Cognitive Development

It was once believed that learning two languages early in life had a negative effect for development. Learning two languages at once was thought to confuse children, interfere with cognitive functions and inhibit school achievement. However, in the past several decades an explosion of research on bilingual children has demonstrated that bilingualism actually has positive effects for cognitive function. Bilingual children are better able to deal with verbal and linguistics abilities, general reasoning concepts, formation of divergent thinking, and metalinguistics skills.

Executive Control

Executive control consists of inhibition, task switching, cognitive flexibility, and updating information in working memory. Studies have shown that bilingual children perform better than monolingual children on tests that measure executive control, and that these differences persist throughout the lifespan. According to Bialystock (2009), executive control abilities develop earlier in children, are more efficient throughout the lifespan, and decline more slowly with aging for bilingual individuals.


Production of two separate languages involves the executive control system because the child must switch constantly switch attention to the target language (Bialystock 2009). This may lead to the executive control system being more efficient in other areas as well.

How do we know?

Many studies have investigated differences in bilingual and monolingual children's performances on various tasks that measure executive control. For example, Bialystock (1988) found that bilingual children performed better in detecting grammatical errors that required controlled attention and inhibition. This finding extended to nonverbal tasks as well: bilingual children were able to solve problems that contained conflicting cues compared to monolinguals (Zelazo, Frye and Rapus 1996). These tasks involved attending to certain features and ignoring irrelavent stimuli to sort stimuli by different features (such as color or shape). Bilingual children have also been found to have faster reaction times for solving problems (Bialystock 2009)

Divergent Thinking

Divergent thinking is the process where there is a broad search for information followed by the generation of multiple answers to a problem, according to Guilford (as cited in Kharkhurin, 2008, p. 225). It is believed to be an unconscious ability where the individual is able to simultaneously process a large number of distant concepts. Bilingualism has been found to improve three aspects of unconscious divergent thinking: fluency, flexibility and elaborate thinking (Kharkhurin 2008). However, bilingual individuals did not differ from monolinguals on tasks that required producing creative and original ideas.


Divergent thinking is largely an unconscious ability that involves simultaneously generating many unrelated concepts. Researchers propose that the architecture of the bilingual memory may be the basis for improved divergent thinking, according to Kharkhurin (2008). Translating between languages may lead to a more elaborative “language mediated concept activation” in bilingual people. This is basically a mechanism in the brain that allows people to process multiple language-related concepts at once. If bilinguals have more efficient language mediated concept activation, this may generalize to non-linguistic tasks. More research is needed to establish exactly why bilingual people have better divergent thinking skills.

[section on why they are not more creative]

How do we know?

Kharkhurin tested four aspects of divergent thinking:

  • Fluency: The ability to produce a multitude of ideas or solutions.
  • Flexibility: the ability to process information in different ways, with the same stimulus
  • Elaboration: the ability to enhance ideas with details
  • Originality: the ability to produce new or uncommon ideas

Bilingual children performed better on tasks measuring fluency, flexibility, and elaboration but not originality. Bilinguals have a language asset over monolinguals and are more simplistic in concept formation, spatial analysis, and have larger mental flexibility. The variables were measured with established divergent thinking measures. The tasks involve giving participants scenarios and asking questions and giving directions to draw specific figures or pictures.

The results of this study indicate that bilingualism may improve speed and efficiency of processing and producing information, but not the ability to come up with unique and novel ideas. The authors of this study postulate that this is because creativity/originality is more related to personality whereas fluency, flexibility and elaboration are more learned and can be improved (Kharkhurin 2008)

Theory of Mind

Theory of mind refers to the ability to interpret other people's behavior through their internal mental states, which consist of intentions, beliefs and desires (Goetz 2003). This skill begins to develop around the age of 2 and improves as the child gets older. Bilingual three and four year old children were found to perform significantly better on theory of mind tasks compared to their monolingual peers, in a study by Goetz (2003).


Bilingual children have more metalinguistic awareness: they are able to think about languages in a way the monolingual children may not be able to, as a result of knowing two or more languages. This may help children understand that an object or event can be represented in more than one way, which can generalize non-linguistic situations, such as in interpreting other's thoughts or actions (Goetz 2003)

Bilingual children are also often exposed to different sociolinguistic contexts, such as the home/family and school or daycare. They may be more aware than monolingual peers of matching their language to their linguistic partners. These increased sociolinguistic demands may affect cognitive abilities, namely theory of mind.

How do we know?

Goetz (2003) tested multiple aspects of theory of mind on bilingual and monolingual children of different ages. Appearance reality tasks show the child an object that looks like one thing, but is actually another. A child with better theory of mind abilities can name what the object appears as and what it really is. Perspective-taking tasks test if the child can understand that a picture may appear differently to another person if it is facing a different way. False belief tasks test the ability to understand that someone else may not have the knowledge that you have. for example, a child was shown a box of M&Ms that contained a toy car. Then he was asked what someone else who had never looked inside the box would think was inside the M&M box. If a child has theory of mind abilities, he should understand that someone else will probably think there are M&Ms in the box.

Goetz found that older children performed better on these tasks than younger children, which was expected because theory of mind abilities develop with age. They also found that bilingual children perform better on these tasks, which supports the above theory that metalinguistic awareness and different sociolinguistic contexts may affect cognitive abilities.

Confounding Variables

This consistent bilingual advantage may be confounded be environmental variables such as socioeconomic status (SES) or cultural and ethnic backgrounds. For example, Korean and Chinese children often perform better than American children on executive control tasks, because of different values and emphasis on intelligence in their culture. Bilingual children may be more likely to come from this type of cultural background or to be from high SES families.

Is there really a unique effect of bilingualism on cognitive function or is it explained by other factors? Yang, Yang and Lust (2011) attempted to answer this question by testing monolingual speakers of English and Korean and bilingual speakers of Korean, controlling for SES. Bilinguals outperformed both monolingual groups, supporting the theory that bilingualism leads to improved cognitive functioning. Korean monolinguals performed better than English monolinguals, which also provides evidence that culture plays a role in executive function as well. When studying bilingualism, culture and SES should always be controlled for (Yang, Yang & Lust 2011)