Put your hand in front of your mouth! Why do we yawn?

psychoSoph002 Full Comic english

You won’t believe how often I yawned while reading for, writing and drawing this chapter! It seemed yawning was contagious on me even without any social cue! 😉

Perhaps you are as surprised as I am that the idea around blood oxygenation is this old. Indeed, the dutch doctor Johannes de Gorter assumed that yawning causes blood to flow faster and accumulate in the brain in his book De Perspiratione insensibili (1725, cited from Walusinski, 2013). From this the oxygenation hypothesis was developed which held up for over two centuries.


  1. Baenninger, R. (1997). On yawning and its functions.
  2. Eguibar, J. R., Uribe, C. A., Cortes, C., Bautista, A., & Gallup, A. C. (2017). Yawning reduces facial temperature in the high-yawning subline of Sprague-Dawley rats.
  3. Gallup, A. C., & Gallup, G. G. (2007). Yawning as a Brain Cooling Mechanism: Nasal Breathing and Forehead Cooling Diminish the Incidence of Contagious Yawning.
  4. Gallup, A. C., & Gallup, G. G. (2008). Yawning and thermoregulation.
  5. Gallup, A. C., & Hack, G. D. (2011). Human paranasal sinuses and selective brain cooling: A ventilation system activated by yawning?.
  6. Guggisberg, A. G., Mathis, J., & Hess, C. W. (2010). Interplay between yawning and vigilance: A review of the experimental evidence.
  7. Guggisberg, A. G., Mathis, J., Schnider, A., & Hess, C. W. (2010). Why do we yawn?.
  8. Hinchliff, C. E., Smith, S. A., Allman, J. F., Burleigh, J. G., Chaudhary, R., Coghill, L. M., Crandall, K. A., Deng, J., Drew, B. T., Gazis, R., Gude, K., Hibbett, D. S., Katz, L. A., Laughinghouse, H. D., McTavish, E. J., Midford, P. E., Owen, C. L., Ree, R. H., Rees, J. A., … Cranston, K. A. (2015). Synthesis of phylogeny and taxonomy into a comprehensive tree of life.
  9. Massen, J. J. M., & Gallup, A. C. (2017). Why contagious yawning does not (yet) equate to empathy.
  10. Platek, S. M., Mohamed, F. B., & Gallup, G. G. (2005). Contagious yawning and the brain.
  11. Provine, R. R., Tate, B. C., & Geldmacher, L. L. (1987). Yawning: No effect of 3–5% CO2, 100% O2, and exercise.
  12. Schürmann, M., Hesse, M. D., Stephan, K. E., Saarela, M., Zilles, K., Hari, R., & Fink, G. R. (2005). Yearning to yawn: The neural basis of contagious yawning.
  13. Senju, A. (2010). Developmental and comparative perspectives of contagious yawning.
  14. Walusinski, O. (2013). Why Do We Yawn? Past and Current Hypotheses.