Last class, Daniella gave a presentation about how bilingualism effects executive function in young children. The study she discussed happened in 2007, and as we discussed, researchers determined a slight advantage to being bilingual, but there was not conclusive evidence.

Fast forward to 2011, Poulin-Dubois and her fellow researchers were eager to determine at what age a bilingual advantage becomes apparent, and in what ways does this advantage manifest?

Many studies that suggest bilingual children and adults possess some advantages over their monolingual peers. There has long been interest in determining whether bilingualism leads to linguistic or cognitive differences in both children and adults. Research over the past two decades has revealed a number of differences that emerge from growing up with at least two languages. Generally, bilingualism leads to the development of strategies that are adaptive to the unique problem space with which bilingual infants are faced.

More surprising is the evidence showing that bilingualism also leads to the precocious development of cognitive processes not confined to linguistic tasks. In a comprehensive review of the research on cognitive differences between bilingual and monolingual children, Bialystok (2001) concluded that there is growing evidence that bilingual children outperform monolingual children on a variety of tasks that require selective attention and cognitive flexibility tasks.

Research with children (Bialystok, 2005) and adults (Bialystok, Craik, Klein, & Viswanathan, 2004) has shown that bilinguals show better control over these executive processes than their monolingual counterparts. In children as young as 4 years of age, this advantage has been demonstrated with a range of tasks typically used to assess executive functioning.
The prevailing interpretation of the bilingual advantage in executive control is that bilinguals have extensive practice in exercising selective attention and cognitive flexibility. This practice effect is assumed to derive from the fact that both languages are active when one of them is being used.

At what point do the inhibition and selective attention abilities of bilingual children deviate from the developmental trajectory of monolingual children? For the management of attention to two languages to lead to modifications in executive functioning, it would be necessary for children to differentiate between the two languages.

63 children aged 24 months were divided into monolinguals and bilinguals based on exposure to their L1. Nearly all of the children were from Caucasian families who lived in the same middle-class neighborhood in a large Canadian city. All bilinguals had been exposed to two languages from birth.

The children were placed into the two different category groups based on their exposure to their first language. This was determined by asking parents the amount of language(s) the child may have had exposure to based on their interactions with caregivers and other possible people they came in contact with regularly. Also, to make sure that both group of children were at similar cognitive levels the caregivers were asked to evaluate how many words the child knew by picking from a list provided.

The children were given five test. Three of them were conflict tasks and two were delay tasks: 1. Multilocation:
This test consisted of a wooden box that had three unlocked drawers and two locked ones not used for the experiment. A cracker would be hid in one drawer and the child would be told where it was and where not to look. The child then was told to find the treat after a towel was placed under the box. For the second part of the test, the cracker was hid in another drawer and the same procedure was followed. The only difference was a ten second delay before giving the child the box to find the cracker.
2. Shape Stroop:
For this experiment, there were two picture copies of an apple, banana and orange. One of each was small and the other one was large. After identifying all of them, they paired them by choosing a small fruit picture and placing it on top of a different large fruit picture. The children were then asked to point out the small fruits. An example of this would be " Can you point to the small banana?"
3. Reverse Categorization:
Two Buckets were presented to a child without labeling which one was the small or big bucket. After 12 cubes were given to the child to play with for a minute and then taken away. The buckets were taken out and the experiment explained to put all big blocks in the bigger bucket and the small blocks in the smaller bucket. The child was able to practice this and then the game was reversed. The child had to put the big cubes in the smaller bucket and the small cubes in the bigger bucket.
4. Snack Delay:
A snack (cereal) was placed on a plate and then covered by a plastic see through cup. The child was told to wait until the bell rang in order to eat it the piece and have more. The test was repeated several times.
5. Gift Delay:
After all the other four experiments were done, the experimenter would place a gift back in front of the child and state it was for them but mention that they were going to go find a bow for it. The experimenter measured how much time it took for the child to look inside the bag or the time it took for the experimenter to walk into the room.

When the children were evaluated for their word count (done by parents), both groups had about the same score for the number of words regardless of the category they were placed under. This was done so that one group would not have an unfair advantage over the other.

Here are the results for the five cognitive tests that were performed.

1.Multilocation
The two groups did worse during the second part of the test.
3.Reverse Categorization
The children were not able to complete the second part.
4.Snack Delay
The results for this test were not significant for gender or language difference.
5.Gift Delay Task
The girls waited longer to open the gift than boys but nothing significant to language.

For the Executive functioning tasks, the Multilocation and the Reverse Categorization tasks were too difficult for this age group to complete. The delay tasks did not have any significance for language differences. They were performed to test for other executive function abilities for the toddlers.

These scores reflect the correct scores from the first and second stroop tests administered to the subjects. As you can see, monolingual and bilingual children score approximately the same on the first test. In the second test, bilingual children scored significantly higher.

The results of this study confirm the specificity of bilingual effects to conflict tasks in older children and demonstrate that bilingual advantages in executive control emerge at an age not previously shown.