Why do we yawn?
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Adrian G. Guggisberg; Johannes Mathis; Armin Schnider; Christian W. Hess
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Article
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2010
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Elsevier Science
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English
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Yawning is a phylogenetically old behaviour that can be observed in most vertebrate species from foetal stages to old age. The origin and function of this conspicuous phenomenon have been subject to speculations for centuries. Here, we review the experimental evidence for each of these hypotheses. I