The Science Behind
the Staircase
249+ peer-reviewed sources from evolutionary biology, medicine, nutrition, neuroscience, and beyond. Every claim in the book traces back here.
Browse by Topic
Publication Timeline
National Vital Statistics Reports: Births.
Centers for Disease Control and Prevention
The Anxious Generation: How the Great Rewiring of Childhood Is Causing an Epidemic of Mental Illness
Penguin Press
Global, regional, and national burden of low back pain, 1990-2020.
The Lancet Rheumatology
Our Epidemic of Loneliness and Isolation: The U.S. Surgeon General's Advisory on the Healing Effects of Social Connection and Community
U.S. Department of Health and Human Services
Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected worldwide in the 20th and 21st centuries.
Human Reproduction Update
Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts.
The Lancet Public Health
The Common Sense Census: Media Use by Tweens and Teens
Common Sense Media
The state of American friendship: change, challenges, and loss.
Survey Center on American Life, American Enterprise Institute
Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race
Scribner
Guideline for the pharmacological treatment of hypertension in adults
World Health Organization
Potassium intake and blood pressure: a dose-response meta-analysis of randomized controlled trials.
Journal of the American Heart Association
Glacial cooling and climate sensitivity revisited.
Nature
World Cancer Report: Cancer Research for Cancer Prevention
International Agency for Research on Cancer, World Health Organization
Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis.
The Lancet Respiratory Medicine
Sarcopenia: revised European consensus on definition and diagnosis.
Age and Ageing
Close social relationships correlate with human gut microbiota composition.
Scientific Reports
Urban nature experiences reduce stress in the context of daily life based on salivary biomarkers.
Frontiers in Psychology
Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake.
Cell Metabolism
Association of step volume and intensity with all-cause mortality in older women.
JAMA Internal Medicine
Bidirectional relationship of stress and affect with physical activity and healthy eating.
British Journal of Health Psychology
Vulnerability of the industrialized microbiota.
Science
Breath of life: the respiratory vagal stimulation model of contemplative activity.
Frontiers in Human Neuroscience
Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing.
JAMA Network Open
Hunter-gatherer energetics and human obesity.
PLoS ONE
Ultra-processed food consumption and chronic non-communicable diseases-related dietary nutrient profile in the UK.
Nutrients
Associations between screen time and lower psychological well-being among children and adolescents: evidence from a population-based study.
Preventive Medicine Reports
Sean Parker unloads on Facebook: 'God only knows what it's doing to our children's brains.'
Axios
A bayesian mixed methods analysis of basic psychological needs satisfaction through outdoor learning and its influence on motivational regulations in science education.
Frontiers in Psychology
Breaking bread: the functions of social eating.
Adaptive Human Behavior and Physiology
New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens.
Nature
Coronary atherosclerosis in indigenous South American Tsimane: a cross-sectional cohort study.
The Lancet
Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men.
Age and Ageing
Temporal trends in sperm count: a systematic review and meta-regression analysis.
Human Reproduction Update
Seasonal cycling in the gut microbiome of the Hadza hunter-gatherers of Tanzania.
Science
Relation between resting amygdalar activity and cardiovascular events: a longitudinal and cohort study.
The Lancet
The effect of cold showering on health and work: a randomized controlled trial.
PLoS ONE
On orthorexia nervosa: a review of the literature and proposed diagnostic criteria.
Eating Behaviors
How colonization by microbiota in early life shapes the immune system.
Science
Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study.
BMJ Open
Cospeciation of gut microbiota with hominids.
Science
Metabolic acceleration and the evolution of human brain size and life history.
Nature
Incidence of anterior cruciate ligament tears and reconstruction: a 21-year population-based study.
American Journal of Sports Medicine
Revised estimates for the number of human and bacteria cells in the body.
Cell
Diet-induced extinctions in the gut microbiota compound over generations.
Nature
Innate immunity and asthma risk in Amish and Hutterite farm children.
New England Journal of Medicine
Influence of body position on defecation in humans.
Lower Urinary Tract Symptoms
Fermented foods in a global age: East meets West.
Comprehensive Reviews in Food Science and Food Safety
Loneliness and risk of cardiovascular disease: systematic review and meta-analysis of longitudinal observational studies.
Heart
The growing burden of invasive melanoma: projections of incidence rates and numbers of new cases in six susceptible populations through 2031.
Journal of Investigative Dermatology
Loneliness and implicit attention to social threat: a high-performance electrical neuroimaging study.
Cognitive Neuroscience
Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness.
PNAS
The evolution of prolonged life after reproduction.
Trends in Ecology and Evolution
Position of the Academy of Nutrition and Dietetics: health implications of dietary fiber.
Journal of the Academy of Nutrition and Dietetics
Promoting health and longevity through diet: from model organisms to humans.
Cell
Greenlandic Inuit show genetic signatures of diet and climate adaptation.
Science
Effect of time spent outdoors at school on the development of myopia among children in China: a randomized clinical trial.
JAMA
Association between sauna bathing and fatal cardiovascular and all-cause mortality events.
JAMA Internal Medicine
The ancestral shape hypothesis: an evolutionary explanation for the occurrence of intervertebral disc herniation in humans.
BMC Evolutionary Biology
Green areas around homes reduce atopic sensitization in children.
Allergy
Gracility of the modern Homo sapiens skeleton is the result of decreased biomechanical loading.
PNAS
Sleep intensity and the evolution of human cognition.
Evolutionary Anthropology
Natural sleep and its seasonal variations in three pre-industrial societies.
Current Biology
Mistimed sleep disrupts circadian regulation of the human transcriptome.
PNAS
Brown adipose tissue improves whole-body glucose homeostasis and insulin sensitivity in humans.
Diabetes
Diet rapidly and reproducibly alters the human gut microbiome.
Nature
Transgenerational epigenetic inheritance: myths and mechanisms.
Cell
Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA.
Nature
Structure and function of the hearts of lizards and snakes.
Biological Reviews
Natural selection and infectious disease in human populations.
Nature Reviews Genetics
Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans.
Diabetes
Sea level and global ice volumes from the Last Glacial Maximum to the Holocene.
PNAS
Stimulation of systemic low-grade inflammation by psychosocial stress.
Psychosomatic Medicine
Daylight saving time and myocardial infarction.
Open Heart
Gut microbiome of the Hadza hunter-gatherers.
Nature Communications
Influences of maternal and paternal PTSD on epigenetic regulation of the glucocorticoid receptor gene in Holocaust survivor offspring.
American Journal of Psychiatry
An evolutionary perspective on food and human taste.
Current Biology
Whatever next? Predictive brains, situated agents, and the future of cognitive science.
Behavioral and Brain Sciences
An updated view on the role of dopamine in myopia.
Experimental Eye Research
Free to Learn: Why Unleashing the Instinct to Play Will Make Our Children Happier, More Self-Reliant, and Better Students for Life
Basic Books
Pediatric obstructive sleep apnea and the critical role of oral-facial growth: evidences.
Frontiers in Neurology
The Story of the Human Body: Evolution, Health, and Disease
Pantheon
Epigenetic regulation on gene expression induced by physical exercise.
Journal of Musculoskeletal and Neuronal Interactions
The oldest known primate skeleton and early haplorhine evolution.
Nature
Regulation of the immune system by biodiversity from the natural environment: an ecosystem service essential to health.
PNAS
Structure and function of the human skin microbiome.
Trends in Microbiology
Effects of mindfulness meditation on serum cortisol of medical students.
Journal of the Medical Association of Thailand
Entrainment of the human circadian clock to the natural light-dark cycle.
Current Biology
Sleep drives metabolite clearance from the adult brain.
Science
Recruited brown adipose tissue as an antiobesity agent in humans.
Journal of Clinical Investigation
Human milk oligosaccharides: every baby needs a sugar mama.
Glycobiology
Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk.
PNAS
Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour.
Nature Reviews Neuroscience
The migrating motor complex: control mechanisms and its role in health and disease.
Nature Reviews Gastroenterology and Hepatology
Breaking up prolonged sitting reduces postprandial glucose and insulin responses.
Diabetes Care
Metabolic hypothesis for human altriciality.
PNAS
Environmental biodiversity, human microbiota, and allergy are interrelated.
PNAS
Brain-to-brain coupling: a mechanism for creating and sharing a social world.
Trends in Cognitive Sciences
A systematic review of the global prevalence of low back pain.
Arthritis and Rheumatism
Rest is not idleness: implications of the brain's default mode for human development and education.
Perspectives on Psychological Science
Prevalence of myopia and its association with body stature and educational level in 19-year-old male conscripts in Seoul, South Korea.
Investigative Ophthalmology and Visual Science
Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy.
The Lancet
Myopia.
The Lancet
Effects of thermal environment on sleep and circadian rhythm.
Journal of Physiological Anthropology
Body size, size variation, and sexual size dimorphism in early Homo.
Current Anthropology
Metabolic physiology of dinosaurs and early birds.
The Complete Dinosaur, Indiana University Press
Addiction by Design: Machine Gambling in Las Vegas
Princeton University Press
Cognitive reserve in ageing and Alzheimer's disease.
The Lancet Neurology
Human gut microbiome viewed across age and geography.
Nature
Exposure to environmental microorganisms and childhood asthma.
New England Journal of Medicine
Prevalence and correlates of vitamin D deficiency in US adults.
Nutrition Research
The decline of play and the rise of psychopathology in children and adolescents.
American Journal of Play
The skin microbiome.
Nature Reviews Microbiology
Population genetics of malaria resistance in humans.
Heredity
Tenfold population increase in Western Europe at the Neandertal-to-modern human transition.
Science
Supernormal Stimuli: How Primal Urges Overran Their Evolutionary Purpose
W.W. Norton
Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns.
PNAS
Touch for socioemotional and physical well-being: a review.
Developmental Review
Origin and evolution of the adaptive immune system: genetic events and selective pressures.
Nature Reviews Genetics
The nocturnal bottleneck and the evolution of mammalian vision.
Brain, Behavior and Evolution
Social relationships and mortality risk: a meta-analytic review.
PLoS Medicine
Effect of forest bathing trips on human immune function.
Environmental Health and Preventive Medicine
Induction of epigenetic alterations by dietary and other environmental factors.
Advances in Genetics
Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis.
Nature Communications
Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly.
Bone
The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary.
Science
Sequencing of 50 human exomes reveals adaptation to high altitude.
Science
The alcohol flushing response: an unrecognized risk factor for esophageal cancer from alcohol consumption.
PLoS Medicine
Perceived social isolation and cognition.
Trends in Cognitive Sciences
The energetic significance of cooking.
Journal of Human Evolution
Identification and importance of brown adipose tissue in adult humans.
New England Journal of Medicine
New flutes document the earliest musical tradition in southwestern Germany.
Nature
Europe's Lost World: The Rediscovery of Doggerland
Council for British Archaeology
Mothers and Others: The Evolutionary Origins of Mutual Understanding
Belknap Press
Guidelines for the nomenclature of the human heat shock proteins.
Cell Stress and Chaperones
The End of Overeating: Taking Control of the Insatiable American Appetite
Rodale
Physical activity, diet, and risk of Alzheimer disease.
JAMA
Revisiting 'how many steps are enough?'
Medicine and Science in Sports and Exercise
Cold-activated brown adipose tissue in healthy men.
New England Journal of Medicine
Functional brown adipose tissue in healthy adults.
New England Journal of Medicine
Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004.
Archives of Ophthalmology
Helminths and the IBD hygiene hypothesis.
Inflammatory Bowel Diseases
Ardipithecus ramidus and the paleobiology of early hominids.
Science
Consumer antibacterial soaps: effective or just risky?
Clinical Infectious Diseases
The brain's default network: anatomy, function, and relevance to disease.
Annals of the New York Academy of Sciences
Hormesis: why it is important to toxicology and toxicologists.
Environmental Toxicology and Chemistry
Exercise and circulating cortisol levels: the intensity threshold effect.
Journal of Endocrinological Investigation
Influence of a 'warm touch' support enhancement intervention among married couples on ambulatory blood pressure, oxytocin, alpha amylase, and cortisol.
Psychosomatic Medicine
Helminth infections: the great neglected tropical diseases.
Journal of Clinical Investigation
Amount of time spent in sedentary behaviors in the United States, 2003-2004.
American Journal of Epidemiology
The epidemiology of adult obstructive sleep apnea.
Proceedings of the American Thoracic Society
Outdoor activity reduces the prevalence of myopia in children.
Ophthalmology
Sex differences in exercise metabolism and the role of 17-beta estradiol.
Medicine and Science in Sports and Exercise
Two routes to functional adaptation: Tibetan and Andean high-altitude natives.
PNAS
Absence of the lactase-persistence-associated allele in early Neolithic Europeans.
PNAS
Longevity among hunter-gatherers: a cross-cultural examination.
Population and Development Review
Vitamin D deficiency.
New England Journal of Medicine
Physiology and neurobiology of stress and adaptation: central role of the brain.
Physiological Reviews
Diet and the evolution of human amylase gene copy number variation.
Nature Genetics
Obesity and reproductive disorders in women.
Human Reproduction Update
Rough-and-tumble play and the development of the social brain.
Current Directions in Psychological Science
The evolution of foresight: what is mental time travel, and is it unique to humans?
Behavioral and Brain Sciences
A population-level decline in serum testosterone levels in American men.
Journal of Clinical Endocrinology and Metabolism
Origins of major human infectious diseases.
Nature
Why women live longer than men: sex differences in longevity.
Gender Medicine
Use of cognitive behavior therapy for functional hypothalamic amenorrhea.
Annals of the New York Academy of Sciences
Persistence hunting by modern hunter-gatherers.
Current Anthropology
The human gluteus maximus and its role in running.
Journal of Experimental Biology
The Storegga Slide tsunami: comparing field observations with numerical simulations.
Marine and Petroleum Geology
On the interactions of the hypothalamic-pituitary-adrenal (HPA) axis and sleep: normal HPA axis activity and circadian rhythm, exemplary sleep disorders.
Journal of Clinical Endocrinology and Metabolism
Origins and evolution of the Western diet: health implications for the 21st century.
American Journal of Clinical Nutrition
Controlled endurance exercise training and VO2max changes in older adults: a meta-analysis.
Preventive Cardiology
Innovation and technological knowledge in the Upper Paleolithic of Northern Eurasia.
Evolutionary Anthropology
Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder
Algonquin Books
Clues to the functions of mammalian sleep.
Nature
Endurance running and the evolution of Homo.
Nature
Changes in USDA food composition data for 43 garden crops, 1950 to 1999.
Journal of the American College of Nutrition
African climate change and faunal evolution during the Pliocene-Pleistocene.
Earth and Planetary Science Letters
The evolution of human skin and skin color.
Annual Review of Anthropology
A potential natural treatment for attention-deficit/hyperactivity disorder: evidence from a national study.
American Journal of Public Health
Fitness benefits of prolonged post-reproductive lifespan in women.
Nature
Effects of food processing on masticatory strain and craniofacial growth in a retrognathic face.
Journal of Human Evolution
Helminth parasites: masters of regulation.
Immunological Reviews
Does rejection hurt? An fMRI study of social exclusion.
Science
Bone's mechanostat: a 2003 update.
The Anatomical Record Part A
Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress.
Biological Psychiatry
Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide.
Science
The influence of painful sunburns and lifetime sun exposure on the risk of actinic keratoses, seborrheic warts, melanocytic nevi, atypical nevi, and skin cancer.
Journal of Investigative Dermatology
Comparison of straining during defecation in three positions: results and implications for human health.
Digestive Diseases and Sciences
The effect of infections on susceptibility to autoimmune and allergic diseases.
New England Journal of Medicine
Phototransduction by retinal ganglion cells that set the circadian clock.
Science
A new hominid from the Upper Miocene of Chad, Central Africa.
Nature
From Hand to Mouth: The Origins of Language
Princeton University Press
Identification of a variant associated with adult-type hypolactasia.
Nature Genetics
Heat shock proteins: modifying factors in physiological stress responses and acquired thermotolerance.
Journal of Applied Physiology
Diagnosis of osteoporosis and assessment of fracture risk.
The Lancet
Coordination of circadian timing in mammals.
Nature
Do stress reactions cause abdominal obesity and comorbidities?
Obesity Reviews
The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants.
Journal of Exposure Science and Environmental Epidemiology
Fruits, foliage and the evolution of primate colour vision.
Philosophical Transactions of the Royal Society B
Rotating shift work and risk of breast cancer in women participating in the Nurses' Health Study.
Journal of the National Cancer Institute
The evolution of human skin coloration.
Journal of Human Evolution
Folic acid: nutritional biochemistry, molecular biology, and role in disease processes.
Molecular Genetics and Metabolism
Navigation-related structural change in the hippocampi of taxi drivers.
PNAS
Effects of long-term microgravity exposure on cancellous and cortical weight-bearing bones of cosmonauts.
The Lancet
Evidence for the unique function of docosahexaenoic acid during the evolution of the modern hominid brain.
Lipids
Cardiovascular risk factors in a Melanesian population apparently free from stroke and ischaemic heart disease: the Kitava study.
Journal of Internal Medicine
The protective effects of estrogen on the cardiovascular system.
New England Journal of Medicine
What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience?
Brain Research Reviews
The Natufian culture in the Levant, threshold to the origins of agriculture.
Evolutionary Anthropology
The social brain hypothesis.
Evolutionary Anthropology
Grandmothering, menopause, and the evolution of human life histories.
PNAS
A neural substrate of prediction and reward.
Science
War Before Civilization: The Myth of the Peaceful Savage
Oxford University Press
The expensive-tissue hypothesis: the brain and the digestive system in human and primate evolution.
Current Anthropology
Biological changes in human populations with agriculture.
Annual Review of Anthropology
Abrupt increase in Greenland snow accumulation at the end of the Younger Dryas event.
Nature
Coevolution of neocortical size, group size and language in humans.
Behavioral and Brain Sciences
The evolution of nasal turbinates and mammalian endothermy.
Paleobiology
The evolution of sweat glands.
International Journal of Biometeorology
The thermoregulatory advantages of hominid bipedalism in open equatorial environments: the contribution of increased convective heat loss and cutaneous evaporative cooling.
Journal of Human Evolution
The worst mistake in the history of the human race.
Discover Magazine
Paleolithic nutrition: a consideration of its nature and current implications.
New England Journal of Medicine
Paleopathology at the Origins of Agriculture
Academic Press
An epidemiologic transition in dental occlusion in world populations.
American Journal of Orthodontics
Reproductive hormone increases in response to acute exercise in men.
Medicine and Science in Sports and Exercise
Aging, natural death, and the compression of morbidity.
New England Journal of Medicine
Concealment of ovulation, parental care, and human social evolution.
Evolutionary Biology and Human Social Behavior, Duxbury Press
Prospect theory: an analysis of decision under risk.
Econometrica
The !Kung San: Men, Women, and Work in a Foraging Society
Cambridge University Press
Does the chimpanzee have a theory of mind?
Behavioral and Brain Sciences
Arboreal adaptations and the origin of the order Primates.
The Functional and Evolutionary Biology of Primates, Aldine-Atherton
Episodic and semantic memory.
Organization of Memory, Academic Press
The Vertebrate Eye and Its Adaptive Radiation
Cranbrook Institute of Science
Read the book that cites them all
249+ peer-reviewed references woven into 34 chapters about the mismatch between your ancient DNA and modern life. This is the science made personal.
Get Spiral Staircase on Amazon