The science of toilet training:
What research tells us about timing
© 2007-2010 Gwen Dewar, all rights reserved
When is the best time to begin toilet training? Infancy? 18 months? 24 months? Or even later?
There is surprisingly little research addressing this question. As I note elsewhere,
each age is associated with its own costs and benefits.
But it's fair to make a two general points.
1. The widespread belief that early potty training causes psychological or behavioral problems is not supported by the evidence. As I note below, this idea seems to have arisen because people conflated early training with bad training.
2. Kids who are trained late--i.e., after 32 months--might be at greater risk for developing bladder problems.
For the details, read on.
Part 1: A recent history of toilet training attitudes
Many parents--particularly Western parents--worry that early toilet
training is harmful to children. This idea has been promoted by
pediatricians and child-care professionals. As I will argue below, the
scientific evidence doesn’t back it up. But where did the idea come from
in the first place?
Early potty training got a bad reputation because it was once associated with bad training methods.
the 1920s and 1930s, parents were urged to impose a rigid toilet
training regimen on children before they could walk. Techniques were
coercive, even abusive.
One government manual instructed parents
to enforce “absolute regularity” of bowel movements by inserting a soap
stick in the infant’s rectum at precise times of the day (United States
Department of Labor 1935).
Other prevalent tactics included
scolding and physical punishments for accidents (Hushka 1942; Stendler
1950; Luxem and Christophersen 1994.)
After World War II, the medical establishment began to reject early potty training.
Freudians claimed that early, rigid training caused emotional problems and neuroses later in life.
like Benjamin Spock and T. Berry Brazelton, argued that pushing
children may cause a variety of troubles, including stool withholding,
stool toileting refusal, regression, and
(Leiberman 1972; Brazelton 1962; Brazelton and Sparrow 2004).
development researchers argued that training should not begin until
kids could actively cooperate with the process (Brazelton et al 1999).
Strict timetables for training were abandoned. Instead, parents were
encouraged to let their children’s spontaneous curiosity set the pace.
These changes probably saved many children from harsh training methods.
But reformers seem to have confused methods with timing.
one historical study I’ve read, the author clearly stated that that any
training before 10 months is, by definition, coercive (Hushka 1942).
important point is that “when to train” and “how to train” are
different questions. Bad training methods can cause problems.
But does early timing cause problems? Based on modern studies, the answer appears to be “no.”
Part 2: Modern scientific studies
Early training doesn't cause problems
The few scientific studies of
infant toilet training
have reported no negative side effects (Ball 1971; Cederblad 1970;
Smeets et al 1985). These studies focused only on basic skills and did
not track children over the long-term. But the cross-cultural evidence
suggests that long-term toilet training problems are rare (Ainsworth
1967; deVries and deVries 1977).
The evidence for toddler training tells a similar tale. Earlier training is not associated with behavioral problems.
recent American study tracked over 400 children to learn what, if any,
effects timing has on toilet training success (Blum et al 2003).
were enrolled in the study at 17-19 months. Their parents were
interviewed every 2-3 months until they completed daytime potty
training. Researchers compared children who began “intensive”
training—-defined as being asked to use a potty chair or toilet more
than three times a day—-before 27 months with those who began intensive
training after 27 months.
The earlier starters were no more likely
than later starters to experience constipation, stool toileting
refusal, stool withholding, or hiding from parents (Blum et al 2003).
only negative finding was that children trained earlier tended to take
longer to complete training. Kids who starting training between 18-24
months took, on average, 13-14 months. Kids who trained after 27 months
took 10 months or less (Blum et al 2003).
The authors infer from
this result that there is “little benefit” in beginning potty training
between 18 and 27 months (Blum 2003).
However, the study directed
parents to use a gradual, child-oriented approach to potty training. As
a result, the younger participants might have been less prepared for
training, which would have slowed their progress. If parents had been
instructed to actively prepare their children for training, the results
might have differed.
Moreover, the study by Bloom and colleagues
didn’t address training before 18 months. When infant training is the
goal, children may finish within 5-9 months (Smeets et al 1985; Boucke
Other research suggests that later training is associated with problems.
Delayed training might put kids at higher risk for developing bladder problems
A recent case control study interviewed the parents of older kids
(aged 4 – 12) who had been diagnosed with daytime incontinence (Barone
et al 2009). These kids still had trouble suppressing the urge to
urinate. Was there anything in their toilet training history that stood
When the kids were compared with a control group,
researchers found that the incontinent kids were more likely to have
begun toileting training after 32 months.
Previous studies have also reported links between late training and bladder trouble.
Belgian researchers interviewed the parents of kids in grade school and middle school (Bakker et al 2002a, Bakker et al 2002b).
found that school-age kids with bladder problems--like daytime
accidents, bedwetting, and recurrent urinary tract infections--were more
likely to have started toilet training at a later age.
results should be interpreted with caution. The case control study
doesn’t tell us much about causation. And the Belgian study depended on
parents’ recall many years after the fact.
Maybe some toddlers
possess traits that make their parents delay training--and perhaps these
same traits lead to more bladder problems later in life.
too, parents with symptom-free children are more likely to minimize the
effort of toilet training and to forget how early the process began.
But it makes sense that earlier training could reduce the incidence of urinary tract infections.
training helps children learn to completely empty their bladders—-an
ability that reduces the risk of infection (Janson et al 2000; Sillen
and Hanson 2000).
As a result, some researchers recommend that
children with dysfunctional bladders should start training early
(Hellstrom and Sillen 2001).
As for Freud, it’s interesting to
note that Freud never singled out early training as the cause of
personality disorders. He was concerned about any approach to training
that might be regarded as extreme—too early, too late, too strict, too
“libidinous” (Fenichel 1945, p. 305).
In any case, I can find no
scientific studies that link the timing of toilet training with the
later development of emotional disorders. Freud identified certain
personality types that have been confirmed by modern scientific studies.
However, these personality types have NOT been linked to childhood
toilet training experiences (Fisher and Greenberg 1977; Masling 1999).
For more information, be sure to check out my article on
choosing the right potty training age,
as well as these
evidence-based potty training tips.
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Content of "The Science of toilet training: What research tells us about timing" last updated 4/10