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Paleoclimatic Variation and Brain Expansion during Human Evolution

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Abstract

One of the major adaptations during the evolution of Homo sapiens was an increase in brain size. Here we present evidence that a significant and substantial proportion of variation in brain size may be related to changes in temperature. Based on a sample of 109 fossilized hominid skulls, we found that cranial capacities were highly correlated with paleoclimatic changes in temperature, as indexed by oxygen isotope data and sea-surface temperature. Indeed, as much as 52% of the variance in the cranial capacity of these skulls could be accounted for by temperature variation at 100 ka intervals. As an index of more short-term seasonal fluctuations in temperature, we examined the latitude of the sites from which the crania originated. More than 22% of the variance in cranial capacity of these skulls could be accounted for by variation in equatorial distance.

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Authors and Affiliations

  1. Department of Psychology, University at Albany, State University of New York, 1400 Washington Ave., Albany, NY, 12222, USA

    Jessica Ash & Gordon G. Gallup Jr.

Authors
  1. Jessica Ash
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  2. Gordon G. Gallup Jr.
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Correspondence to Gordon G. Gallup Jr..

Appendix

Appendix

Fossil information

Number

Fossil

Taxon†

Capacity (cc)

Date (Ma)

1

SK 47 (adult)

Early h

595.000a

1.900a

2

Stw 53

Early h

570.000a

1.900a

3

SK 847

h, hh/he

507.000a

1.900a

4

SK 27

h

475.000a

1.900a

5

KNM-ER 1470 (Koobi Fora)

hher

776.000a

1.890a

6

KNM-ER 3732 (Koobi Fora)

hher

622.500a

1.890a

7

KNM-ER 1813 (Koobi Fora)

hh

506.333a

1.890a

8

Omo L894-1

h

500.000a

1.890a

9

Dmansi 2280

hh

775.000b

1.860b

10

Dmansi 2282

hh

650.000b

1.860b

11

Dmansi 2700

hh

600.000c

1.860b

12

KNM-ER 1590 (Koobi Fora)

hr

782.500a

1.850a

13

KNM-ER 1805 (Koobi Fora)

hh

616.000a

1.850a

14

Modjokerto (adult)

he

855.000a

1.800a

15

OH 24 (Olduvai)

hh

597.000d

1.800a

16

KNM-ER 3733 (Koobi Fora)

hher

825.400a

1.780a

17

OH 7 (adult) (Olduvai)

hh

674.000a

1.780a

18

OH 16 (adult) (Olduvai)

hh

639.200a

1.670a

19

Sangiran 4

he

856.000a

1.660a

20

OH 13 (adult) (Olduvai)

hh

662.286a

1.660a

21

Sangiran 31

he

1,000.000a

1.660a

22

KNM-WT 15000 (adult) (Nariokotome)

he

904.500a

1.600a

23

KNM-ER 3883 (Koobi Fora)

hher

825.667a

1.570a

24

Sangiran 12

he

951.000a

1.25

25

Sangiran 3 (adult)

he

900.000a

1.25

26

Sangiran 10

he

868.600a

1.25

27

Sangiran 9

he

856.000a

1.25

28

Sangiran 2

he

792.571a

1.25

29

Sangiran 17

he

1,020.000a

1.25

30

OH 9 (Olduvai)

he

1,070.500a

1.200a

31

Gongwangling 1

he

779.000a

1.150a

32

Buia

he

800.000a

1.000a

33

Trinil 2

he

940.000a

0.900a

34

Ceprano

hhei

1,185.000a

0.850k

35

OH 12 (Olduvai)

he

732.330a

0.840a

36

Ternifine

ahs

1,300.000a

0.750a

37

Bodo

hhei

1,250.000f

0.600f

38

Nanjing

he

1,000.000c

0.600c

39

Atapuerca 4 (AT 600)

hant

1,390.000a

0.500g

40

Atapuerca 6 (11- to 14-year-old)

hant

1,153.333a

0.500g

41

Atapuerca 5 (AT 700)

hant

1,125.000a

0.500g

42

Sambungmacan 1

he

1,056.333a

0.500a

43

Salé 1

he

911.000a

0.400a

44

Araho 21

hhei

1,138.667a

0.400a

45

Broken hill 1 (Kabwe)

hhei

1,310.000a

0.350a

46

Saldanha 1 (Elandsfontein)

hhei

1,216.667a

0.350a

47

Yunxian

he

1,100.000a

0.350a

48

Ndutu 1

ahs

1,100.000a

0.350a

49

Petralona 1

hhei

1,266.556a

0.325a

50

Reilingn

hhei

1,432.000a

0.300a

51

Swanscombe 1

hhei

1,305.000a

0.300a

52

Narmada 1

he

1,249.333a

0.300a

53

Steinheim 1

hhei

1,111.192a

0.300a

54

Florisbad 1

ahs

1,280.000a

0.279h

55

KNM-ER 3884

ahs

1,400.000a

0.270a

56

Ngawi

he

1,000.000c

0.250c

57

Hexian

he

1,012.500a

0.250a

58

Zhoukoudian (III)

he

937.500a

0.210i

59

Zhoukoudian (VI)

he

850.000a

0.210i

60

Zhoukoudian L1 (X)

he

1,225.000a

0.210i

61

Zhoukoudian h3 (V)

he

1,220.000a

0.210i

62

Zhoukoudian D1 (II)

he

1,030.000a

0.210i

63

Zhoukoudian L3 (XII)

he

1,030.000a

0.210i

64

Zhoukoudian L2 (XI)

he

1,015.000a

0.210i

65

Dali 1

ahs

1,160.000a

0.205a

66

Ehrinhsdorf 9

hhei

1,450.000a

0.203a

67

Sambungmacan 3

he

900.000a

0.200a

68

Solo 5, Ngandong V

he

1,266.167a

0.200a

69

Solo 9, Ngandong IX

he

1,135.000a

0.200a

70

Solo 1, Ngandong I

he

1,121.429a

0.200a

71

Solo 6, Ngandong VI

he

1,115.714a

0.200a

72

Solo 10, Ngandong X

he

1,109.000a

0.200a

73

Omo 2

ahs

1,432.500a

0.195j

74

Jinniushan

he

1,316.667a

0.187a

75

Vértesszöllös 2

ahs

1,334.571a

0.186a

76

Biache

hhei

1,200.000a

0.178a

77

Fontéchevade 2

hn

1,420.000a

0.160a

78

La Chaise

hn

1,065.000a

0.151a

79

Singa 1

hn

1,550.000a

0.150a

80

KNM-ES-11693 (Eliye Springs)

ahs

1,375.000a

0.150a

81

Jebel Irhoud 2

hn

1,400.000l

0.140a

82

Jebel Irhoud 1

hn

1,305.000l

0.140a

83

Krapina-D

hn

1,450.000a

0.130a

84

Krapina 3

hn

1,200.000a

0.130a

85

Ngaloba

ahs

1,283.500a

0.125a

86

Daka (BOU VP-2/66)

he

995.000c

0.100c

87

Saccopastore 2

hn

1,295.000a

0.100a

88

Tabun C1

hn

1,270.500a

0.100a

89

Saccopastore 1

hn

1,234.333a

0.100a

90

Skhul 9

hn

1,587.333a

0.090a

91

Skhul 4

hn

1,554.500a

0.090a

92

Skhul 5

hn

1,499.500a

0.090a

93

Skhul 2

hn

1,300.000a

0.090a

94

La Ferrassie 1

hn

1,650.200a

0.068a

95

Teshik-Tash (adult)

hn

1,581.000a

0.060a

96

Gibraltar 1 (Forbes’ Quarry)

hn

1,226.750a

0.060a

97

Monte Circeo I

hn

1,551.000a

0.055a

98

Amud 1

hn

1,745.000a

0.051a

99

Shanidar 1

hn

1,650.000a

0.050a

100

La Chapelle-aux-Saints

hn

1,626.000a

0.050a

101

Shanidar 5

hn

1,550.000a

0.050a

102

Spy 2

hn

1,487.400a

0.050a

103

Spy 1

hn

1,457.500a

0.050a

104

La Quina 5

hn

1,345.250a

0.050a

105

Neandertal 1

hn

1,337.750a

0.050a

106

Ganovce 1

hn

1,320.000a

0.050a

107

Le Moustier 1

hn

1,486.200a

0.040a

108

Galilee

ahs

1,400.000a

0.040a

109

Eyasi

ahs

1,235.000a

0.035a

  1. †Legend for taxa:
  2. ahs: Archaic Homo sapiens
  3. h: Homo
  4. hant: Homo antecessor
  5. he: Homo erectus
  6. hher: Homo ergaster
  7. hh: Homo habilis
  8. hhei: Homo heidelbergensis
  9. hn: Neandertal
  10.  
  11. References:
  12. aDe Miguel and Henneberg (2001)
  13. bLee (2005)
  14. cLee and Wolpoff (2003)
  15. dTobias (1991)
  16. eLarick et al. (2001)
  17. fConroy et al. (2000)
  18. gBischoff and Shamp (2003)
  19. hKunman et al. (1999)
  20. iShen et al. (2004)
  21. jMcDougall et al. (2005)
  22. kBruner and Manzi (2005)
  23. lHolloway et al. (2004)

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Ash, J., Gallup, G.G. Paleoclimatic Variation and Brain Expansion during Human Evolution. Hum Nat 18, 109–124 (2007). https://doi.org/10.1007/s12110-007-9015-z

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