The biting performance of Homo sapiens and Homo heidelbergensis

Ricardo Miguel Godinho, Laura C. Fitton, Viviana Toro-Ibacache, Chris B. Stringer, Rodrigo Lacruz, Timothy Bromage, Paul O'Higgins

Research output: Contribution to journalArticle

Abstract

Modern humans have smaller faces relative to Middle and Late Pleistocene members of the genus Homo. While facial reduction and differences in shape have been shown to increase biting efficiency in Homo sapiens relative to these hominins, facial size reduction has also been said to decrease our ability to resist masticatory loads. This study compares crania of Homo heidelbergensis and H. sapiens with respect to mechanical advantages of masticatory muscles, force production efficiency, strains experienced by the cranium and modes of deformation during simulated biting. Analyses utilize X-ray computed tomography (CT) scan-based 3D models of a recent modern human and two H. heidelbergensis. While having muscles of similar cross-sectional area to H. heidelbergensis, our results confirm that the modern human masticatory system is more efficient at converting muscle forces into bite forces. Thus, it can produce higher bite forces than Broken Hill for equal muscle input forces. This difference is the result of alterations in relative in and out-lever arm lengths associated with well-known differences in midfacial prognathism. Apparently at odds with this increased efficiency is the finding that the modern human cranium deforms more, resulting in greater strain magnitudes than Broken Hill when biting at the equivalent tooth. Hence, the facial reduction that characterizes modern humans may not have evolved as a result of selection for force production efficiency. These findings provide further evidence for a degree of uncoupling between form and function in the masticatory system of modern humans. This may reflect the impact of food preparation technologies. These data also support previous suggestions that differences in bite force production efficiency can be considered a spandrel, primarily driven by the midfacial reduction in H. sapiens that occurred for other reasons. Midfacial reduction plausibly resulted in a number of other significant changes in morphology, such as the development of a chin, which has itself been the subject of debate as to whether or not it represents a mechanical adaptation or a spandrel.

Original languageEnglish (US)
Pages (from-to)56-71
Number of pages16
JournalJournal of Human Evolution
Volume118
DOIs
StatePublished - May 1 2018

Fingerprint

Homo
cranium
muscle
efficiency
performance
muscles
increased efficiency
tomography
tooth
food
food preparation
Homo sapiens
computed tomography
Pleistocene
ability
teeth
X-radiation
evidence

Keywords

  • Finite element analysis
  • Homo heidelbergensis
  • Homo sapiens
  • Paleoanthropology
  • Virtual anthropology

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Anthropology

Cite this

Godinho, R. M., Fitton, L. C., Toro-Ibacache, V., Stringer, C. B., Lacruz, R., Bromage, T., & O'Higgins, P. (2018). The biting performance of Homo sapiens and Homo heidelbergensis. Journal of Human Evolution, 118, 56-71. https://doi.org/10.1016/j.jhevol.2018.02.010

The biting performance of Homo sapiens and Homo heidelbergensis. / Godinho, Ricardo Miguel; Fitton, Laura C.; Toro-Ibacache, Viviana; Stringer, Chris B.; Lacruz, Rodrigo; Bromage, Timothy; O'Higgins, Paul.

In: Journal of Human Evolution, Vol. 118, 01.05.2018, p. 56-71.

Research output: Contribution to journalArticle

Godinho, RM, Fitton, LC, Toro-Ibacache, V, Stringer, CB, Lacruz, R, Bromage, T & O'Higgins, P 2018, 'The biting performance of Homo sapiens and Homo heidelbergensis', Journal of Human Evolution, vol. 118, pp. 56-71. https://doi.org/10.1016/j.jhevol.2018.02.010
Godinho, Ricardo Miguel ; Fitton, Laura C. ; Toro-Ibacache, Viviana ; Stringer, Chris B. ; Lacruz, Rodrigo ; Bromage, Timothy ; O'Higgins, Paul. / The biting performance of Homo sapiens and Homo heidelbergensis. In: Journal of Human Evolution. 2018 ; Vol. 118. pp. 56-71.
@article{82a37f9420ec4a65a37fc22c5747e5b9,
title = "The biting performance of Homo sapiens and Homo heidelbergensis",
abstract = "Modern humans have smaller faces relative to Middle and Late Pleistocene members of the genus Homo. While facial reduction and differences in shape have been shown to increase biting efficiency in Homo sapiens relative to these hominins, facial size reduction has also been said to decrease our ability to resist masticatory loads. This study compares crania of Homo heidelbergensis and H. sapiens with respect to mechanical advantages of masticatory muscles, force production efficiency, strains experienced by the cranium and modes of deformation during simulated biting. Analyses utilize X-ray computed tomography (CT) scan-based 3D models of a recent modern human and two H. heidelbergensis. While having muscles of similar cross-sectional area to H. heidelbergensis, our results confirm that the modern human masticatory system is more efficient at converting muscle forces into bite forces. Thus, it can produce higher bite forces than Broken Hill for equal muscle input forces. This difference is the result of alterations in relative in and out-lever arm lengths associated with well-known differences in midfacial prognathism. Apparently at odds with this increased efficiency is the finding that the modern human cranium deforms more, resulting in greater strain magnitudes than Broken Hill when biting at the equivalent tooth. Hence, the facial reduction that characterizes modern humans may not have evolved as a result of selection for force production efficiency. These findings provide further evidence for a degree of uncoupling between form and function in the masticatory system of modern humans. This may reflect the impact of food preparation technologies. These data also support previous suggestions that differences in bite force production efficiency can be considered a spandrel, primarily driven by the midfacial reduction in H. sapiens that occurred for other reasons. Midfacial reduction plausibly resulted in a number of other significant changes in morphology, such as the development of a chin, which has itself been the subject of debate as to whether or not it represents a mechanical adaptation or a spandrel.",
keywords = "Finite element analysis, Homo heidelbergensis, Homo sapiens, Paleoanthropology, Virtual anthropology",
author = "Godinho, {Ricardo Miguel} and Fitton, {Laura C.} and Viviana Toro-Ibacache and Stringer, {Chris B.} and Rodrigo Lacruz and Timothy Bromage and Paul O'Higgins",
year = "2018",
month = "5",
day = "1",
doi = "10.1016/j.jhevol.2018.02.010",
language = "English (US)",
volume = "118",
pages = "56--71",
journal = "Journal of Human Evolution",
issn = "0047-2484",
publisher = "Academic Press Inc.",

}

TY - JOUR

T1 - The biting performance of Homo sapiens and Homo heidelbergensis

AU - Godinho, Ricardo Miguel

AU - Fitton, Laura C.

AU - Toro-Ibacache, Viviana

AU - Stringer, Chris B.

AU - Lacruz, Rodrigo

AU - Bromage, Timothy

AU - O'Higgins, Paul

PY - 2018/5/1

Y1 - 2018/5/1

N2 - Modern humans have smaller faces relative to Middle and Late Pleistocene members of the genus Homo. While facial reduction and differences in shape have been shown to increase biting efficiency in Homo sapiens relative to these hominins, facial size reduction has also been said to decrease our ability to resist masticatory loads. This study compares crania of Homo heidelbergensis and H. sapiens with respect to mechanical advantages of masticatory muscles, force production efficiency, strains experienced by the cranium and modes of deformation during simulated biting. Analyses utilize X-ray computed tomography (CT) scan-based 3D models of a recent modern human and two H. heidelbergensis. While having muscles of similar cross-sectional area to H. heidelbergensis, our results confirm that the modern human masticatory system is more efficient at converting muscle forces into bite forces. Thus, it can produce higher bite forces than Broken Hill for equal muscle input forces. This difference is the result of alterations in relative in and out-lever arm lengths associated with well-known differences in midfacial prognathism. Apparently at odds with this increased efficiency is the finding that the modern human cranium deforms more, resulting in greater strain magnitudes than Broken Hill when biting at the equivalent tooth. Hence, the facial reduction that characterizes modern humans may not have evolved as a result of selection for force production efficiency. These findings provide further evidence for a degree of uncoupling between form and function in the masticatory system of modern humans. This may reflect the impact of food preparation technologies. These data also support previous suggestions that differences in bite force production efficiency can be considered a spandrel, primarily driven by the midfacial reduction in H. sapiens that occurred for other reasons. Midfacial reduction plausibly resulted in a number of other significant changes in morphology, such as the development of a chin, which has itself been the subject of debate as to whether or not it represents a mechanical adaptation or a spandrel.

AB - Modern humans have smaller faces relative to Middle and Late Pleistocene members of the genus Homo. While facial reduction and differences in shape have been shown to increase biting efficiency in Homo sapiens relative to these hominins, facial size reduction has also been said to decrease our ability to resist masticatory loads. This study compares crania of Homo heidelbergensis and H. sapiens with respect to mechanical advantages of masticatory muscles, force production efficiency, strains experienced by the cranium and modes of deformation during simulated biting. Analyses utilize X-ray computed tomography (CT) scan-based 3D models of a recent modern human and two H. heidelbergensis. While having muscles of similar cross-sectional area to H. heidelbergensis, our results confirm that the modern human masticatory system is more efficient at converting muscle forces into bite forces. Thus, it can produce higher bite forces than Broken Hill for equal muscle input forces. This difference is the result of alterations in relative in and out-lever arm lengths associated with well-known differences in midfacial prognathism. Apparently at odds with this increased efficiency is the finding that the modern human cranium deforms more, resulting in greater strain magnitudes than Broken Hill when biting at the equivalent tooth. Hence, the facial reduction that characterizes modern humans may not have evolved as a result of selection for force production efficiency. These findings provide further evidence for a degree of uncoupling between form and function in the masticatory system of modern humans. This may reflect the impact of food preparation technologies. These data also support previous suggestions that differences in bite force production efficiency can be considered a spandrel, primarily driven by the midfacial reduction in H. sapiens that occurred for other reasons. Midfacial reduction plausibly resulted in a number of other significant changes in morphology, such as the development of a chin, which has itself been the subject of debate as to whether or not it represents a mechanical adaptation or a spandrel.

KW - Finite element analysis

KW - Homo heidelbergensis

KW - Homo sapiens

KW - Paleoanthropology

KW - Virtual anthropology

UR - http://www.scopus.com/inward/record.url?scp=85044020461&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85044020461&partnerID=8YFLogxK

U2 - 10.1016/j.jhevol.2018.02.010

DO - 10.1016/j.jhevol.2018.02.010

M3 - Article

C2 - 29606203

AN - SCOPUS:85044020461

VL - 118

SP - 56

EP - 71

JO - Journal of Human Evolution

JF - Journal of Human Evolution

SN - 0047-2484

ER -