// Workers AI · dad joke modeWhat did "Touching heads" say to itself? You're always on the same wavelength.
 | The examples and perspectives in this article may not represent a worldwide view of the subject. The specific issue is: definitely not all cultures touch heads. in some places, "touching heads" is just weird. (March 2016) |
Touching heads is an emotional expression.
It is absent in other apes, though they tend to use the same bodily expressions of emotions like humans.[1] A 2012 study claimed that this behavior likely evolved in humans to share head lice among friends and relatives. Head lice infestations might serve as a protection against body lice by inducing cross-resistance. This can be adaptive because only the latter type of lice transmit potentially lethal human pathogens.[2]
References
[edit]- ↑ Darwin Charles (1998) The Expression of the Emotions in Man and Animals, 3rd edn, London: Harper Collins.
- ↑ Rozsa L, Apari P (2012). "Why infest the loved ones – inherent human behaviour indicates former mutualism with head lice" (PDF). Parasitology. 139: 696–700. doi:10.1017/s0031182012000017. PMID 22309598.
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