Early Continence Is the Global Norm: The Digo of Kenya (deVries & deVries 1977, Pediatrics)
Day and night dryness by 5 to 6 months, achieved gently, in a culture that starts at birth.
Among the Digo of coastal Kenya, caregivers begin elimination training in the first weeks of life and report day and night dryness by five to six months, through warm, responsive conditioning rather than coercion.
This 1977 study in Pediatrics is the foundational anthropological source for the idea that diaper-free infant care is not a fringe trend but a human norm. Among the Digo of coastal Kenya, caregivers believe infants can learn soon after birth and begin elimination training in the first weeks of life. With what the authors call a nurturant conditioning approach, warm and responsive rather than coercive, day and night dryness is reported by five to six months.
The authors concluded that sociocultural factors matter more in toilet-training readiness than is usually assumed. In other words, the Western belief that a child cannot manage elimination until age three is a cultural assumption, not a developmental law.
It is a single observational study of one culture from 1977, so it shows what is possible and normal elsewhere, not that early training is universally optimal or causes any benefit. As the cross-cultural anchor, it does exactly one job well: it proves early, gentle continence is genuinely achievable.
First weeks
When training begins
5-6 mo
Reported day and night dryness
Nurturant
The method: responsive, not coercive
Why it matters
Much of the world has raised babies this way. Early dryness through gentle, responsive care is achievable, and our age-three expectation is a recent cultural habit.
This is one finding from the research library behind How to Birth a Mother. Everything here traces back to a study, a dataset, or a systematic review.