Cognitive effects of bilingualism
Research on executive functions like working memory, perception, and attentional and inhibitory control, suggests that bilinguals can benefit from significant cognitive advantages over monolingual peers in various settings.
[9] Systematic reviews and meta-analyses of executive functioning studies have failed to find compelling evidence for cognitive advantages in healthy adults[10] or in participants across a broader age range.
"[15] Following studies reported that bilinguals performed worse in IQ tests and suffered in most aspects of language development.
[14][15] Researchers began to change tone in the late 1950s/early 1960s, when Lenneberg, Chomsky, and Halle co-founded the field of biolinguistics and explored the role of biology in language.
In continuation of this study, research after this point began to shift focus, investigating areas of cognitive development and aptitude like perception and executive functioning.
[17] In 1977 the American Institutes for Research published an influential study which discussed bilingualism as it relates to education - how it affects a child's performance compared to peers.
Since the late 1970s, researchers have found more cognitive benefits of bilingualism, including better attention, task-switching, and protection against aging declines.
[23][26] Notably, some scientists continue to debate whether a bilingual advantage in executive functioning exists, with some studies and meta-analyses coming to opposite conclusions.
[28] In 1998, David Green proposed his "inhibitory control model",[29] which references a bilingual's constant need to suppress one language while using another.
They administered Raven's Progressive Matrices, a set of non-verbal tests designed to measure cognitive ability, to a bilingual sample of children.
Results showed their sample had a higher correlation with the degree of bilingualism, or language proficiency, and test scores.
[30] Some opposing researchers argue that correlations between bilingualism and executive function are inconsistent due to a reliance on findings with small sample sizes, publication bias,[33] and non-uniform definitions.
[56] Contributing factors include education, occupational status, higher socioeconomic class, and doing physical, intellectual and social activities.
After controlling for various cognitive factors, the researchers found bilinguals experienced later onset of symptoms and were diagnosed approximately 3–4 years later on average than monolinguals.
[63] Note that the studies did not show that bilingualism directly prevents one from having AD, but rather enables functional cognition for a longer period of time, delaying symptom onset for those with the disease.
For example, Abutalebi et al. (2015)[65] used the flanker test to study unimodal bilinguals and monolinguals matched based on education level and SES.
While this study had a relatively small sample size, the results did confirm previous research findings: the bilinguals outperformed the monolinguals on all experimental tasks, and the monolinguals' neural imaging showed more signs of age-related effects on performance of tasks and less gray matter density, which is associated with memory and function losses.
[66] Native bilingual children who develop proficiency in L1 and L2 at the same time, perform better on executive function tasks such as the Attention Network Test, which measures attentional control, compared to their late bilingual and monolingual counterparts in studies controlled for age, verbal ability, and SES.
Leopold considered that perhaps this loose connection between the meaning and form of a word could result in more abstract thinking or greater mental flexibility for bilingual children.
[68] Following this study, several others were formed to test similar things and find out more about the mental abilities of bilinguals with relation to their languages.
Anita Ianco-Worrall, author of Bilingualism and Cognitive Development,[69] designed a study to test Leopold's[68] observations and was able to replicate them.
In their book In Other Words, Ellen Bialystok and Kenji Hakuta, both professors studying bilingualism, examined the idea that "the knowledge of two languages is greater than the sum of its parts."
[70] These areas are quite difficult for a child to learn, but with development through childhood, have been shown to increase the understanding the structure of language and introduce a greater awareness of meaning.
In addition, the need to select the appropriate language system makes ordinary linguistic processing more effortful.
The simple act of retrieving a common word is more effortful for bilinguals than monolinguals due to the competition of the two languages.
For example, the research team found that monolingual and bilingual 6-year-olds in their study had similar scores on English words that were associated with schooling.
For example, in immersion contexts, the individual experiences reduced access to L1 and extensive contact with L2, which affects and facilitates processing of L2.
For example, Alguien disparó al hijo de la actriz que estaba en el balcón = Someone shot the son of the actress who was on the balcony.
[40][82] The researchers found that Spanish-English bilinguals in a Spanish-speaking environment showed preference for the typical Spanish high-attachment strategy.
However, Spanish-English bilinguals in an English-speaking environment showed preference for the typical English low-attachment strategy, even when reading the phrase in Spanish, their dominant language.
