.1 Enculturation and Ethnocentrism

1.3.2 Primitivism and Orientalism

1.4 Western Bias in Our Assumptions about Humanity

1.4.1 Primitivism and Orientalism in Popular Culture

1.4.2 The Bias of Backwardness

1.5 Holism, Anthropology’s Distinctive Approach

1.5.1 Society as an Integrated Whole

1.5.2 Sources of Contradiction, Conflict, and Change

1.6 Cross-Cultural Comparison and Cultural Relativism

1.6.1 Relativism Is Not “Anything Goes”

1.6.2 Morality, Activism, and Cultural Relativism

1.7 Reaching for an Insider’s Point of View

1.7.1 The Challenge of Representing Others

1.7.2 Collaborative Methods of Representation

1.7.3 Working across Cultures toward Common Goals

1.7.4 Suggested Readings

2 Methods: Cultural and Archaeological

2.1 Archaeological Research Methods

2.1.1 Archaeological Techniques

2.1.2 Archaeological Dating Methods

2.2 Conservation and Naturalism

2.2.1 Early Efforts

2.2.2 Salvage Anthropology

2.2.3 Museum Collections

2.2.4 Interpretation and Voice

2.3 Ethnography and Ethnology

2.3.1 The Development of Ethnography and Ethnology

2.3.2 Perspective and Interpretation in Ethnography

2.4 Participant Observation and Interviewing

2.4.1 Participant Observation

2.4.2 Interviewing Informants

2.4.3 Ethical Considerations

2.5 Quantitative and Qualitative Analysis

2.5.1 Differences between Quantitative and Qualitative Information

2.5.2 Modeling

2.5.3 The Science of Anthropology

2.6 Collections

2.6.1 Archives

2.6.2 Three-Dimensional Collections

2.6.3 Ownership

2.6.4 Suggested Readings

3 Culture Concept Theory: Theories of Cultural Change

3.1 The Homeyness of Culture

3.2 The Winkiness of Culture

3.3 The Elements of Culture

3.3.1 Culture Is What We Make

3.3.2 Culture Is What We Do

3.3.3 Culture Is What We Think

3.4 The Aggregates of Culture

3.4.1 Symbols

3.4.2 Ritual

3.4.3 Social Structure

3.5 Modes of Cultural Analysis

3.5.1 Evolution, Adaptation, and Historical Particularism

3.5.2 Functionalism

3.5.3 Structuralism

3.5.4 Ontology

3.6 The Paradoxes of Culture

3.6.1 Paradox 1: Culture Is Continuous, but It Changes

3.6.2 Paradox 2: Culture Is Bounded but Mobile

3.6.3 Paradox 3: Culture Is Consensual but Contested

3.6.4 Paradox 4: Culture Is Shared, but It Varies

3.6.5 Suggested Readings

4 Biological Evolution and Early Human Evidence

4.1 What Is Biological Anthropology?

4.1.1 Looking to the Deep Past

4.1.2 Exploring What It Means to Be Human

4.2 What’s in a Name? The Science of Taxonomy

4.2.1 Defining the Science of Taxonomy

4.2.2 Defining a Species

4.3 It’s All in the Genes! The Foundation of Evolution

4.3.1 The Units of Life

4.3.2 Gregor Mendel and the Laws of Heredity

4.3.3 Mendelian Inheritance in Humans

4.4 Evolution in Action: Past and Present

4.4.1 Early Evolutionists and the Fixity of Species

4.4.2 Charles Darwin’s Role in Changing Views of the Natural World

4.4.3 Understanding Darwin’s Theory of Natural Selection

4.5 What Is a Primate?

4.5.1 What Is a Primate?

4.5.2 Primate Behavioral Variation

4.5.3 Explaining Primate Success

4.5.4 Primate Classification and Taxonomy

4.6 Origin of and Classification of Primates

4.6.1 Understanding Concepts of Time

4.6.2 Fossils and Dating Methods

Question	Answer
a region in the frontal lobe of the brain (which includes two Brodmann areas) first found in H. habilis and connected with the production of speech.	Broca’s area
the volume of the interior of the cranium or skull, providing an approximate size of the brain.	cranial capacity
increased brain size over time.	encephalization
an impression taken from the inside of the cranium (braincase), frequently used by paleoanthropologists to determine the shape and approximate size of the brain in hominids and other primates.	endocranial cast
skeletal material found in the body that is not related to the skull (cranial bones).	postcranial features