Bilingualism And Executive Control
With inconsistent results from various studies, identifying and quantifying the bilingual advantage, if there indeed is one, has become an increasingly controversial field of debate. Whilst initial studies proved promising; the bilingual advantage has more consistent null hypotheses with larger sample sizes and more robust testing.
Bilingualism and Executive Control
A contentious area currently under debate is the link between bilingualism and executive control (executive function used interchangeably) within the minds of children, and whether or not children benefit from bilingualism as a result. Executive control can be simplified as the various methods employed by the brain to regulate thoughts and actions (Brocki, 2007). These methods are generally agreed upon: Inhibitory control - in the case of receiving a smaller reward immediately, or waiting for a larger reward later on (not taking the immediate smaller reward would be an exercise in inhibitory control). Flexibility - one’s ability to ‘shift’ between different tasks and mental states. Updating, the ability to monitor working memory and update where new information is presented (Brocki, 2007; Miyake et al. , 2000).
Metacognition & Executive Control
These executive functions coincide with metacognitive monitoring, simply; the act of regulating one’s current cognitive activities. Ashcraft (1994) identifies the ability to monitor one’s cognitive state as metacognition, and that the awareness that adults have of their cognitive state is far greater than that seen in children. Ashcraft (1994) uses the example of an adult and a child: An adult who receives a phone number is likely to rehearse the number until they believe they have committed it to memory. However, a child is more likely to assume they will remember it, and will be perplexed upon the realisation that hearing it once was insufficient. Roebers (2017) suggests that both executive function and metacognition develop not only alongside one another, but that the two are dependent on one another between 2-6 years of age.
In order to correct themselves when they have made a mistake, they must understand consciously that they have made an error. This broader cognitive self-assessment would then lead into the executive controls such as inhibition and shifting, in order to correct the perceived mistake. It is important to note that these ‘skills’ develop over time. Hence a child may not rehearse information even if the goal demands that they memorise a piece of information (Ashcraft, 1994). Executive control and metacognitive improvement is stimulated by environmental factors. Environments that require children to complete tasks that challenge them to use these skills, actively monitoring their performance and progress. Blair et al. (2014) found that parenting and schooling can be beneficial to the development of metacognition and executive functions. Parents that encourage their children to question their actions, plans, etc. encourage the employment and development of these skills.
Whilst a student is naturally required to consider why they thought the way they did, or how they went about preparing for a test or exam, Roebers (2017) notes that the curriculum plays a significant role. 5 year old students who are challenged to be more independent, so long as adequate provisions are in place, will outperform students who attend more guided classes in both executive control skills and metacognitive skills. Reinforcing this notion, Lillard & Else-Quest (2006) conducted a study examining ‘Montessori’ education, and its effects on the development of the students. Montessori is a form of education that requires children to work independently or in small groups, deciding on material to work through themselves, and explore the curriculum with assistance from teachers. They concluded that Montessori education, with its student-centred and choice-based focus, led to better performance than standard education in both executive control and on standardized tests.
Bilingualism and Executive Control
Given the unique challenges presented in learning another language, bilingualism could, in theory, offer a challenging environment. One that stimulates the development of metacognition and executive control. Barac et al. (2014) suggest that there may be some advantages to bilingualism in the development of executive functions, specifically in cognitive flexibility and areas of inhibitory control. Kovacs and Mehler (2009, cited in Barac et al. , 2014) demonstrated that bilingual children as young as 7 months old had better control of cognitive flexibility, and were able to adapt faster to changes in the rules of a task. In terms of inhibitory control, Martin-Rhee & Bialystok (2008) distinguished between two kinds of inhibitory control: Attentional and Inhibition.
In their study, bilinguals outperform monolinguals in attention control, rather than inhibitory control as a whole. In tasks that required the participants to delay their gratification bilingual children performed similarly to monolingual children (Barac et al. , 2014; Martin-Rhee & Bialystok, 2008). However, attempts to replicate this study with similar results favouring a bilingual advantage have been inconsistent, particularly when larger sample sizes are involved (Duñabeitia et al, 2014; Kousaie et al. , 2014. ; Paap et al. , 2015; Von Bastian et al. , 2016). Similarly, Valian (2015 p. 18) states ‘In all the cases [of cognitively enriching activities] that have been examined, consistent exposure to cognitive challenges leads to better executive function. ’ As discussed previously, curricula such as the Montessori system could lead to enhancement in executive function from an early age. The Montessori style education has been a success in the United States, implemented in more than 5,000 schools across the country, benefiting the children’s executive control skills (Lillard & Else-Quest, 2006).
In monolingual areas, it may be far easier to implement this to potentially net similar results. Thus a pivotal point in the debate is the method of isolating and establishing bilingualism as a causal factor. With parenting, parent education level, teacher interaction, and curriculum having an effect on the development of cognitive skills (Lillard & Else-Quest, 2006; Blair et al. , 2014; Von Bastion et al. , 2016; Roebers, 2017) controlling for these factors becomes incredibly difficult. It is therefore not surprising that the results from studies attempting to link bilingualism and executive function have come out inconsistent (Duñabeitia et al, 2014; Kousaie et al. , 2014. ; Paap et al. , 2015; Valian, 2015; Von Bastian et al. , 2016).
Valian (2015) argues one potential source of inconsistency; that the bilingual advantage is no more advantageous than any other cognitively demanding environment. Young children are still developing their executive functions; older participants such as the 118 in Von Bastian et al. ’s (2016) study were all university students from Switzerland. They tested for three potential sources of bilingual advantage: Age of acquisition, proficiency, and usage and found no advantage from any area. Perhaps the participants, regardless of their capabilities in L2 or otherwise, were already exposed to sufficient stimuli to develop their executive functions. However, Von Bastion et al. ’s study was entirely comprised of (to varying degrees of proficiency) bilingual participants. The three groups they controlled for were separated by the extent of their usage of their L2. Von Bastian et al. (2016) conclude a few potential reasons for the inconsistent results of previous studies, and their consistent null hypothesis: That bilingual advantages only appear when tested for with specific means. They argue that if this is the case, it could be due to small sample sizes, a factor that would be unavoidable if a study were to control all variables which theoretically lead to the development of executive function. Another factor identified is task-specific effects. Von Bastian et al. (2016) argue that the advantage in their own tasks only correlate when looked at in isolation.
Once the results are examined in conjunction with the other tasks the advantage is present only in the figural-spatial task. They found a weak relation to cognitive performance, and that it was primarily related to the participants use of non-L1 languages. Bialystok (2017, p. 253) notes that not all tasks will be representative of a bilingual’s experience, and thus the executive functions that they have developed as a result. Calambria et al. (2011) support this notion, their study involved proficient bilinguals who were tested in their ability to task switch, and investigated the dependence of bilingual language control on executive control. As is consistent with prior studies (Costa et al. , 2004; Martin et al. , 2013) the participants showed symmetrical shift costs across linguistic tasks, and asymmetrical shift costs across non-linguistic tasks. Calambria et al (2011) note that whilst there is some overlap between bilingual language control and executive control, their results are contrary to them being dependent on one another.
Furthermore, Prior & Golan (2011) found that low cost task-switching in executive control was only present in bilinguals that had to switch languages frequently, somewhat parallel to Von Bastion et al. ’s (2016) study. This could suggest that the advantages entirely depend on the context of the individual bilingual’s experience, as Bialystok (2017, p. 253) suggested. Moreover, it calls into question exactly how robust the advantages of bilingualism are in terms of executive function. Bialystok acknowledges the inherent difficulty in isolating a factor of cognition. Tests that could easily and consistently demonstrate the sole benefit of bilingualism simply do not seem to exist Bialystok (2017, p. 254). Bialystok appears to argues in favour a holistic approach to the matter, whilst Valian (2015, p. 19) argues that there should be more focused research into the individual mechanisms of executive control. Yet there are many factors indeed. Given the participants in Von Bastion et al. (2016)’s study, and that there was no significant benefit to the extent of bilingualism, it may be possible that external factors contributing to the development of executive control coincided with or superseded the benefits of bilingualism. Paap et al. (2014, p. 634) further argue that the demanding nature of communicating in a single language may be enough to develop executive control skills, and also emphasise the difficulty in isolating one difficult and demanding task from any other, in their example, playing a musical instrument.
Conclusion
At face value, it is plausible that bilingualism would offer some benefit in the development of executive function, and most certainly in language control. However, given the inconsistent results in subsequent studies and the inability to control for task-specific effects, these benefits are incredibly difficult to isolate. If bilingualism is not a categorical variable as Bialystok (2017) suggests, then comparing it to the myriad of factors which also appear to improve executive function becomes difficult. If only certain tasks which account for the bilingual experience can be used, these tasks ought to be compiled and extensively studied with a wide range of participants in order to dispel the task-specific effects and criticisms of small sample sizes.
Moreover, if these advantages are only driven through the specific way in which bilinguals use their language, as was found in the study by Von Bastion et al. (2016), the benefits would not be nearly as robust as was originally suggested. Valian’s (2015, p. 19) proposal of a more systematic approach could potentially identify why varying levels of bilingualism did not significantly impact executive control skills, perhaps there is a point of diminishing returns within bilinguals. This could explain the lack of difference between participants in Von Bastion et al. ’s (2016) study. Creating control groups for such a wide range of factors (parental education, parental interaction, the type of education the participants receive and even their usage of their bilingualism) would be a colossal task - if even ethically permissible in some cases. It would seem that the exact benefits of bilingualism, and the applicability of previous results to be generalised to a larger population, are still in question and will require much more detailed research.
