J. ment. Defic. Res. (1984) 28, 269^274

MATERNAL INFLUENCE ON THE TASKBEHAVIOUR OF YOUNG DOWN'S SYNDROME

CHILDRENPAUL BERRY and PATRICIA GUNN

Fred and Eleanor Schonell Educational Research Centre, University of Queensland,St Lucia, Queensland 4067, Australia

I N T R O D U C T I O N

Goodman (1979; 1981a, b) has described studies of young intellectually handicappedand non-handicapped children using the lock box. The lock box is an instrumentdesigned for the measurement of mental organization in children and comprises arectangular container with 10 doors, each of which has a different lock. Behind eachdoor is a different toy. The analysis of the child's behaviour during play with the lockbox falls into three main categories namely competence, organization and aimlessactions. Two methods of evaluating competence are employed, the first concerns thenumber of doors unlocked and the second the number of unsuccessful attempts tounlock the doors. In the present study, relocking behaviour has also been coded sincean earlier investigation (Berry, Gunn & Andrews, 1984) had found that the number ofdoors relocked was significantly associated with competent performance. Organiza-tion scales refer to the child's patterns and sequences of behaviour while playing withthe box. Organization A is based on the number of adjacent locks the child tries insequence. Organization B is concerned with the consistency ofthe child's actions oncea door is unlocked. Aimless actions are measured by the number of perseveringopen-close door actions plus off-task behaviours such as leaving the box. Goodman(1979) has reported that the mentally handicapped, compared with normal controlchildren, opened fewer locks, experienced more failures and left more locksunexplored. They were less organized and displayed more aimless actions. In anotherstudy. Berry, Gunn & Andrews (1984) used the lock box with 17 Down's syndromechildren (mean CA 37.4 months, SD 10.1) and 17 non-handicapped children (meanCA 37.4 months, SD 10.2). Their results replicated Goodman's research in that thenon-handicapped children displayed greater competence, more organization and lessperseverance. This study employed younger handicapped children than Goodmanand showed that the situation was appropriate for this age group; it was also suggestedthat it was a useful situation for assessment of Down's' syndrome children since it isessentially a non-verbal task and ability to score on the competence and organizationscales was significantly associated with mental age. Since many Down's syndromechildren display language delay, the lock box task is especially attractive forassessment of these children.

Received 25 November 1983

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270 P . BERRY and P . G U N N

One major difference, however, betweeen the study of Berry, Gunn & Andrews(1984) and those of Goodman (1979; 1981a, b) was that in the former study themother was allowed to talk to and encourage her child although she was not permittedto touch the lock box itself. This may have influenced the results of the children inthat maternal encouragement may affect not only the number of locks opened orclosed but also the pattern and sequence of the child's actions.

The present study was designed to investigate maternal influence on children inthe lock box situation. It was assumed, in particular, that the mothers' encouragementwould influence the children to stay 'on task' longer and thus maximize theircompetence and organization scores with the minimum of persevering behaviour.

METHOD

The subjects were 21 (8 girls) Down's syndrome children (mean CA 45.5 months, SD12.4; mean MA 24.8 months, SD 7.5) and 13 (3 girls) control non-handicappedchildren (mean CA 39.9 months, SD 11.6). All age data refer to the first session of thisstudy. Chromosome analyses for the Down's syndrome children showed trisomy 21for 19 children, a translocation for one boy and mosaicism for one girl. Mental ages forthe Down's syndrome children were calculated from a mental age data set on eachchild. The method used a maximum likelihood programme (Beale & Little, 1975) toestimate mental age at the time of each session in this study.

This programme provides an estimate of mental age for the specific dates of eachlock box session. The mental age is estimated as a linear function from the data set ofassessment results which were available for each child both before and after each lockbox session. The assessment instruments included the Bay ley scales of infantdevelopment, the Merrill-Palmer and the Stanford-Binet. The technique wasadjusted for bias and did not assume a multivariate normal population.

All the Down's syndrome children were home reared from predominantly middleclass families. None ofthe normal children were developmentally delayed and all hadcompleted items such as the Seguin form board from the Merrill-Palmer testappropriate for their CA.

All of the children had played with the lock box with their mothers about 6months previously for about 5 minutes. This session was regarded as an orientingexperience for mothers and children. It also minimized any differences between thefollowing sessions which might be caused by novelty or practice. In the present studyon the first session the mothers were instructed not to talk or interact with theirchildren while they played with the lock box and were given a questionnaire to fill out.The experimenter opened each door, showed the toy to the child and relocked thedoor. The child was then left in the room with his/her mother for 5 minutes. Thechild's behaviour was videotape recorded. If the children approached their mother,the mother was instructed to say 'I'm busy just now, go and play with the box'. On thesecond occasion, which took place about 3 months later, the mothers were instructed'talk to him/her and encourage him/her to try the locks and to stay at the task. Don'ttouch or open any locks or doors yourself. No instructions were given as to how the

TASK BEHAVIOUR IN DOWN'S SYNDROME 271

verbal interaction should proceed. Other procedures such as the experimenteropening the doors and showing the toys were as for the first session.

A N A L Y S I S OF DATA

The analysis of the data was based on some of the scales described by Goodman(19816). The categories were (a) competence A: the total number of doors successfullyopened, (b) competence B: the total number of locks unsuccessfully attempted, (c)attempts to lock: the total number of attempts to relock a door, (d) successful locking:the total successful attempts at relocking doors, (e) organization A: the sequence ofdoors explored, (f) organization B: the consistency in the pattern of behaviour e.g.open door, remove toy, close door, lock door, (g) aimless actions: the total number ofaimless activities including perseveration, leaving the box, and repeated returns to thesame lock.

R E S U L T S

The mean results and standard deviations for each group of children are given inTable 1. The Pearson product-moment correlation between mental age, chronologicalage and lock box measures is provided in Table 2. There are a number of significantassociations between the lock box measures and age for both sessions and for bothgroups. The score for aimless actions was unrelated to mental age in all cases. Arepeated-measures MANCOVA design which partialled out the effects due to MA wasthen used in a group by session design. Sphericity tests were non-significant for allcomparisons. The level of significance for each variable is shown in Table 3.

This analysis showed a significant relationship between mental age and all lockbox measures except aimless actions. There is also a significant group effect forcompetence A and B, for attempts at locking and successful locking, and for aimlessactions. The session effect was significant only for aimless actions.

There was one significant interaction effect, that for successful locking.

Table 1. Mean scores on lock box measures

ScaleCompetence ACompetence BAttempts to lockSuccessful lockingOrganization AOrganization BAimless actions

MeanDown's syndrome group

Session 1

2.8 (1.4)4.1 (1.4)2.1 (1.4)1.0 (1.1)1.3 (1.7)1.2 (2.6)4.7 (4.7)

Session 23.7 (1.4)4.2 (2.1)2.2 (1.6)1.3 (1.4)1.2 (1.8)2.7 (3.6)3.9 (3.7)

scoresComparison

Session 1

5.5 (1.6)1.8 (1.8)4.9 (1.5)3.7 (1.7)1.2 (1.7)3.1 (3.1)0.0

groupSession 2

7.1 (2.0)1.3 (1.8)6.5 (2.1)6.0 (2.1)3.2 (3.5)4.5 (4.1)0.0

Session 1: without mother encouragement.Session 2: with mother encouragement.Results are mean (SD).

272 P. BERRY and P. GUNN

Table 2. Correlation of chronological and mental ages with lock box scores

Scale

Competence ACompetence BAttempts to lockSuccessful lockingOrganization AOrganization BAimless actions

ComparisonSession I

0.56*-0.42

0.52*0.63**0.170.10

nc

Chronological agegroupSession i

0.50*-0.55*

0.52*0.50*0.420.14nc

Down's syndrome groupI Session i

0.320.060.56**0.43*0.000.42*

-0.12

' Session 2

0.44*-0.30

0.54**0.58**0.170.54**0.03

DownMental age's syndrome group

Session I Session 2

0.690.240.630.620.210.410.06

*** 0.55**-0.47*

*** 0 75****** 0.78***

0.40** 0.70***

-0.04

Session 1: without mother encouragement.Session 2: with mother encouragement.nc = not calculated due to zero incidence of behaviour.***P<0.001; **P<0.01; *P<0.05.

Table 3. Significance levels and F ratios for the MANCOVA comparing Down's syndrome andcontrol children (group) in conditions with and without mother encouragement in the lock boxsituation (in all cases d.f. = 1,31)

Scale

Competence ACompetence BAttempts to lockSuccessful lockingOrganization AOrganization BAimless actions

MA

F = 26.9***F = 6.26*F = 31.4***F = 26.8***F = 8.0**F = 8.2**

FFFF

F

GP

= 12.8**= 6.5*= 18.9***= 18.7***

= 12.5**

RFP GPxREP

F = 11.5*

F = 4.2*

***P<0.001; **P<0.01; *P<0.05.MA = mental age as a covariate; GP = Down's syndrome vs control children; REP = withoutmaternal encouragement vs with maternal encouragement; GPxREP = interaction beween GPand REP.

D I S C U S S I O N

That MA is significantly associated with each of the two measures for competence andorganization and with the relocking measures, replicates our previous results for thesituation with mother involvement (Berry, Gunn & Andrews, 1984). The finding thatthe Down syndrome group was less competent in both unlocking and relocking andshowed more aimless actions, even when MA is partialled out, may reflect a specificdeficiency for Down's syndrome which is unrelated to mental age.

A motor deficit (Frith & Frith, 1974) has been demonstrated for the syndrome,and this may be partly reflected in the locking and unlocking behaviours. Thesignificant correlation with mental age, however, suggests that the behaviours areassociated with more than a specific motor delay.

T A S K B E H A V I O U R IN D O W N ' S S Y N D R O M E 273

It is also interesting that there is no significant group difference for organizationbehaviours. This is in contrast to the results in our earlier study (Berry, Gunn &Andrews, 1984) in which fewer than half the Down's syndrome group scored at all onthis measure. There seemed to be a mental age threshold, near 22 months, which wasrequired before a score was obtained. It seems feasible that this threshold is related tothe cognitive level necessary before the child can form a mental representation of aseries of planned actions. In the present study, the majority ofthe Down's syndromechildren are older than this apparent threshold age. It seems that this may havecontributed to the narrowing of the gap between the Down syndrome and comparisonscores on pattern organization.

It also seems that once this threshold is reached, the Down's syndrome childrenare as organized in their behaviour as the comparison children. Organization may be acharacteristic of behaviour which differentiates Down's syndrome children from thementally retarded children in Goodman's (1981a) study.

The mother's influence on her Down's syndrome child's performance was notreflected in a significantly increased level of either competence or organization. Thisis despite the possibility that a practice effect might operate in the direction of such anincrease. Her influence is, however, associated with a significant decrease in aimlessactions. The comparison group displayed no behaviours which could be classifiedunder the aimless category. As Goodman (1981a) suggested, this aimless behaviourappears to differentiate the retarded from the norm and it is independent of mentalage.

The only other statistically significant result concerns the interaction betweengroup and session for successful locking. This resulted from the increase in thelocking score for the compariosn group when the mother was allowed to encourageher child. The Down's syndrome group showed a stable level of minimal performancefor this category.

The overall pattern of results confirms the usefulness of the lock box for assessingthe abilities of young children. It does not demand productive language and is morelike a play situation than a structured test. It has also revealed some behaviouraldifferences between the two groups of children which are independent of mental age.

S U M M A R Y

Twenty-one Down's syndrome children (mean CA 45.5 months, SD 12.4; mean MA24.8 months, SD 7.5) and 13 control children (mean CA 39.9 months, SD 11.6)played with a box which had 10 doors each secured by a different locking device.There were two conditions, one in which their mothers were free to interact with themand one where maternal involvement was restricted. Results showed that mental agewas significantly associated with measures of competence and organization. WhenMA was partialled out as a covariate, group differences remained for the competencemeasures, relocking behaviours, and aimless actions. The involvement ofthe motherhad a significant effect only in decreasing the aimless actions of the Down's syndromechildren.

274 P . B E R R Y and P . G U N N

REFERENCES

BEALE EM & LITTLE R J (1975) Missing values in multivariate analysis. J . R. Statist. Soc. 30,129-145.

BERRY P , GUNN P & ANDREWS RJ (1984) The behaviour of Down's syndrome children usingthe lock box: a research note. J. Child Psychol. Psychiat. 25, 125-131.

FRITH U & FRITH DC (1974) Specific motor disabilties in Down's syndrome. J. Child Psychol.Psychiat. 15, 293-301.

GOODMAN J F (1979) The lock box: an instrument to evaluate mental organization in pre-schoolchildren. J. Child Psychol. Psychiat. 20, 313-324.

GOODMAN JF (1981a) The lock box: a measure of psychomotor competence and organizedbehavior in retarded and normal pre-schoolers. J. Consult. Clin. Psychol. 49, 369-378.

GOODMAN JF (1981ft) The Goodman Lock Box Instruction Manual. Chicago, IL: Stoelting.