The bilingual adaptation: How minds accommodate experience

Interactions between genome and environment cause DNA methylation changes that can be transmitted to offspring of rats raised in stimulating environments.

“More dramatically, interactions between the genome and the environment lead to changes in DNA methylation that allow these changes to be transmitted to the offspring of the rats who had been raised in stimulating environments, supporting the crucial role of epigenetic factors in brain and cognitive outcomes (Mychasiuk et al. 2012).”

• cites Mychasiuk et al. 2012Not checked yet

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Engagement in particular activities such as music training, spatial navigation, action video game playing, and juggling can modify brain and cognition in humans.

“Beyond systemic environmental effects, engagement in particular activities can also modify brain and cognition in humans. These activities include music training (Lappe, Trainor, Herholz, & Pantev, 2011; Peretz & Zatorre, 2005; Rauscher, Shaw, & Ky, 1993), experience in spatial navigation (Maguire et al., 2000), extended engagement in action video game playing (Bavelier & Davidson, 2013; Green & B”

• cites Lappe, Trainor, Herholz, & Pantev, 2011; Peretz & Zatorre, 2005; Rauscher, Shaw, & Ky, 1993Not checked yet

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• cites Maguire et al., 2000Not checked yet

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• cites Bavelier & Davidson, 2013; Green & Bavelier, 2003; Karle, Watter, & Shedden, 2010; Riesenhuber, 2004Not checked yet

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Joint activation requires a mechanism for language selection to assure fluent use of the target language.

“Joint activation requires that there is a mechanism for language selection to assure that use of the target language proceeds fluently.”

The environment plays a crucial role in animals' brain and mental development.

“It is abundantly clear that the environment plays a crucial role in the brain and mental development of animals.”

Bilingualism is an experience that can modify brain and cognitive systems more generally, as enriched cages do for rats and socioeconomic status does for young children.

“Thus, the argument is that bilingualism is an experience that has the potential to modify brain and cognitive systems more generally, much as enriched cages do for rats and socioeconomic status does for young children.”

• AssumptionThe authors state this as an assumption: The mechanism for language selection is part of a domain-general process.
• AssumptionThe authors state this as an assumption: Constant engagement of the language-selection process strengthens it for other purposes, including nonverbal ones.

The best account of bilingual cognitive effects will be centered in the attention system.

“The position that will be advanced in the present review is that ultimately the best account will be one that is centered in the attention system (see discussion in Section 3.2).”

An account based on inhibition of the non-target language became the dominant explanation for bilingual effects on cognition.

“An account based on inhibition of the non-target language became the dominant explanation for bilingual effects on cognition (e.g., Bialystok et al., 2009).”

• cites Bialystok et al., 2009Not checked yet

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• AssumptionThe authors state this as an assumption: Inhibition is at least part of the mechanism for bilingual effects on cognition.

Neuroimaging evidence shows overlap in brain networks involved in language selection and nonverbal task switching.

“Support for the notion that a domain-general system is recruited for language control comes from neuroimaging evidence showing overlap in brain networks involved in language selection and nonverbal task switching (Abutalebi & Green, 2007; De Baene, Duyck, Brass, & Carreiras, 2015; Luk, Green Abutalebi, & Grady, 2012).”

• cites Abutalebi & Green, 2007; De Baene, Duyck, Brass, & Carreiras, 2015; Luk, Green Abutalebi, & Grady, 2012Not checked yet

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Learning a second language leaves structural traces in brain regions responsible for language acquisition and use.

“Together these studies demonstrate that the experience of learning a second language leaves structural traces in the brain in those regions responsible for language acquisition and use.”

Using language engages most of the brain, including frontal, temporal, and parietal lobes and some posterior regions.

“Finally, language use is integrative; using language engages most of the brain, including frontal, temporal, and parietal lobes, as well as some posterior regions (Friederici, 2011).”

• cites Friederici, 2011Not checked yet

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Bilingual infants' detection of language switches is based on a coherent concept of a language system, not on association with a particular familiar language.

“Thus, their response is based on a coherent concept of a language system and not on an association to a particular language with which they are familiar.”

Learning a foreign language produces reliable differences in brain structure, including grey matter density and white matter integrity, even after brief periods.

“In an extensive review of the literature, Li, Legault, and Litcofsky (2014) describe the reliable differences in brain structure for both grey matter density and white matter integrity following even brief periods of second-language learning.”

• cites Li, Legault, and Litcofsky (2014)Not checked yet

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No single explanation of the control mechanisms responsible for bilingual language processing and cognitive effects has emerged as decisive.

“No single explanation of the control mechanisms responsible for bilingual language processing and hence cognitive effects of bilingualism has emerged as decisive.”

English-ASL bilinguals showed priming from a repeated hand shape even though it was irrelevant to a semantic judgment task.

“The results again indicated priming from the repeated hand shape, even though it was irrelevant to the semantic judgment task.”

• cites Morford et al., 2011Not checked yet

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Because language use involves more than language-specific processes, experience-related effects of language use may generalize beyond language.

“This extensive involvement of brain centers increases the possibility that experience-related effects found for language use have the potential to generalize beyond language because the experience itself involves more than just language-specific processes.”

Language use is the most intense, sustained, and integrative experience in which humans engage.

“Language use is the most intense, sustained, and integrative experience in which humans engage.”

Three types of recent evidence converge on the conclusion that environmental differences in infancy have measurable consequences for nonverbal outcomes.

“Three types of recent evidence converge on the conclusion that they do.”

Six-month-old infants in bilingual environments show better stimulus encoding and recognition memory than monolingually raised infants.

“Similarly, a study of 6-month-old infants engaged in a visual habituation task demonstrated better stimulus encoding and recognition memory by infants raised in bilingual environments than for their monolingually-raised counterparts (Singh et al., 2015).”

• cites Singh et al., 2015Not checked yet

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A 9-month longitudinal foreign language learning study found changes in white matter integrity in left hemisphere language areas, their right hemisphere analogs, and frontal lobe.

“For example, Schlegel et al. (2012) reported evidence from a 9-month longitudinal study of foreign language learning that found changes in white matter integrity in left hemisphere language areas and their right hemisphere analogs as well as in the frontal lobe over the course of the study.”

• cites Schlegel et al. (2012)Not checked yet

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The bilingual mind must adapt to jointly activated languages for communication to proceed.

“Thus, the bilingual mind must adapt to this mental configuration that includes jointly-activated languages in order for communication to proceed.”

To achieve fluent linguistic performance, bilinguals experience greater demands on a control system than monolinguals, even when language production appears equivalent.

“To achieve fluent linguistic performance, therefore, bilinguals experience greater demands on a control system than do monolinguals, even when language production appears to be equivalent.”

Both languages in a bilingual's repertoire are always active to some extent, even when one is not required by the current context.

“The key point comes from overwhelming evidence that both languages in a bilingual’s repertoire are always active to some extent, even if one of them is not required for the current context.”

• cites Costa, Caramazza, & Sebastian-Galles, 2000; Costa, Santesteban, & Ivanova, 2006; Dijkstra, Grainger, & van Heuven, 1999; Hermans, Bongaerts, de Bot, & Schreuder, 1998Not checked yet

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• cites Kroll, Dussias, Bice, and Perrotti (2015)Not checked yet

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Together with infant studies, the finding of bilingual advantages in children as young as 2 years casts doubt on inhibition of a non-target language as the source of processing differences in bilinguals.

“Together with the infant studies, these results cast doubt on the role of inhibition of a non-target language as a likely source of processing differences in bilinguals.”

• AssumptionThe authors state this as an assumption: Inhibition is at least part of the mechanism for bilingual effects on cognition.

The majority of research with children using executive function tasks shows that bilinguals generally perform better than comparable monolinguals.

“To summarize, the majority of research with children based on tasks that are used in the investigation of executive functioning show that bilinguals generally perform better than comparable monolinguals.”

• AssumptionRests on an assumption: The bilingual and monolingual groups in the reviewed between-groups studies are equivalent on relevant background variables.

Early exposure to a bilingual environment promotes earlier development of a flexible attention system.

“Together these findings suggest that early exposure to a bilingual environment promotes the earlier development of a flexible attention system.”

The reviewed between-groups studies almost exclusively require assumptions about the equivalence of the groups.

“These studies are almost exclusively based on between-groups comparisons that require assumptions about the equivalence of the groups.”

A longitudinal study of 9- to 10-year-olds showed that level of bilingualism predicted the increase in executive control within the same children over one year.

“The second is also a longitudinal study that studied children over a one-year period between 9- and 10-years old and showed that level of bilingualism predicted the increase in level of executive control within the same children (Riggs et al., 2014).”

• cites Riggs et al., 2014Not checked yet

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In the majority of studies, bilingual children perform conflict or switching tasks better than monolingual children, although there are exceptions.

“The general finding is that bilingual children perform these tasks better than monolingual children, although there are exceptions that will be discussed.”

• cites Barac, Bialystok, Castro, & Sanchez, 2014Not checked yet

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• cites Adesope, Lavin, Thompson, & Ungerleider, 2010Not checked yet

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In two studies, bilingual children were able to abandon an initial interpretation of an ambiguous figure with fewer cues than monolingual children.

“In two studies, bilingual children were able to do this with fewer cues than were monolingual children (Bialystok & Shapero, 2005; Wimmer & Marx, 2014).”

• cites Bialystok & Shapero, 2005Not checked yet

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• cites Wimmer & Marx, 2014Not checked yet

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Evidence that bilingualism is the relevant factor comes from studies manipulating both bilingualism and country of origin.

“Moreover, evidence for bilingualism being the relevant factor comes from studies in which both bilingualism and country of origin are manipulated, as shown in the study by Yang et al. (2011) described in Section 2.1.2.1.”

• cites Yang et al. (2011)Not checked yet

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The unusually wide age range in the Anton et al. and Dunabeitia et al. studies might partly explain why their results differ from other studies.

“These studies both included children over a 6-year age range from approximately 6- to 12-years old (possibly the same children in both studies reducing the independence of the contributions), and the unusually wide age range might be part of the reason that the results are different from those found in other studies.”

Several studies have demonstrated better performance by bilingual children than monolingual peers on the Dimensional Change Card Sort Task.

“Several studies have demonstrated better performance in this task by bilingual children than by their monolingual peers (Bialystok, 1999; Bialystok & Martin, 2004; Carlson & Meltzoff, 2008; Kalashnikova & Mattock, 2014; Okanda, Moriguchi, & Itakura, 2010).”

• cites Bialystok, 1999Not checked yet

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• cites Bialystok & Martin, 2004Not checked yet

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• cites Carlson & Meltzoff, 2008Not checked yet

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The dissociation also challenges the notion that inhibition is a single factor in executive function.

“It also challenges the notion that inhibition is a single factor in conceptions of the executive function.”

In the first two years of life, infants raised in multilingual environments display different patterns of visual attention from those raised in monolingual homes.

“These studies examining detection of language switches, visual response to spatial position for reward, and memory generalization converge on the interpretation that in the first two years of life infants being raised in multilingual environments display different patterns of visual attention from those raised in monolingual homes.”

The dissociation in response patterns between two types of inhibition tasks casts doubt on inhibition as a mechanism for bilingual effects on cognition.

“This dissociation in the response patterns between two types of tasks widely considered to be tests of inhibition casts doubt on the utility of the concept of inhibition as a mechanism for the bilingual effects on cognition.”

Recent research reports bilingual advantages in cognitive processing in children as young as 2 years.

“However, more recent research has reported these patterns in children as young as 2-years (Bialystok, Barac, Blaye, & Poulin-Dubois, 2010a; Poulin-Dubois, Blaye, Coutya, & Bialystok, 2011).”

• cites Bialystok, Barac, Blaye, & Poulin-Dubois, 2010aNot checked yet

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• cites Poulin-Dubois, Blaye, Coutya, & Bialystok, 2011Not checked yet

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In children in immersion education programs aged about 7-10, executive function performance was predicted by degree of bilingualism.

“Finally, a study of children in immersion education programs also indicated that performance on executive function tasks from about 7- to 10-years old was predicted by their degree of bilingualism (Bialystok & Barac, 2012).”

• cites Bialystok & Barac, 2012Not checked yet

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Four studies examined the relation between bilingualism and executive function within the same children as a function of their level of bilingualism.

“Four studies have taken a different approach and examined the relation between bilingualism and executive function performance within the same children as a function of their level of bilingualism.”

• cites Crivello et al., 2016Not checked yet

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• cites Riggs et al., 2014Not checked yet

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• cites Thomas-Sunesson, Hakuta, & Bialystok, in pressNot checked yet

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A longitudinal study found that children who became more bilingual between 24 and 31 months showed the largest advantage over monolingual children on a battery of executive function tasks at 31 months.

“The first is a longitudinal study that tested children at 24 months and 31 months and found that children who became more bilingual over this period showed the largest advantage over monolingual children performing a battery of executive function tasks at 31 months (Crivello et al., 2016).”

• cites Crivello et al., 2016Not checked yet

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Some studies found no significant difference attributable to language background on children's ANT, flanker, or Stroop tasks.

“Some studies using these tasks have not found these effects. Carlson and Meltzoff (2008) tested 6-year-olds who were monolingual, bilingual, or attending a language immersion program and found no significant difference in performance on the flanker task, although they did show better bilingual performance on other conflict tasks in their battery. Two studies by another group also failed to find”

• cites Carlson and Meltzoff (2008)Not checked yet

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• cites Anton et al., 2014Not checked yet

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• cites Dunabeitia et al., 2014Not checked yet

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Bilingual Spanish-Catalan young adults had significantly greater grey matter volume in Heschl's gyrus than monolingual Spanish young adults.

“Ressel et al. (2012) examined grey matter density in Heschl's gyrus, a region involved in auditory and linguistic processing, for monolingual (Spanish) and bilingual (Spanish-Catalan) young adults. The results showed significantly greater volume in the bilinguals than in the monolinguals.”

• cites Ressel et al. (2012)Not checked yet

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Compared with bilinguals, highly skilled simultaneous interpreters had lower grey matter density in the left middle-anterior cingulate gyrus and inferior parietal gyrus.

“They found differences in grey matter volume in many of the regions discussed above, including left middle-anterior cingulate gyrus and the inferior parietal gyrus, but in this case, the density was lower for the interpreters than for the bilinguals.”

• cites Elmer et al. (2014)Not checked yet

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Monolinguals and bilinguals performing simple executive function tasks engage different brain regions or networks, whether behavioral performance is similar or not.

“Thus, monolinguals and bilinguals performing simple executive function tasks engage different brain regions or networks and importantly, these differences were closely tied to cognitive functions that have been predicted to be affected by bilingualism.”

Despite counterexamples, there is compelling consistency that bilingualism modifies brain regions involved in language processing and attention to language systems.

“However, even with the notable counterexamples, there is a compelling consistency in which brain regions that are involved in language processing and attention to language systems are modified by bilingualism.”

Higher fractional anisotropy in the superior longitudinal fasciculus correlated with longer time in a language immersion program for Chinese students learning English.

“Mamiya, Richards, Coe, Eichler, and Kuhl (in press) reported a correlation between higher FA values in the superior longitudinal fasciculus and length of time spent in a language immersion program for Chinese students learning English.”

• cites Mamiya, Richards, Coe, Eichler, and Kuhl (in press)Not checked yet

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Neuroimaging outcomes showing greater structural density in bilinguals or functional patterns resembling older children/adults are evidence for better brain development in bilinguals.

“In general, outcomes from neuroimaging that show greater structural density in bilinguals or functional patterns in bilingual children that resemble those obtained from older children or adults are evidence for better brain development in bilinguals.”

• AssumptionRests on an assumption: Neuroimaging differences between monolinguals and bilinguals reflect meaningful cognitive differences rather than epiphenomena.

However, many studies do not show these effects, especially for young adults.

“However, many studies do not show these effects, especially for young adults.”

Neuroimaging studies of monolingual and bilingual children show differences in both structural and functional measures.

“Neuroimaging data from monolingual and bilingual children are limited, but the studies that exist show differences in both structural and functional measures.”

For older adults, monolinguals and bilinguals do not differ significantly in anterior temporal pole grey matter volume.

“A study by Olsen et al. (2015) found no significant difference between monolingual and bilingual older adults in the anterior temporal pole”

• cites Olsen et al. (2015)Not checked yet

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Bilingual older adults had greater frontal lobe white matter volume than monolinguals.

“a study by Olsen et al. (2015) examining white matter volume (rather than FA) found that bilinguals had greater frontal lobe white matter than did monolinguals, supporting claims for better frontal functioning in bilinguals.”

• cites Olsen et al. (2015)Not checked yet

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In the anterior temporal pole, bilingual older adults retain more grey matter density than matched monolinguals.

“Abutalebi et al. (2014) reported that bilinguals showed better preserved grey matter density than comparable monolinguals in the anterior temporal pole, a region important for conceptualization.”

• cites Abutalebi et al. (2014)Not checked yet

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In young adults, bilinguals showed greater fractional anisotropy than monolinguals in corpus callosum tracts reaching the inferior fronto-occipital fasciculus and superior longitudinal fasciculi.

“Similar results were reported by Pliatsikis, Moschopoulou, and Saddy (2015) for young adults, with higher FA found across the corpus callosum extending to inferior fronto-occipital fasciculus and the superior longitudinal fasciculi.”

• cites Pliatsikis, Moschopoulou, and Saddy (2015)Not checked yet

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For white matter, bilinguals generally show better integrity in several tracts, especially inter-hemisphere and anterior-to-medial tracts.

“For white matter, bilinguals generally show better integrity in several tracts, notably those involved with inter-hemisphere connectivity and anterior to medial tracts.”

Unlike behavioral studies, neuroimaging studies comparing monolingual and bilingual adults routinely report group differences in brain structure and function.

“Unlike evidence from behavioral studies, neuroimaging studies comparing monolingual and bilingual adults routinely report group differences in brain structure and function.”

Frontal lobe white matter volume was positively related to Stroop task performance.

“In fact, white matter volume in the frontal lobe was positively related to performance on a Stroop task.”

• cites Olsen et al. (2015)Not checked yet

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Frontal regions are plausible candidates for neuroplastic changes from bilingualism because of their role in controlled processing.

“Frontal regions are plausible candidates for neuroplastic changes from bilingualism because of the role of the frontal lobe in the controlled processing in which bilinguals typically excel.”

The Abutalebi and Olsen findings support the idea that bilingualism shields against age-related grey matter loss in frontal regions.

“The results of the Abutalebi et al. and Olsen et al. studies are consistent with the interpretation that bilingualism offers protection against loss of grey matter volume in frontal regions with aging.”

• cites Abutalebi et al.Not checked yet

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• cites Olsen et al.Not checked yet

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• AssumptionRests on an assumption: Differences in brain structure and function between monolinguals and bilinguals reflect the causal effect of bilingual experience rather than pre-existing differences.

The ERP results provide substantial evidence for better bilingual processing in specific components related to general attention or executive function.

“The ERP results from these studies provide substantial evidence for better bilingual processing in specific components of these tasks that are related to general attention or executive function.”

By controlling for performance, brain differences can be interpreted in terms of processing efficiency.

“By controlling for performance, brain differences can be interpreted in terms of processing efficiency (e.g., Abutalebi et al., 2012; Gold et al., 2013a), something not possible if both brain function and behavioral performance are different.”

• cites Abutalebi et al., 2012Not checked yet

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• cites Gold et al., 2013aNot checked yet

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In Gold et al. (2013a), bilinguals showed decreased activation in left frontal and cingulate cortex in both younger and older adults during a perceptual switching task.

“In both age groups, bilinguals showed decreased activation in the left frontal and cingulate cortex (cf., Abutalebi et al., 2012).”

• cites Gold et al. (2013a)Not checked yet

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Bilingual young adults had better white matter connectivity than monolinguals in similar regions, in the left hemisphere.

“Garcia-Penton et al. (2015) also found better white matter connectivity in bilingual young adults than monolinguals in similar regions, but this time in tracts in the left hemisphere.”

• cites Garcia-Penton et al. (2015)Not checked yet

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Age of second-language acquisition, second-language proficiency, and other factors moderate the effects of bilingualism on brain structure.

“Some studies have shown moderating influences of age of acquisition of a second language, proficiency in the second language, and other such factors, leading to a more complex view.”

The summary of research with infants and children is that development of abilities broadly associated with executive functioning is more precocious in bilingual children than monolingual counterparts.

“The summary of the research with infants and children is that the development of abilities broadly associated with executive functioning is more precocious in bilingual children than in their monolingual counterparts.”

These studies show that both younger and older bilinguals generally outperform monolinguals on a range of executive function tasks.

“These studies show that both younger and older bilinguals generally outperform monolinguals on a range of tasks that fall broadly within the category of executive function.”

• AssumptionRests on an assumption: The bilingual and monolingual groups in the reviewed between-groups studies are equivalent on relevant background variables.

In older adults, bilinguals showed greater fractional anisotropy than monolinguals in corpus callosum tracts extending into the superior and inferior longitudinal fasciculi.

“The first of these was conducted by Luk et al. (2011) with older adults (70 years old) and found higher fractional anisotropy (FA) in bilinguals than monolingual in tracts across the corpus callosum and extending to the superior and inferior longitudinal fasciculi.”

• cites Luk et al. (2011)Not checked yet

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Alladi et al. (2013) replicated the 4.5-year delay in dementia symptoms initially reported by Bialystok et al. (2007).

“A study by Alladi et al. (2013) conducted in India that included all levels of socioeconomic circumstances and education replicated the 4.5 year delay in symptoms of dementia initially reported by Bialystok et al. (2007).”

• cites Alladi et al. (2013)Not checked yet

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• cites Bialystok et al. (2007)Not checked yet

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• AssumptionRests on an assumption: Age at first awareness or formal diagnosis of dementia is a valid indicator of dementia onset or protection.

Cognitive decline with aging and dementia can be modulated by stimulating experiences, a concept known as cognitive reserve.

“It has long been known that cognitive decline with aging and dementia can be modulated by stimulating experiences, a concept known as cognitive reserve (Stern, 2002).”

• cites Stern, 2002Not checked yet

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Most studies found that during nonverbal executive function tasks, bilinguals recruited networks or regions overlapping with those used in language processing.

“Second, most of the studies found that in performing nonverbal executive function tasks, bilinguals recruited networks or regions that overlapped with those used in language processing.”

In older adults, bilinguals showed lower fractional anisotropy than monolinguals in the inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, fornix, and several corpus callosum portions.

“Gold, Johnson, and Powell (2013b) tested monolingual and bilingual healthy older adults (~65 years old) and found lower FA in the bilinguals in the inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, the fornix, and multiple portions of the corpus callosum, precisely the tracts in which bilinguals had shown higher FA in other studies.”

• cites Gold, Johnson, and Powell (2013b)Not checked yet

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Bilingual experience has broad effects on brain structure, including areas far from cognitive control centers.

“Although not surprising, the results confirm that there are pervasive effects of bilingual experience on brain structure, even in areas well removed from centers involved in cognitive control.”

• cites Ressel et al. (2012)Not checked yet

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In older adults, anterior temporal pole grey matter volume declines with age only among monolinguals, not bilinguals.

“the grey matter volume of this region was significantly negatively correlated with age for monolinguals but not for bilinguals; in other words, there was a decline in grey matter density with age only for the monolinguals.”

• cites Olsen et al. (2015)Not checked yet

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Overall, the evidence indicates that bilinguals have more white matter structure.

“but the evidence clearly indicates increased white matter structure in bilinguals.”

A mismatch between brain structure and cognitive performance is the hallmark of cognitive reserve.

“This dissociation between brain structure and cognitive level is the signature of cognitive reserve.”

• AssumptionRests on an assumption: Differences in brain structure and function between monolinguals and bilinguals reflect the causal effect of bilingual experience rather than pre-existing differences.

Facilitation and interference effects of the non-target language on target-language processing make language inhibition unlikely.

“Research showing widespread facilitation and interference effects of the non-target language on processing in the target language were found for such tasks as picture naming (e.g., Costa et al., 2000) and lexical decision (Bijeljac-Babic, Biardeau, & Grainger, 1995; Duyck et al., 2007), making language inhibition unlikely.”

• cites Costa et al., 2000Not checked yet

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• cites Bijeljac-Babic, Biardeau, & Grainger, 1995Not checked yet

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• cites Duyck et al., 2007Not checked yet

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Converging evidence from child development, bilingual language processing, and adult executive function supported inhibition as central to bilingualism's cognitive effect.

“Thus, converging evidence from cognitive development in childhood, language processing in bilinguals, and executive function in adults supported the interpretation that inhibition was central to understanding the effect of bilingualism on cognition.”

Cognitive change from bilingualism is evident before productive language is established.

“Cognitive change is evident before productive language is established.”

Miyake et al. reported low intercorrelations in their original study.

“Miyake and colleagues (2000) reported in their original study that these intercorrelations were low, so it would be surprising if they became robust when applied to research on bilingualism.”

• cites Miyake and colleagues (2000)Not checked yet

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Recent empirical evidence and theorizing have cast doubt on all three sources of evidence for the inhibition interpretation.

“The accumulation of empirical evidence and recent theorizing has cast doubt on all three sources of evidence outlined above for the inhibition interpretation.”

The assumption that inhibition was the primary mechanism appears inaccurate.

“but the assumption that inhibition was the primary mechanism seems inaccurate.”

There is little correlation across various executive function tasks.

“Finally, as Paap and colleagues frequently noted (e.g., Paap & Greenberg, 2013), there was little correlation across various executive function tasks.”

• cites Paap & Greenberg, 2013Not checked yet

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Bilingual children are more advanced than monolinguals in separating word and meaning.

“it became clear that it was precisely this separation of word and meaning that was more advanced in bilingual children (review in Bialystok, 2001).”

• cites Bialystok, 2001Not checked yet

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P600 amplitude is strongly affected by syntactic violations, with larger violations producing larger P600.

“The P600 amplitude is heavily influenced by syntactic violations, with greater violations leading to enhanced P600 amplitudes (Friederici, Pfeifer, & Hahne, 1993).”

• cites Friederici, Pfeifer, & Hahne, 1993Not checked yet

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In Schweizer et al. (2012), brain atrophy was significantly greater in the medial temporal region, particularly hippocampus, for bilinguals than monolinguals despite comparable behavioral measures.

“However, an analysis of brain atrophy showed significantly more deterioration in the medial temporal region, particularly hippocampus, for the bilinguals than the monolinguals, in spite of comparable behavioral measures.”

• cites Schweizer et al. (2012)Not checked yet

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In adults, ERP showed a smaller P600 for bilinguals on grammatical but silly sentences.

“A similar pattern was later found with adults where the measure was not accuracy, for which everyone was at ceiling, but ERP showing a smaller P600 for bilinguals in the grammatical but silly sentences (Moreno, Bialystok, Wodniecka, & Alain, 2010).”

• cites Moreno, Bialystok, Wodniecka, & Alain, 2010Not checked yet

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The inhibition model provides a poor fit to the patterns of results from bilingualism research.

“Overall, the inhibition model provides a poor fit to the patterns of results obtained from research on bilingualism.”

Cognitive reserve from bilingualism should contribute to post-stroke recovery.

“but the cognitive reserve imparted by bilingualism should contribute to post-stroke recovery.”

• AssumptionRests on an assumption: Bilingualism is a stimulating experience capable of increasing cognitive reserve.

Recent work on the Miyake model eliminated inhibition entirely as a source of unique variance.

“More importantly, recent work on this model has eliminated inhibition entirely as a source of unique variance (Miyake & Friedman, 2012).”

• cites Miyake & Friedman, 2012Not checked yet

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Studies with infants and toddlers found significant differences in how monolingual and bilingual children performed nonverbal conflict tasks.

“Yet, studies with children in the first year of life (Kovacs & Mehler, 2009a) and pre-school toddlers (Bialystok et al., 2010a) both found significant differences in the way in which monolingual and bilingual children performed nonverbal conflict tasks.”

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• cites Bialystok et al., 2010aNot checked yet

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A smaller P600 is appropriate for grammatically correct sentences.

“Since the sentences were in fact grammatically correct, a smaller P600 is appropriate.”

There is at least deactivation of the non-target language that reduces access.

“At the very least, there is a deactivation of the non-target language that reduces access (see for example, Linck, Kroll, & Sunderman, 2009), but the assumption that inhibition was the primary mechanism seems inaccurate.”

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Simple executive-control tasks such as flanker were often performed equivalently by monolingual and bilingual young adults.

“Simple tasks, such as the flanker task, that are generally acknowledged to involve executive control were often performed equivalently by monolingual and bilingual young adults.”

Incidence studies should not be expected to show bilingualism's protective effects.

“For this reason, we should not expect incidence studies to reveal protective effects of bilingualism.”

Adult research did not conform to predictions from the Miyake-based framework in three crucial aspects.

“Third, the research with adults did not conform to the predictions from the explanatory framework based on the Miyake model in three crucial aspects.”

With few exceptions, incidence studies have found no significant effects of bilingualism on the likelihood of dementia.

“A small number of incidence studies has investigated the role of bilingualism in defraying the likelihood of dementia but with few exceptions (e.g., Wilson et al., 2015), no significant effects have been found (Crane et al., 2009, 2010; Hack et al., 2012; Ljungberg, Hansson, Adolfsson, & Nilsson, 2016; Sanders et al., 2012; Zahodne, Schofield, Farrell, Stern, & Manly, 2014).”

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• cites Crane et al., 2009, 2010; Hack et al., 2012; Ljungberg, Hansson, Adolfsson, & Nilsson, 2016; Sanders et al., 2012; Zahodne, Schofield, Farrell, Stern, & Manly, 2014Not checked yet

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Most studies reporting group differences on inhibition tasks found them equally in congruent and incongruent trials.

“However, the majority of the studies that reported group differences on these tasks found them equally in both trial types (Hilchey & Klein, 2011), again challenging inhibition as a likely explanation.”

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Bilingual environments or experience accelerate the development and maintenance of attention.

“Something about bilingual environments or bilingual experience accelerates the development and maintenance of attention.”

Dose-related effects of bilingualism have been found in the literature.

“would have difficulty accounting for the dose-related effects found in the literature (e.g., Bogulski, Rakoczy, Goodman & Bialystok, 2015).”

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Monitoring of attention for conflict detection is compatible with behavioral and brain evidence from bilingualism.

“Monitoring of attention, specifically for the purpose of conflict detection, therefore, is compatible with behavioral and brain evidence from bilingualism research.”

Bilingual participants with ADHD showed significant deficits compared to other groups.

“In both studies, bilingual participants with ADHD showed significant deficits compared to the other groups, suggesting that an attention disorder not only prevents bilingualism from boosting performance but possibly also adds to the burden of the disorder (note however there were no monolinguals in the Mor et al., 2015 study).”

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• cites Mor et al., 2015Not checked yet

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Infants in bilingual environments show better control over simple visual attention than infants in monolingual environments.

“In the first year of life, infants in bilingual environments demonstrate better control over simple visual attention than infants in monolingual environments.”

Adult Italian-Venetian bidialectics did not differ from monolingual Italian speakers.

“but studies with adults reported no difference between Italian-Venetian bidialectics and monolingual Italian speakers (Scaltritti et al., 2015)”

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The results suggest an underlying commonality between attention processes and processes affected by bilingualism.

“These results suggest some underlying commonality between processes involved in attention and processes affected by bilingualism.”

Abutalebi et al. found greater grey matter density changes in inferior parietal lobule for bilingual older adults who spoke similar languages than for those who spoke unrelated languages.

“Abutalebi et al. (2015) investigated increases in grey matter density in the inferior parietal lobule in bilingual older adults and reported greater changes for bilinguals who spoke similar languages (Cantonese and Mandarin) than for those who spoke unrelated languages (Cantonese and English).”

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Recent studies support the Adaptive Control Hypothesis ideas.

“A few recent studies have provided support for these ideas (Hartanto & Yang, 2016; Yang, Hartanto, & Yang, 2016; Verreyt, Woumans, Vandelanotte, Szmalec, & Duyck, 2015), but final judgment on this model awaits further research.”

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• cites Yang, Hartanto, & Yang, 2016Not checked yet

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• cites Verreyt, Woumans, Vandelanotte, Szmalec, & Duyck, 2015Not checked yet

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Engel de Abreu et al. found that low-SES bilingual 8-year-olds outperformed low-SES monolinguals.

“For example, Engel de Abreu et al. (2012) reported a study with 8-year-olds in which both monolingual and bilingual children were from very low socioeconomic backgrounds and again, bilingual children outperformed monolinguals on this task.”

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Bilingualism is interpreted as an adaptation of cognitive and neural systems used in linguistic and non-linguistic activities, not as transfer.

“Instead, the interpretation is that bilingualism involves an adaptation in which cognitive and brain systems used in both linguistic and non-linguistic activities are modified as a consequence of being involved in those activities.”

Calibration of effect size to degree of bilingualism is consistent with experience-related plasticity.

“The calibration of the size of effect to the degree of bilingualism is consistent with experience-related plasticity.”

These features make working memory capacity compatible with lifespan evidence for bilingualism-dependent plasticity.

“These two features make working memory capacity a construct that is compatible with the evidence found across the lifespan for bilingualism-dependent plasticity.”

Intense working memory capacity training, especially with complex tasks, improved near-transfer or moderate-transfer memory task performance.

“Harrison et al. (2013), for example, showed that intense training in working memory capacity, especially through the use of complex tasks rather than simple training tasks, improved performance on tasks described as near-transfer or moderate-transfer memory tasks.”

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The three interactional contexts place different demands on brain and cognitive systems by requiring different degrees and types of language switching.

“These interactional contexts – single language, dual language, and dense code-switching – place different demands on brain and cognitive systems by requiring different degrees and types of language switching.”

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No amount of working memory training increased fluid intelligence scores.

“Their measure of far transfer was an assessment of fluid intelligence, but in spite of being correlated (Engle, Laughlin, Tuholski, & Conway, 1999), no amount of training led to increased scores on fluid intelligence tests.”

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Participants who were more bilingual outperformed less bilingual participants on behavioral and brain outcomes.

“In all cases, participants who were more bilingual outperformed those who were less bilingual on both behavioral and brain outcomes.”

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• cites Sorge et al., in pressNot checked yet

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• cites Goral et al., Spiro, 2015Not checked yet

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Bidialectic children who spoke Cypriot Greek and standard Greek outperformed monolingual Greek-speaking children.

“bidialectic children who spoke Cypriot Greek and standard Greek outperformed monolingual Greek-speaking children (Antoniou et al., 2016)”

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Research examining bilingualism and SES simultaneously found independent effects for both.

“Those studies examined performance within a specific socioeconomic range, but research that has simultaneously examined both bilingualism and socioecomonic status has found independent effects for both (Calvo & Bialystok, 2014; Krizman, Skoe, & Kraus, 2016.”

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• cites Krizman, Skoe, & Kraus, 2016Not checked yet

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If the groups compared are not truly monolingual and bilingual, the comparison will yield noise or null findings.

“so comparisons between groups that are not in fact monolingual and bilingual will produce noise or null results (see discussion in Bialystok, in press).”

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Some tasks do not engage the processes that bilingualism is expected to influence.

“Similarly, not all tasks recruit processes that are expected to be impacted by bilingualism”

Models controlling for extraneous variables concluded that enhanced performance was related to adult bilingual experience.

“Models that controlled for a variety of extraneous variables all led to the conclusion that the enhanced performance was related to their adult bilingual experience.”

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When monolingual-bilingual comparisons yield no difference, the null outcome is often treated as a negative result.

“First, studies that have failed to find differences between monolingual and bilingual groups have instead found no differences, that is, null results, but are interpreted as negative results.”

Language training studies with pretest/posttest designs show post-training improvement on executive function tasks in trained children and adults but not controls.

“One method is through training studies: language training studies using pretest/posttest designs have shown post training improvement on executive function tasks for children (Janus, Lee, Moreno, & Bialystok, 2016), and adults (Bak et al., 2016; Sullivan et al., 2014) in the trained group but not in the control group.”

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Random or quasi-random assignment to training groups and equivalent pre-training performance allow post-training results to be interpreted causally.

“The use of random or quasi-random assignment to training groups and demonstration of equivalent performance across groups prior to training allows post-training results to be interpreted causally.”

That task has no feature likely to tap processes influenced by bilingualism.

“There is nothing in this task that can be expected to capture aspects of processing affected by bilingualism.”

Korean-English bilingual children outperformed both Korean monolinguals and US monolinguals on the flanker task.

“In a study by Yang and Yang (2016) using the flanker task, monolingual children in Korea attained higher accuracy than monolingual children in the US. Nonetheless, the Korean-English bilinguals outperformed both these groups, so whatever the effect of culture it did not replace the effect of bilingualism.”

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Experience does not modify brain or cognitive systems in a simple, one-dimensional way.

“However, the relation between the experience and the consequent modification of brain or cognitive systems is not simple and it is not unidimensional.”

• AssumptionRests on an assumption: Experience can affect cognitive outcomes and brain structure/function throughout the lifespan.

Bilingualism effects in countries where bilingualism is not linked to immigration are equivalent in nature and degree to effects in countries where bilinguals are more likely immigrants.

“More broadly, effects of bilingualism found in countries where bilingualism is not associated with immigration, such as India (Alladi et al., 2013) and Spain (Costa et al., 2008) are equivalent in nature and degree to effects found in countries where bilinguals are more likely to be immigrants.”

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How SES alters cognitive ability is less well understood than the fact that SES effects exist.

“Details of the mechanism by which SES modifies cognitive ability are less clear than is the evidence for their effects.”

SES has well-documented effects on cognitive and brain outcomes, including executive function development.

“There are well-documented example of the effects of SES on cognitive and brain outcomes, including executive function development (Noble, McCandliss, & Farah, 2007)”

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Bilingualism alters how language is processed.

“It is perhaps not surprising that bilingualism changes the way language processing is carried out”

• AssumptionRests on an assumption: Experience can affect cognitive outcomes and brain structure/function throughout the lifespan.

Bilingualism is not a categorical variable.

“As noted in Section 3.3, bilingualism is not a categorical variable (Luk & Bialystok, 2013)”

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Those who became actively bilingual after age 11 had intelligence scores significantly higher than predicted by their childhood results.

“The dramatic finding was that those who became actively bilingual during their lives, after age 11, produced intelligence scores that were significantly higher than those predicted by their childhood results.”

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Some studies of bilingualism's possible effects on brain and behavior have not found significant results.

“Finally, not all studies investigating the potential consequences of bilingualism on brain and behavior have produced significant findings, a point that has received considerable attention.”

More and more studies find no monolingual-bilingual difference on tasks where none should be expected.

“Increasingly, studies are reported showing no differences between monolingual and bilingual participants on tasks for which there is no reason to expect any.”

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Adult cognitive performance on executive function, nonverbal intelligence, and decision-making tasks is linked to socioeconomic status.

“Socioeconomic factors have also been related to cognitive level as measured by executive function, nonverbal intelligence, and decision making in adulthood (Mani, Mullainathan, Shafir, & Zhao, 2013).”

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High and low SES groups seem to differ crucially in attentional control.

“as in research on bilingualism, attentional control appears to be a crucial underlying difference between high and low SES groups (Stevens, Lauinger, & Neville, 2009).”

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Bilingualism also modifies nonverbal cognitive processing.

“it is certainly less expected that it also changes the way that nonverbal cognitive processing is conducted.”

• AssumptionRests on an assumption: Experience can affect cognitive outcomes and brain structure/function throughout the lifespan.

In a 60-year longitudinal study, monolinguals' intelligence at age 11 predicted intelligence at age 72.

“For those who remained monolingual, their intelligence results at age 11 predicted their intelligence results at age 72, an outcome reflecting the reliability of intelligence tests.”

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Pooled data showed monolingual children and adults scoring significantly higher than bilinguals on receptive vocabulary.

“The results showed that the distribution of scores were normal for both language groups but that monolinguals had significantly higher vocabulary scores than bilinguals for in both children (Bialystok, Luk, Peets, & Yang, 2010b) and adults (Bialystok & Luk, 2012).”

• cites Bialystok, Luk, Peets, & Yang, 2010bNot checked yet

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• cites Bialystok & Luk, 2012Not checked yet

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Studies drawn from the overlapping part of the distributions do not overturn the overall bilingual advantage pattern.

“Specific studies that come from the overlapping portion of the curves do not refute the pattern.”

The taxi-driver reorganization was too broad and intricate to be accounted for by one factor or one result.

“Put another way, the reorganization was more extensive and more complex than could be explained by a single factor or a single outcome.”

Not knowing exactly how SES influences cognitive development has not weakened the research or conclusions about SES effects.

“Yet, the absence of a precise mechanism by which SES affects cognitive development has not undermined the research and conclusions regarding the effects of SES.”

Children who had been in immersion programs longer and were more bilingual performed better on executive function tasks, over and above other factors.

“Children who had been in the programs longer and were more bilingual performed better on these tasks, over and above all other factors.”

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Across studies, bilinguals tend to perform better than monolinguals on certain cognitive tasks.

“Similarly, on average, studies show that bilinguals outperform monolinguals on some cognitive tasks.”