Working Memory, Visuospatial Memory, and Controlled Attention in

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					Working Memory, Visuospatial Memory, and Controlled Attention in Bilingual Children
               Mahchid Namazi, MSc and Elin Thordardottir, PhD
                               McGill University

In this research project involving two studies, we explored the relationship between
short-term memory, working memory, and controlled attention in young bilingual and
monolingual children. Previous research has shown that balanced bilinguals outperform
monolinguals on the Simon Task (Bialystok, 1999) – a task in which children press one
of two buttons corresponding to a shape of two different colours on the computer screen.
On congruent trials, the coloured shape and its corresponding button are on the same side.
On incongruent trials, the shape appears on the opposite side of the to be pressed button.
Measures of accuracy and reaction time are taken for both types of trials. The finding
that bilingual children are faster than their monolingual counterparts on incongruent trials
has been interpreted as bilingualism leading to an advantage in controlled attention
(Biaylstok, 1999). These studies, however, have not included measures of verbal
working memory, verbal short-term memory and visuospatial memory. We reasoned that
in addition to testing controlled attention, the Simon task places a significant demand on
working memory because children need to remember a complex rule and keep it in mind
while completing the task. This study, therefore, aims to examine the influence of verbal
working memory, verbal short-term memory, and visuospatial memory on performance
on the Simon task in order to better understand the nature of the already documented
bilingual advantage on this task.

Study 1
Background
In the first study, we compared the performance of French-English simultaneous
bilingual children with French and English monolinguals (N=45; 29 girls and 16 boys) on
the Simon Task. Groups were matched on age, nonverbal IQ, forward digit span in
English, forward digit span in French, and on visuospatial memory. The bilingual group
had a mean age of 58 months, the French monolinguals a mean age of 59.4 months, and
the English monolinguals a mean age of 58.47 months (F(2,42) = .398, p = .674). To be
included in the study, bilingual children had to have been exposed to English and French
40-60% of the time prior to age 3, with less than 5 hours per week of exposure to the
other or any other language. To be included in the monolingual group, children had to
have been exposed to English or French from birth with less than 5 hours per week of
exposure to the other or any other language. Verbal working memory was measured by
the children’s Competing Language Processing Task (Dollaghan & Campbell, 1998);
verbal short-term memory was measured using the non-word repetition task (Gathercole
& Baddeley, 1994), and visuo-spatial memory was measured by the pattern recall task
(Jarrold, Baddeley, & Hughes, 1999).

Results
Analysis of variance indicated that the groups did not differ significantly on listening
span (in English and French, p=.418), on non-word repetition (in English and French,
p=.178), or on visuospatial memory (p=.514). Therefore although the groups were
matched a priori only on age and nonverbal IQ, testing reveals that they were also
matched on verbal working memory, verbal short-term memory, and visuospatial
memory. Analysis of variance revealed no significant difference in either reaction time
(RT) or mean accuracy on either the congruent or incongruent trials of the Simon task
between the bilingual group and either monolingual group (RT congruent trials: p=.770;
RT incongruent trials: p = .851; accuracy congruent trials: p = .701; accuracy incongruent
trials: p=.787). Therefore, in contrast to previous research, a bilingual advantage was not
observed on the Simon task in groups of children that were matched on age, nonverbal
IQ, verbal short-term memory, verbal working memory, and visuospatial memory.

Univariate analysis of variance on our background measures revealed a significant
difference between groups on maternal education favouring the bilingual group:
F(2,42)=2.635, p<.01) and on receptive vocabulary favouring the English monolinguals
(F(1,28)=5.552, p<.05). For this reason, we decided to run a MANOVA with maternal
education and receptive vocabulary as covariates. These analyses also failed to reveal a
significant difference between the bilingual and monolingual groups on the Simon task.

In order to further investigate the relationship between different measures of memory and
controlled attention, we examined the bivariate correlation between verbal working
memory, verbal short-term memory, visuospatial memory, and the four measures of the
Simon Task. Results revealed significant correlations between all four Simon Task
measures and visuospatial memory as follows: RT on congruent trials, r = -.340, p<.05;
RT on incongruent trials, r = -.320, p<.05; accuracy on congruent trials, r = .516, p<.01;
accuracy on incongruent trials, r = .663, p<.01. These results indicate that children who
had higher scores on the visuospatial memory task were more accurate on the Simon task.
The results also reveal a speed-accuracy trade-off on the Simon task such that greater
accuracy was associated with higher RTs.

Study 2
Background
In the second study, we were interested in whether bilingual and monolingual children
differed in a verbal measure of auditory controlled attention. A second aim was to look
at the relationship between auditory controlled attention and verbal memory. Auditory
controlled attention here refers to attending to a speaker in one language while ignoring
an irrelevant, but meaningful, conversation taking place in the other language in the
background at a reduced volume. We could not find any study that had looked
specifically at the accuracy of sentence comprehension in bilingual children in the
context of background meaningful conversation in the other language, as compared to
their monolingual peers. Research with adult monolinguals investigating the cocktail
party phenomenon has shown that individuals with low working memory spans recall
their own name in an unattended, irrelevant message (Conway, Cowan, & Bunting,
2001). Other research has shown that older adults’ reduced efficiency in controlled
attention is a crucial factor in their difficulty in recalling target speech in the presence of
a background of competing speech (Tun, O’Kane, & Wingfield, 2002). Monolingual
children’s perception of speech in multitalker babble relative to that of adults has also
been investigated showing that children required more favorable signal to noise ratios to
achieve comparable performance in low noise (Fallon, Trehub, & Schneider, 2000).
Research with children learning English as a second language (L2) has looked at the
effect of classroom noise on attention and speech perception – word recognition
performance was reduced significantly for L2 children relative to their monolingual
English counterparts (Nelson, Khonert, Sabur, & Shaw, 2005).

We wanted to extend these findings to verbal auditory controlled attention in
simultaneous bilingual children. Participants were the same as those outlined in the first
study. Recall that the children were matched on age, nonverbal IQ, forward digit span,
verbal short-term memory, verbal working memory, and visuospatial memory. The
measure of auditory controlled attention was a computerized sentence comprehension (in
English or French) task with a competing meaningful story in the background in either
English or French. Children listened to two sets of sentences in one language (in the case
of monolinguals) or both languages (in the case of bilinguals) and touched the picture, in
a forced choice paradigm, that was associated with the sentence they heard. At the same
time, a story in one (for the first set of sentences) and then the other language (for the
second set of sentences) was played in the background at reduced loudness (10dBA)
relative to the sentences. The order of list presentation was counterbalanced. Children
were instructed to try to ignore the person who was not talking about the pictures.

Results:
Analysis of variance revealed no significant difference between either monolingual
group and the bilinguals: French sentence comprehension (with English story), p=.882;
French sentence comprehension (with French story), p=.330; English sentence
comprehension (English story), p=.201; and English sentence comprehension (with
French Story), p = .304. In the next analysis, we looked at the relationship between
performance on the auditory controlled attention task and verbal working memory
(CLPT- Competing Language Processing Task, a test of listening span) as well as verbal
short term memory (nonword repetition). We ran a bivariate correlation on the following
variables: auditory controlled attention in each language, nonword repetition in each
language, CLPT listening span in each language. For the bilingual group, there were
significant correlations between the auditory controlled attention task and listening span
in French only as follows: French sentence comprehension (with English story), r = .547,
p<.05; English sentence comprehension (with English story), r = .587, p<.05; English
sentence comprehension (with French story), r = .688, p<.01. For the French
monolingual group, there was a significant correlation between auditory controlled
attention and listening span in French for both lists as follows: English story, r = .734,
p<.01 and French story, r = .598, p<.05. There was no significant correlation between
auditory controlled attention and listening span in English for the English monolinguals.
There were also no significant correlations between nonword repetition and auditory
controlled attention for any of the groups.

Conclusions
Findings from this first study failed to confirm the bilingual advantage in controlled
attention noted in previous research. The significant correlations between performance
on the Simon Task and visuospatial memory demonstrate that children with better
visuospatial memories also have better visual controlled attention. The failure to confirm
a bilingual advantage could be due to differences in the strict matching between groups
on multiple measures as well as on how bilingualism was operationalized. In the second
study, we did not find any differences between the three groups on a measure of auditory
controlled attention. Performance on auditory controlled attention was related to number
of words recalled on the CLPT for the bilingual and French monoligual groups.
                                     Reference List

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