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1962;29;121-128 PediatricsT. Berry Brazelton
A CHILD-ORIENTED APPROACH TO TOILET TRAINING
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Online ISSN: 1098-4275. Copyright 1962 by the American Academy
of Pediatrics. All rights reserved. Print ISSN: 0031-4005. American
Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove
Village, Illinois, 60007.has been published continuously since
1948. PEDIATRICS is owned, published, and trademarked by the
PEDIATRICS is the official journal of the American Academy of
Pediatrics. A monthly publication, it
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A CHILD-ORIENTEDAPPROACH TO TOILETTRAININGT. Berry Brazelton,
M.D.
Department of Pediatrics, Harvard Medical School, and the
Massachusetts General Hospitaland the Children's Medical Center
P EDIATRICIANShave a unique opportunityto prevent problems for
the child in the
area of bowel and bladder control. Sincethe advent of
streamlined diaper care hasliberated mothers in our culture from
thereal need to traintheir children early,this step may be viewed
more honestly asa major developmental task for the child.Proper
timing of this may enable him toachieve mastery for himself. The
ultimatevalue of such self-achievement can beeasily weighed against
the adverse effectsof inopportune training by an adult society. The
pediatric and psychiatric literahire reports complications
resulting fromadverse toilet training.1'2 This paper willpresent
the results of a program for training in which utilizing the
child's developmental capacities and interest was the primary
goal.
Parents and pediatricians are aware thatthe child's autonomous
achievement in anydevelopmental area frees him to progressto more
advanced areas. Faulty masterymay leave him with a deficit that
results inregression under stress. The relationshipof coercive
toilet training to chronic constipation has been pointed out.7
Garrardand 411 presented six cases offunctional megacolon with
psychogenicetiology, in which the environmental pressure expressed
in training practices were aprimary factor. Glicklich5 summarized
psychogenic factors in enuresis. Encopresis2'4'9'1' and urinary
incontinenc&3'14 canbe traced to adverse or punitive
trainingpractices. Such pathologic symptoms usually reflect a
fundamental psychologic disturbance in the child's adjustment. But
inhealthful situations, parents can be encouraged to produce a
positive reaction in thechild to his control of bowel and
bladder.
This paper will outline a child-orientedapproach to
toilettraining at around 2years, geared to each child's
developmentalcapacities. The results from 1,170 childrenin 10 years
of pediatric practice, for whomthis program was suggested, are
summarized.
THEORY
The method suggested was constructedon several assumptions based
on observations of physical and emotional maturationin
children.
Voluntary Control of Sphincters
Local conditioning of reflex sphinctercontrol can be effectively
elicited as earlyas 9 months and has been the basis for anearly
introduction of@ Voluntaryco-operation may be elicited as early
as12 to 15 months, and this period has been
79, 12, 15 as optimal for training.
However, myelinization of pyramidal tractsto these areas is not
completed until thetwelfth to eighteenth month.16 Associatedwith
the transition from reflex compliance toa more voluntary type of
developmental accomplishment, there is usually a perceptible
time lag. In this period there is a kind ofsubtle inner
resistance to outside pressureon the part of the child. This may be
seenin many other developmental areas, suchas reflex standing at 5
months to voluntarystanding at 10 months, and vocalizations inthe
first year to verbal expressions in thelatter half of the second
year. This periodis probably an important period of incorporation
and of gathering inner forces forthe child. In a complex area such
as toilettraining, it would be even more likely thatany training
based on early reflex compliance would go through a subsequent
period
ADDRESS: (Office) 51 Brattle Steet, Cambridge 38,
Massachusetts.
121
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122 TOILET TRAINING
of bag and breakdown before voluntarycompliance on the part of
the child couldensue.
Postponed breakdown in a controlachieved before 12 to 18 months
is muchmore frequent than that seen when control is accomplished
after 18 months.7' 20That this breakdown in control can be
circumvented by pressure from the environment is easy to see in
some European cubtures, where the incidence of postponedbreakdown
is much lower than in our ownless rigid 24,19However the severity
and intractability of the symptoms pro
duced in the deviant cases in these countries is good evidence
for the strength ofthe child's inner resistances, which bringabout
such breakdowns. The incidence offailure in England is reported as
varyingfrom 10 to 15%.2,13
Motor Adjuncts to Training
Other aspects of motor developmentparticipate in the ease with
which a child
achieves training. He must be abbe to sitand to walk in order to
maintain some degree of autonomy about leaving the pottychair, and
some understanding of verbalcommunication is a help.
The developmental energy invested inlearning to walk on his own
is freed after15 to 18 months and can be transferred tothe more
complex mastery of sphincter control and toilet training.
Impulse Control
There must be a psychologic readinessassociated with a desire to
control the finpulses to defecate and urinate. These finpulses are
associated with a kind of primitive pleasure and an immediacy. The
realization of and wish to control them is dependent on influences
from the environment. Chief among them are 1) securityand
gratification in the relationship withparent figures, resulting in
a desire to pleasethem; 2) the wish to identify with and imitate
his parents and other important figures in his environment; and 3)
the wishto develop autonomy and mastery of himself and his
primitive impulses.8@17,21,22
These psychobogic processes come to the forein the latter half
of the second year and appear to reach a peak of readiness in
mostchildren beginning at 18 months and increasing to 30
months.
Other Psychologic Processes
At about 2 years of age there is a periodin most children in our
culture that ischaracterized by organizing and settingthings in
their proper places. Even a trendtoward personal cleanliness may
develop.These trends are useful in understanding areadiness for
toilet training.
There is an ebb and flow of negativism inthis period of
development, and it must beaccounted for in urging new
accomplishments. As it is difficult for a parent orphysician to
evaluate the degree of negativism that is active at any particular
time,it is necessary to pace any such programslowly and with enough
elasticity to allowfor these subtle variations.
PARENTAL INVOLVEMENT
Sears et al.18 pointed to many of the complexities of parental
feelings about toilettraining in our culture. The child's abilityto
learn by imitation is complicated bytaboos centered around modesty
and thesexual feelings of the parents. For parentswho wanted to
train their children earlyin order to avoid such complex areas as1)
sexuality, 2) cultural pressure from oldergenerations, or 3) strong
compulsive feelings about cleanliness, pressure to delaytraining
increased the parents' anxieties.They found, however, that many of
theirgroup of young parents were intransitbetween old and new
theories (p. 109)and were in conflict about the age at
whichtraining might best be instituted. Thenewtheories12'20
suggested waiting for thechild's readiness. In the group who
wereable to postpone training, less time wasrequired to complete
it. But Sears et al.wondered whether parents who werepushed to
delay against their wishes mightnot increase the tension around
this areafor the child.
We have found that a child-oriented
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ARTICLES 123
approach in the group of parents in ourstudy could divert some
of their own anxiety, provided there was the guidingearof a third
person, such as the pediatrician.
The conviction that this was betterfor thechild undoubtedly
acted as a counterbalance to the older cultural influences, aswell
as to their own sexuabized taboos inthis area. Since the child's
autonomousachievement was constantly the focus,there was the
implication that there wasless parental responsibility for failure
inthe child's lack of accomplishment. Tension could be reduced by
airing parentalconflicts and by assurance that the childwould
achieve control in his own time.
PROCEDURE
Advice was geared to each individualsituation. At the 9-month
visit the questionof future toilet training was raised with
theparents. Because the grandparents' generation usually began to
press them at thistime, it has proven to be an optimal periodfor
the discussion of future plans in thisarea. With a program planned,
the parentswere better able to withstand outside pressure to
institute an early attempt at training the child.
Before suggestions were introduced, theparents' own feelings in
this highly-chargedarea were explored. A repeated opportunityfor
them to express their own resistancesand anxieties about toilet
training was finportant in preventing their expressing
themunconsciously to the child. The importanceof a relaxed,
unpressured approach to training for the child was constantly
stressed.
This method was presented as an adjunctto helping the child meet
society's demandsin this area. Because there is little innatein the
child that leads him to want to beclean and dry, it must be
understood as akind of compliance to external pressure.The act of
giving up the instinctual methodof wetting and soiling to comply is
evidenceof 1) healthy maturation in the child,coupled with 2) a
wish to identify with anadult society.17 Hence the optimal
timingfor such pressure must be geared to eachchild's physical and
psychological readiness
to cooperate. With his autonomous achievement of this major
task, the reward for himis equivalent to that seen with his
masteryof standing and walking and becomes avaluable step in his
developmental progress. The danger of residual symptoms isthen at a
minimum.
The importance of timing the introduction of this method to the
child's readiness,and of allowing him freedom to mastereach step at
his own pace, was reiteratedat each subsequent visit. Problems
withthe child and resistances or questions fromthe parent were
discussed at each opportunity. Since this was not necessarily
anattempt to prejudice parents for this particular approach to
toilet training, everyeffort was made to help them with theirown
method. However, when problemsarose, the child's interests were
placed foremost in the discussion.
Method of Training
At some time after the child is 18 monthsof age, a pottychairon
the floor is introduced as the child's ownchair. Duringthe period
of getting familiar with it, association between it and the
parents' toiletseat is made verbally. At some routinetime, the
mother takes him each day to siton his chair in all his clothes.
Otherwise,the unfamiliar feeling of a cold seat caninterfere with
any further co-operation. At
this time, she sits with him, reads to him orgives him a cookie.
Since he is sitting on achair on the floor, he is free to leave
atwill. There should never be any coercionor pressure to
remain.
After a week or more of his co-operationin this part of the
venture, he can be takenfor another period with hia diapers off,
tosit on the chair as the routine. Still no attempt to catchhis
stool or urine is made.Catchinghis stool at this point canfrighten
him and result in his holdingback for a longer period thereafter.
Thisgradual introduction of the routine is madeto avoid setting up
fears of strangeness andof loss of partof himself.
When his interest in these steps isachieved, he can be taken to
his pot a sec
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124 TOILET TRAINING
ond time during the day. This can be afterhis diapers are
soiled, to change him onthe seat, dropping his dirty diaper
underhim into the pot, and pointing out to himthat this is the
eventual function of hischair.
When some understanding and wish tocomply coincide, there will
be verbal oractive compliance on the first routine trip.Then he can
be taken several times a dayto catchhis urine or stool, provided
heremains willing.
As interest in performance grows, thenext major step becomes
feasible. All diapers and pants are removed for shortperiods, the
toilet chair is placed in hisroom or play area, and his ability to
perform by himself is pointed out. He is encouraged to go to his
own pot when hewishes and by himself. He may be
remindedperiodically that this is indicated. When heis ready to
perform alone, this becomes anexciting accomplishment, and many
children take over the function entirely at thispoint. Training
pants can be introduced,the child instructed as to their removal,
andthey become an adjunct to his autonomouscontrol. The excitement
which accompanies mastering these steps by himself iswell worth the
postponing until he canaccept them.
Teaching a boy to stand for urination isan added incentive. It
becomes a part ofidentifying with his father, with other boys,and
is often an outlet for a normal amountof exhibitionism. It is most
easily learnedby watching and imitating other male figures. It is
better introduced after boweltraining is complete. Otherwise, the
excitement of standing for all functions supersedes.
Nap and night training are left untilwell after the child shows
an interest instaying clean and dry during the day. Thismay be 1 to
2 years later, but it often be.comes coincident with daytime
achievement. When the child evidences an interestin night training,
the parent can offer tohelp him by rousing him in the early evening
and offering him a chance to go to thetoilet. A pot painted with
luminous paint
by his bedside is often a useful gimmick.He is reminded that
this is there for earlymorning use also. Some children who areeager
and ready to remain dry at nighthave needed further help from the
parentsto awaken in the early morning for an interval. When this is
not forthcoming, theyfail in their efforts at night, lose
interestand feel guilty in their failure. Then, enuresis and
givingupmay follow.
These steps are stressed as the child'sachievement, and when
there is a breakdown the parent is urged to stop the process and to
reassure the child. He needs thereassurance that he is not badin
hisfailure to achieve, and that someday hewill co-operate when he
is ready.
RESULTS
The results are compiled from unselected
records of 1,170 patients over 10 years ofpediatric practice (
1951-1961) in Cam
bridge, Massachusetts. Upper-middle-classwell-educated parents
comprised the majorportion of patients in this group. They
livedunder economic pressure, and mothers werewashing their own
diapers, so there wassome practical pressure to achieve
training.But their desire to give their children athoughtful
environment freed them in mostcases to want to follow the
suggestedmethod.
The sample consisted of 672 (57.4%) maleand 498 (42.6%) female
children, of whom660 (56.4%) were first children and
450(43.6%)weresecondor later.It wasfoundthat the position in the
family was a factorin determining the kind of environmentalpressure
which existed. With the first childthere was usually more anxiety
shown bythe parents about waiting to train the child,more
ambivalence about this delayedmethod, but surprise and relief when
training was accomplished. The later childrenwere given more
freedom to train themselves at their own speed. However
somepressure on these later children to conformcame from the older
siblings. Imitation ofthe older children often facilitated
trainingin the younger ones.
The daytime training of first children
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ARTICLES
Fic. 1. Ages at which toilet training was instituted.
125
NUMBEROF CHILDREN
650-600-550-
500-450-400-350-300-250-200-
I 50-$00-50-
AGE MONTHS
640
5
@k i'@ te 2$ 2'4 27 30 33 3C
was effected 1 to 2 months later than intheir younger siblings.
Night training wasdelayed 1 to 7 months longer in first children
than in subsequent siblings. Figure 1summarizes the ages at which
training wasstarted. The preponderance of patients whostarted
around 24 months reflects these parents' willingness to accept this
advice, and,with second children, their own choiceabout such
timing. Figure 2 summarizesthe ages at which parents reported
the
NUMBEROF CHILDREN450425-
400-375.
350
325.
300
275.
250225.
200
75
150-
$25.
100.
75.
50.
25
-.----t------I - L
AGE-MQNTH$ $5 8 21 24
child's initial success, which was maintained. One hundred
forty-four (12.3%)achieved bowel training first, 96 (8.2%) were
trained for urination first, and 930 (79.5%)were reported as
training themselves simultaneously for bowel and bladder control.Of
the 930, some 839 (90.3%) were between24 and 30 months of age. The
average ageof the total group who accomplished initialsuccess was
27.7 months.
Initial success reflects an understanding
438
324
252
I
I I I I27 30 33 36
Fic. 2. Areaof firstachievementin training.
245
125
47 48rn
60 60fin
rTlllBOWELLiii TRAINING
a URINETRAINING
D URINE AND BOWELTRAIN INSSIMULTANEOUS
66
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126 TOILET TRAINING
384
310
t50
NUMBEROF CHILDREN
400375
35o-@32513 OO-j275@[email protected].
10075
5025
Fic. 3. Ages at completion of daytime training.
r@1 ISII 6I I I I I I I I I I
AGEMONTHS It IS IS SI 24 27 30 33 36 39 42 45 45
of the use of the toilet rather than amastery of the process.
Figure 3 summarizes the ages of completion of daytimetraining. Nine
hundred forty-four (80.7%)accomplished this between the ages of
2and 2%years. The average was 28.5 months.No significant difference
was noted between males and females. Day trainingmeans an absence
of accidents under theusual stresses. When a breakover occursunder
stress, it is of temporary durationonly (less than 1 month).
Night training implies 1) that subsequentfailure was reduced to
less than once aweek and 2) that enuresis returned under
NUMBEROFCHILDREN
unusual stress only, e.g., a new baby, moving, absence of a
parent, etc., and resolveditself again in a short time (less than
2months). Figure 4 summarizes the ages ofnight training. Sixteen
(1.4%) children areincluded who had residual problems ofenuresis,
encopresis and constipation beyond the age of 5 years. In the total
group940 (80.3%)were completely trained by theage of 3 years. The
average age of all training was 33.3 months. Females were
completely trained 2.46 months before males.
There were 150 children in this groupwhose training was not
completed until3%years. Forty-eight, or approximately one
375.350-525-300275-250225200-
175
1S0 32
125.@ [I
100-.75-50. .r1LL@25- 10ME-MONTHS 21 24 27 30
360
ISIi,,
I I I I I I I
33 36 39 42 45 4S SI 54 57 60 @5yrs.
Fic. 4. Agesat completionof night training.
I'S
ISO
fin
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ARTICLES 127
third of these, were started to be trainedbefore 18 months. One
hundred and eight(9.2%) were untrained by 4 years. Of these70 or
two-thirds had started training be
fore 18 months. Of the 16 problem children only two had started
early, and thetime of training them seemed to have littleinfluence
in creating their more severe dif
ficubties.Of these 16 children, 12 were enuretic
after 5 years of age, 4 soiled in stress situations, and 8 had
chronic constipation.There were environmental problems in allof
these cases, and it was obvious that ineach of these children the
above symptomsreflected deeper disturbances of a psychogenic
nature. But of the other 1,154 in thegroup, there were often
similar environmental stresses present, and it is encouraging that
these did not produce problemsin the training area. This suggests
that byallowing the child more freedom to develophis controls at
his own speed, problems insuch an area may be prevented,
providedparental anxiety in this area can be avertedalso. It is not
possible in this paper topresent the details of techniques
availableto pediatricians which can facilitate thehandling of
incipient problems, but theseresults bead one to believe that such
achild-oriented approach does divert environment tension from this
area and mayreduce the incidence of subsequent difficulties.
SUMMARY
Results of toilet training obtained fromthe records of 1,170
children in pediatricpractice over a 10-year period are summarized.
The suggested method stressedthe child's interest and compliance in
developing autonomous control. This was instituted at about 2 years
of age and depended on his physiologic and
psychobogicreadiness.
Initial success was achieved simubtaneously in both bowel and
urinary control in79.5% of the cases, 12.3% in bowel controlalone,
and 8.2% in urinary control. This firstaccomplishment was reached
at an average
age of 27.7 months. Daytime training wascompleted between 2 and
2% years of agein 80.7% of this group. The average age forday
training was 28.5 months; males andfemales showed no significant
difference;first children were 1.2 months slower thantheir
siblings. Night training was accomplished by 3 years in 80.3% of
cases. Theaverage age for completion of all trainingwas 33.3
months. Males took 2.46 monthslonger for complete training. First
childrenwere delayed 1.7 months in complete training in relation to
their siblings.
Of the children who had chronic diffi
culties in this area, 76 (6.5%)were untrainedat 4 years, and 16
(1.4%) were failures bythe age of 5 years. The value of such
achild-oriented program in preventing residual symptoms is
stressed.
REFERENCES
1. Bell, A. I., and Levine, M. I. : The psychologicaspects of
pediatric practice : I. Causes andtreatment of chronic
constipation. PzmATRICS, 14:259, 1954.
2. Bodian, M., Stephens, F. D., and Ward, B. C.H. :
Hirschsprung's disease and idiopathicmegacolon. Lancet, 1 :6,
1949.
3. Davidson,M.: Constipationand fecal incontinence. Pediat.
Clin. N. Amer., 5:749, 1958.
4. Garrard, S. D., and Richmond, J. B. : Psychogenic megacolon
manifested by fecal soiling.Pznwrmcs, 10:474, 1954.
5. Glicklich, L. B.: An historical account ofenuresis.
PEDIATRICS, 8 :859, 1951.
6. Greenacre,P.: Urinationand weeping.Amer.J. Orthopsychiat.,
15:1, 1945.
7. Huschka, M. : Child's response to coercivebowel training.
Psychosom. Med., 4:301,1942.
8. Isaacs, S.: On Bringing Up of Children. NewYork, Brunner,
1952.
9. Prugh, D.: Childhood experience and colonicdisorders. Ann. N.
Y. Acad. Sd., 58:355,1954.
10. Reichert, J. L. : Constipation in infants andyoung children.
Pediat. Clin. N. Amer., 2:527, 1955.
11. Richmond, J. B., Eddy, E. J., and Garrard,S. D. : Syndrome
of fecal soiling and megacolon. Amer. J. Orthopsychiat., 24:391,
1954.
12. Spock, B., and Huschka, M.: The PsychologicAspects of
Pediatric Practise, Vol. 13. (Practitioner's Library of Medicine
and Surgery).New York, Appleton-Century, 1938, p. 775.
by Cynthia Ferrell on April 15, 2011
www.pediatrics.orgDownloaded from
http://www.pediatrics.org
-
128 TOILET TRAINING
13.Bromfeld,J. M., and Douglas,J.W.: Bedwetting prevalence among
children aged 4-7 years. Lancet, 270:850, 1956.
14. Cole, N. J.: Assessment current parental practises. Amer. J.
Orthopsychiat., 27:815, 1957.
15. Gesell, A., and Thompson, H.: Psychology ofEarly Growth. New
York, Macmillan, 1938,p.142 if.
16.Ford,F.R.:DiseasesoftheNervousSysteminInfancy, Childhood and
Adolescence. Springfield, Ill., Thomas, 1952.
17. Escalona, S.: Emotional Development in theFirstYearof
Life.New York,Macy, 1952.
18. Sears, R. R., Macoby, E. M., and Levin, H.:Patterns of Child
Rearing, Evanston, Ill.,Row, Peterson & Co., 1957.
19. Conrad, S. J.: Study of preschool children.Amer. J.
Orthopsychiat., 18:340, 1948.
20. Hill, L. F.: Expected behavior in children.Minnesota Med.,
41:114, 1958.
21. Leitch, M., and Escalona, S.: Reactions of infants to
stress, in Psychoanalytical Study ofChild, Vols. 3 & 4. New
York, InternationalUniversitiesPress,1949.p.121 if.
22. Senn, M. J. E.: The Healthy Personality, Vol.2. Macy,
1950.
A P@nc@i.@ OUTLINEFORPREPARINGM@ICAL TALKS AND P@i@iis, Robert
M. Zollin
ger, M.D., William G. Pace, III, M.D.,
and George J. Kienzle, B.A. New York,Macmillan, 1961, 57 pp.,
$1.95.
This booklet of 64 pages is as simple, practical, and prosaic as
the reminders inside itsfront and back cover for the medical man
when(A) returning from meetings (Answeraccumulated mail. Report
interesting and newinformation to staff. Outline plans for
newprojects.) and when (B) preparing for visitors
(Plancoffee breaks. Special honorarium mustbe arranged well in
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reading for most.The eight pages devoted to medical writing
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Perhaps most welcome of all is the sectionon projection screens,
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roomsize, wattage of bulb, and focal length projector.
The Director of the Department of VisualEducation of the
Children's Hospital MedicalCenter tells us: Thisbooklet is well
done,authentic. I approve heartily. Coming fromF. B. Harding, this
approval is impressive.
C.A.S.
BOOK REVIEW
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1962;29;121-128 PediatricsT. Berry Brazelton
A CHILD-ORIENTED APPROACH TO TOILET TRAINING
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