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A unifying model for timing of walking onset in humans and other mammals.

Garwicz, Martin LU ; Christensson, Maria LU and Psouni, Elia LU (2009) In Proceedings of the National Academy of Sciences 106. p.21889-21893
Abstract
The onset of walking is a fundamental milestone in motor development of humans and other mammals, yet little is known about what factors determine its timing. Hoofed animals start walking within hours after birth, rodents and small carnivores require days or weeks, and nonhuman primates take months and humans approximately a year to achieve this locomotor skill. Here we show that a key to the explanation for these differences is that time to the onset of walking counts from conception and not from birth, indicating that mechanisms underlying motor development constitute a functional continuum from pre- to postnatal life. In a multiple-regression model encompassing 24 species representative of 11 extant orders of placental mammals that... (More)
The onset of walking is a fundamental milestone in motor development of humans and other mammals, yet little is known about what factors determine its timing. Hoofed animals start walking within hours after birth, rodents and small carnivores require days or weeks, and nonhuman primates take months and humans approximately a year to achieve this locomotor skill. Here we show that a key to the explanation for these differences is that time to the onset of walking counts from conception and not from birth, indicating that mechanisms underlying motor development constitute a functional continuum from pre- to postnatal life. In a multiple-regression model encompassing 24 species representative of 11 extant orders of placental mammals that habitually walk on the ground, including humans, adult brain mass accounted for 94% of variance in time to walking onset postconception. A dichotomous variable reflecting species differences in functional limb anatomy accounted for another 3.8% of variance. The model predicted the timing of walking onset in humans with high accuracy, showing that this milestone in human motor development occurs no later than expected given the mass of the adult human brain, which in turn reflects the duration of its ontogenetic development. The timing of motor development appears to be highly conserved in mammalian evolution as the ancestors of some of the species in the sample presented here diverged in phylogenesis as long as 100 million years ago. Fundamental patterns of early human life history may therefore have evolved before the evolution of primates. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Proceedings of the National Academy of Sciences
volume
106
pages
21889 - 21893
publisher
National Acad Sciences
external identifiers
  • wos:000272994200077
  • pmid:20018704
  • scopus:76049097100
ISSN
1091-6490
DOI
10.1073/pnas.0905777106
language
English
LU publication?
yes
id
c39c6214-b1ae-4d25-8f65-63f65907c896 (old id 1523524)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/20018704?dopt=Abstract
date added to LUP
2010-01-12 12:51:09
date last changed
2017-08-27 05:48:10
@article{c39c6214-b1ae-4d25-8f65-63f65907c896,
  abstract     = {The onset of walking is a fundamental milestone in motor development of humans and other mammals, yet little is known about what factors determine its timing. Hoofed animals start walking within hours after birth, rodents and small carnivores require days or weeks, and nonhuman primates take months and humans approximately a year to achieve this locomotor skill. Here we show that a key to the explanation for these differences is that time to the onset of walking counts from conception and not from birth, indicating that mechanisms underlying motor development constitute a functional continuum from pre- to postnatal life. In a multiple-regression model encompassing 24 species representative of 11 extant orders of placental mammals that habitually walk on the ground, including humans, adult brain mass accounted for 94% of variance in time to walking onset postconception. A dichotomous variable reflecting species differences in functional limb anatomy accounted for another 3.8% of variance. The model predicted the timing of walking onset in humans with high accuracy, showing that this milestone in human motor development occurs no later than expected given the mass of the adult human brain, which in turn reflects the duration of its ontogenetic development. The timing of motor development appears to be highly conserved in mammalian evolution as the ancestors of some of the species in the sample presented here diverged in phylogenesis as long as 100 million years ago. Fundamental patterns of early human life history may therefore have evolved before the evolution of primates.},
  author       = {Garwicz, Martin and Christensson, Maria and Psouni, Elia},
  issn         = {1091-6490},
  language     = {eng},
  pages        = {21889--21893},
  publisher    = {National Acad Sciences},
  series       = {Proceedings of the National Academy of Sciences},
  title        = {A unifying model for timing of walking onset in humans and other mammals.},
  url          = {http://dx.doi.org/10.1073/pnas.0905777106},
  volume       = {106},
  year         = {2009},
}