David R. Samson, Ph.D.

Research Statement: I investigate the link between sleep, health, and cognition in human and non-human primates

Humans are a remarkable species. We live in large social networks, persist in inhospitable places, fashion complex tools, and communicate using language. While we exhibit many morphological and behavioral differences to other primates – our cognitive capacity likely played a crucial role in our success. My research investigates the biology, ecology, and evolution of primate sleep. I believe the effects of sleep on our lineage were profound. For example, in humans, sleep is critical for immune strength, working memory, attention, decision-making, and visual-motor performance, yet how sleep affects such processes remains unknown for most non-human primates. To investigate this research question, I use pioneering, non-invasive technology to study human and non-human primates with a broad phylogenetic scope. In addition, I engage with the emerging field of evolutionary medicine by using my findings to understand human sleep disorders within an evolutionary framework. The ultimate goal of my research is to further our understanding of human evolution.



  • Samson, D.R., Vining, A., C.L. Nunn. 2019. Sleep influences cognitive performance in lemurs. Animal Cognition. DOI: 10.1007/s10071-019-01266-1 [PDF]
  • Nunn, C.N., and D.R. Samson. 2019. Do We Sleep Better Than Our Ancestors? This View of Life: Evolutionary Mismatch Series
  • Samson, D.R., Crittenden, A.N., Mabulla, I.A., Mabulla, A.Z.P. and C.L. Nunn. 2018. Does the moon influence sleep in small-scale societies? Sleep Health. 4: 509-514. DOI: 10.1016/j.sleh.2018.08.004 [PDF]
  • Yetish, G., and Samson, D.R. 2018. Sleep research in non-Western populations reveals novel insights about the breadth and diversity of human sleep patterns. Sleep Health. 4: 495-496. DOI: 10.1016/j.sleh.2018.10.1006 [PDF]
  • Manus, M.B., Bloomfield, G.S., Leonard, A.S., Guidera, L.N., Samson, D.R., C.N. Nunn. 2018. High prevalence of hypertension in an agricultural village in Madagascar. PLOS ONE. 13: e0201616. DOI: 10.1371/journal.pone.0201616 [PDF]
  • Crittenden, A.N., Samson, D.R., Herlosky, K.N., Mabulla, I.A., Mabulla, A.Z.P. and J.J. McKenna. 2018. Infant co-sleeping patterns and maternal sleep quality among Hadza hunter-gatherers. Sleep Health. 4: 527-534. DOI: 10.1016/j.sleh.2018.10.005 [PDF]
  • Samson, D.R., J. Bray, and C.L. Nunn. 2018. The cost of deep sleep: Environmental influences on sleep regulation are greater for diurnal lemurs. American Journal of Physical Anthropology. 166: 578-589. DOI: 10.1002/ajpa.23455 [PDF]
  • Nunn, C.L., and D.R. Samson. 2018. Sleep in a comparative context: Investigating how human sleep differs from sleep in other primates. American Journal of Physical Anthropology. 166: 601-612. DOI: 1002/ajpa.23427 [PDF]
  • Samson, D.R., A.N. Crittenden, I.A. Mabulla, and A.Z.P. Mabulla. 2017. The evolution of human sleep: Technological and cultural innovation associated with sleep-wake regulation among Hadza hunter-gatherers. Journal of Human Evolution 113: 91-102 [PDF]
  • Samson, D.R., A.N. Crittenden, I.A. Mabulla, A.Z.P. Mabulla, and C.L. Nunn. 2017. Chronotype variation drives night-time sentinel-like behaviour in hunter-gatherers. Royal Soceity Proceedings B 284: 20170967 [PDF]
  • Samson, D.R., A.N. Crittenden, I.A. Mabulla, A.Z.P. Mabulla, and C.L. Nunn. 2017. Hadza sleep biology: evidence for flexible sleep-wake patterns in hunter-gatherers. American Journal of Physical Anthropology 162: 573-582 [PDF]
  • Samson, D.R., M. Manus, A.D. Krystal, E. Fakir, J.J. Yu, and C.L. Nunn. 2017. Segmented sleep in a nonelectric, small-scale agricultural society in Madagascar. American Journal of Human Biology 29: e22979 [PDF]
  • Bray, J., D.R. Samson, and C.L. Nunn. 2017. Activity patterns in seven captive lemur species: evidence for cathemerality in Varecia and Lemur catta? American Journal of Primatology 79: e22648 [PDF]
  • Samson, D.R., G.M. Yetish, A.N. Crittenden, I.A. Mabulla, A.Z.P. Mabulla, and C.L. Nunn. 2016. What is segmented sleep? Actigraphy field validation for daytime sleep and nighttime wake. Sleep Health 2: 341-347 [PDF]
  • Nunn, C.L., D.R. Samson, and A.D. Krystal. 2016. Shining evolutionary light on human sleep and sleep disorders. Evolution, Medicine, and Public Health 1: 227-243 [PDF]
  • Samson, D.R. and C.L. Nunn. 2015. Sleep intensity and the evolution of human cognition. Evolutionary Anthropology 24(6): 225-237 [PDF]
  • Samson, D.R. and R.W. Shumaker. 2015. Pre-sleep and sleeping platform construction behavior in captive orangutans (Pongo spp.): Implications for ape health and welfare. Folia Primatologica 86(3): 187–202 [PDF]
  • Samson, D.R. and R.W. Shumaker. 2015. Orangutans (Pongo spp.) have deeper, more efficient sleep than baboons (Papio papio) in captivity. American Journal of Physical Anthropology 157(3): 412–427 [PDF]
  • Samson, D.R. and K.D. Hunt. 2014. Is chimpanzee (Pan troglodytes schweinfurthii) low population density linked with low levels of aggression? Pan Africa News 21: 15–17 [PDF]
  • Samson, D.R., D. Hurst, and R.W. Shumaker. 2014. Orangutan night-time long call behavior: Sleep quality costs associated with vocalizations in captive Pongo. Advances in Zoology 1: 1–8 [PDF]
  • Samson, D.R. and K. D. Hunt. 2014. Chimpanzees preferentially select sleeping platform construction tree species with biomechanical properties that yield stable, firm, but compliant nests. PLOS ONE 9: 1–8 [PDF]
  • Samson, D.R. and R.W. Shumaker. 2013. Documenting orangutan sleep architecture: sleeping platform complexity increases sleep quality in captive Pongo. Behaviour 150: 845–861 [PDF]
  • Samson, D.R., M.P. Muehlenbein, and K.D. Hunt. 2012. Do chimpanzees (Pan troglodytes schweinfurthii) exhibit sleep related behaviors that minimize exposure to parasitic arthropods? A preliminary report on the possible anti-vector function of chimpanzee sleeping platforms. Primates 54(1): 73–80 [PDF]
  • Samson, D.R. 2012. The chimpanzee nest quantified: Morphology and ecology of arboreal sleeping platforms within the dry habitat site of Toro-Semliki Wildlife Reserve, Uganda. Primates 53(4): 357–364 [PDF]
  • Samson, D.R. and K.D. Hunt. 2012. A thermodynamic comparison of arboreal and terrestrial sleeping sites for dry-habitat chimpanzees (Pan troglodytes schweinfurthii) at the Toro-Semliki Wildlife Reserve, Uganda. American Journal of Primatology 74(9): 811–818 [PDF]
  • Husmann, P.R. and D.R. Samson. 2011. In the eye of the beholder: Sex and race determination using the human orbital aperture. Journal of Forensic Sciences 56(6): 1424–1429 [PDF]
  • Samson, D.R.. 2006. Stones of contention: The Acheulean handaxe lethal projectile controversy. Lithic Technology 31(2): 127–136 [PDF]

Selected Published Journals

Curriculum Vitae



Dr. David Samson Joins UTM Anthropology

David Samson interviewed on TVO's The Agenda with Steve Paikin

Dr. David Samson named "The Evolutionist" in Van Winkle's "15 Most Interesting People in Sleep" by Theresa Fisher

BBC News: Lark or night owl? Blame your ancestors ~ By Helen Briggs

The Toronto Star: Having trouble sleeping? Blame evolution, study says ~ By Scott Wheeler

New York Times: Down from the trees, humans finally got a decent night's sleep ~ By Carl Zimmer

Time: Humans sleep less than closely-ralated mammals ~ By Victor Luckerson

    Research Featured By:

Featured articles

Discover: How Our Sleeping Habits Helped to Make Us Human ~ By Bridget Alex

GQ: Why Am I So Tired All the Time? ~ By Alex Shultz

Seeker: How Human Sleep Differs From Other Primates, and What It Means for Our Health ~ By Jen Viegas

New York Times: Living another day, thanks to grandparents who couldn't sleep ~ By Aneri Pattani

New Scientist: Sleeping less in old age may be adaptation to survive in wild ~ By Linda Geddes

Popular Science: Grandma's insomnia might be a product of evolution ~ By Aparna Nathan

University of Toronto News: Why your teen stays up late, you sleep pourly - new research confirms 'sentinel theory' ~ By Nicolle Wahl

Seeker: Trouble sleeping? Restless nights evolved from ancestors avoiding dangers ~ By Jen Viegas

The Sydney Morning Herald: Early birds, night owls and wakeful elderly people - why we sleep when we do ~ By Melissa Cunningham

The Guardian: Restless development - bad sleep may be evolutionary survival tool, study finds ~ By Hannah Devlin

United Kingdom The Telegraph: Revealed - Why we lose sleep as we grow older ~ By Sarah Knapton

UNLV News Center: Sleep elusive? New study shows there's a reason for that ~ By Francis McCabe

Duke Today: Live-in grandparents helped human ancestors get a safer night's sleep ~ By Robin Smith

Huffington Post: People who live without screens don't sleep any better than the rest of us ~ By Sarah DiGiulio

Duke Today: People far from urban lights, bright screens still skimp on sleep ~ By Robin Smith

Science News: Snooze patterns vary across cultures, opening eyes to evolution of sleep ~ By Bruce Bower

Welt (Germany): Schlafstörungen? Kennen manche Völker gar nicht ~ By Von Wiebke Hollersen

The Washington Post: How climbing down from tress let humans finally get a good night's sleep ~ By Sarah Kaplan

BBC: Why humans need less lseep than any other primate ~ By Melissa Hogenboom

BBC Earth: Apes reveal secrets to good sleep ~ By Matt Walker

National Geographic: Chimpanzees make beds that offer them best night's sleep ~ By Christine Dell'Amore

New York Times: Chimps are particular about where they rest ~ Observatory

Smithsonian: Chimpanzees sleep in trees to escape the humidity ~ By Erin Wayman

Featured interviews

BBC "CrowdScience": Why are there morning people and night people? ~ Produced by Cathy Edwards and presented by Anand Jagitia

Reuters Editor's Pick: Our sleep patterns inherited from hunter-gatherers, says study ~ Producsed by Jim Drury

BBC World Service "The Inquiry": Have we always felt this tired? ~ Presented by James Fletcher

NPR "The Pulse": Sleep habits may have helped humans brach off from other primates ~ Presented by Max Green

ABC Radio Sydney "Breakfast": Dr. David Samson is working to unravel the evolutionary reasons behind our mismatched sleep patterns ~ Hosted by Robbie Buck

Calgary AM: Age and sleep ~ Hosted by Danielle Smith

HumanOS Radio: Professor David Samson on bedding, sleep depth, and cognition ~ By Dan Pardi

Featured presentations

Panel: Hacking the Brain

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  • Washington, D.C., Grosvenor Auditorium: Sleep and the Primate Mind