1. Bilingualism: Consequences for Mind and Brain Bialystok, Craik & Luk
Michaela Reichert
BCS 265

2. Why this paper? Languages Bilingual studies Bilingualism in the family
American Sign Language (ASL) Major
Bilingual studies
Bilingualism in the family
I’ve always loved languages and learning them  reason why I’m an ASL major
In BCS 259 we went over some bilingual studies, but there are so few studies even though there are many bilingual people
My dad is bilingual and it has always fascinated me/made me strive to become bilingual in something

3. Why Bilingualism? Very prevalent in today’s society
Context: Functional Neuroplasticity
Bilingual people make up half of the European population, and around 20% of the American pop
Want to look at a part of the community that is under-represented in research
In the context of bilingual studies, we are actually studying functional neuroplasticity  really the crux of bilingual research
- the idea that experience modifies brain structure and function and looking at how it does that

4. What’s Different about Bilingual Minds?
Negative or Positive?
Peal and Lambert study
Two major trends in recent studies
Verbal skills
Word retrieval tasks
BUT, better executive control
Is bilingualism beneficial or detrimental to language learning?
- Early on, it was thought to have negative effects, but a study by Peal and Lambert In the 60’s kind of triggered people thinking that research in this area was important and interesting
They did a study where they looked at both monolingual and bilingual children from Montreal, where they speak French and English. They did a bunch of different tests, that weren’t specified in the reading, and predicted that they would score lower on the language tasks, but similarly to monolinguals on the non-verbal spatial tasks. What they found, however, was quite surprising, as the bilingual children outperformed the monolingual children on all the task  esp. ones that required symbol manipulation and reorganization. Basically, they found that bilingual children were better at metalinguistic awareness (or the ability to solve linguistic problems based on understanding such concepts as the difference between form and meaning) and non-verbal problem solving
In the 60’s, this kind of triggered people thinking that research
Verbal skills generally weaker than monolinguals
Slower in word retrieval tasks
BUT, bilinguals have better executive control  for all ages
- in children this is very important for academic success
- is there actually evidence for this?

5. What does language processing look like for bilinguals?
Two independent language systems?
Maybe not
How do we know that there aren’t two independent language systems?
Cross language priming and lexical decision studies
Consequences for Joint Activation
competition
The original theory was that there were two independent language systems that didn’t interact, but could be tapped into
Now, there is a new theory called Dual Activation Theory, or joint activation
- the idea that there is always a measure of activation and interaction between the two languages
Evidence for joint activation:
- cross language priming studies  try to find an example
- lexical decision studies: participants decide whether a string of letters is an actual word in one of the languages
- English-Russian bilinguals get distracted by words that have shared phonology with Russian
- Thierry and Wu study  participants were accessing Chinese forms when making judgments on semantic relationships between English words
- based on N400 results
- studies have been done with cross-modal bilinguals and it shows similar results with languages such as ASL
But, bilinguals have constantly competing languages and have to choose which ones to use when, monolinguals don’t have that problem

6. So, what is inhibition? Two types
Global
Local
Shows reduced speed and fluency of lexical access
Enhanced attentional control?
Global inhibition = suppressing an entire language system (i.e., suppressing English when speaking Spanish or vice versa) affects linguistic and cognitive performance
Local inhibition = inhibition of a specific competing factor (i.e., a translation equivalent) affects only linguistic performance
Both completely necessary for bilingual fluency
Green’s ICM appears to be more in-line with these two inhibitory processes that are necessary to be fluent
Inhibition shows us results similar to the findings of studies earlier  reduced speed and fluency of lexical access for bilinguals, but here we see them begin to really argue that bilinguals have enhanced attentional control

7. What do Cognitive networks look like in Bilinguals?
Performance on Conflict Tasks
Children vs. Young Adults vs. Older Adults
Neural Correlates
Method: fMRI (reliable?)
Two primary areas:
Dorsolateral prefrontal cortex
Broca’s area
Basic Idea
Bilingual children seem to outperform other children on conflict tasks such as the Stroop Test or the Simon Test
Older adults also seem to outperform other older adults
Young adults do not seem to show these effects, why?
- Bialystok proposes that perhaps this is because they are at the developmental peak age for cognitive control
- seem to better on the more difficult tasks, but it is still very variable and sporadic  still pretty unknown
Studies to find out neural correlates often use fMRI, but as Wesley pointed out, it may not be the most reliable method due to it’s poor temporal resolution, so we should take this with a grain of salt
Two areas involved (based on first studies):
- DLPFC: dorsolateral prefrontal cortex (involved in general executive control, such as deciding which task to do or focusing on the one that you’re currently doing)
- Broca’s area and left frontal area involved in language switching task
Basic Idea of cognitive network is that distributed cortical activation that converges in the frontal regions appears to show executive control (neural) activation for bilinguals
The author’s thought that this was surprising, but it doesn’t really seem that way, after they were describing all the different ways that bilinguals demonstrated that they were better at executive control, as well as the fact that they are constantly dealing with deciding with language to speak in and when and focusing on staying on task (i.e., communicating in the correct language)

8. Brain Activation Shows frontal regions activated
Structure/function differences
Green areas indicate bilingual language switching
Red-yellow areas indicate white matter integrity in older bilingual adults as opposed to monolinguals
- remember that white matter has a much higher myelination level that allows information to be transmitted much faster
BUT fMRI only shows that these areas are included in bilingual language selection, comparison between monolinguals and bilinguals is needed in order to truly see if bilinguals have a reconfigured network
- only a handful of studies on this

9. Do bilinguals have a reconfigured network?
Only a few studies
Color-shape switching task
Monolinguals vs. Bilinguals
Right IFG vs. left IFG
Luk study
Any definitive conclusions?
Some studies about white and grey matter
There have only be a few studies that have been done contrasting the neural correlates of monolinguals and bilinguals
- Color-shape switching task
- bivalent stimulus (red circle) and a cue (color or shape) were shown to the participants and they had to indicate the dimension
- monolinguals showed increased right inferior frontal gyrus, while bilinguals showed increased left IFG activation patterns
- right IFG associated with larger switch costs basically meaning that it’s harder to ignore the irrelevant information (monolingual) and left IFG associated with smaller switch costs (bilingual)
- left IFG associated with speech production; overall more activation in bilinguals  could mean it’s an overlapping brain area for bilingual language switching and non-linguistic cognitive control
Luk study
- flanker task (i.e., figure out which direction the red chevron was facing while ignoring the black ones)
- congruent vs. incongruent trials looked different for bilinguals  show an altered network, but not for “no go” motor responses
- consistent with earlier studies of children and adults
- and showed a brain behavior correlation when suppressing info from the flankers
In terms of whether or not the anatomy has actually reconfigured itself, the results are pretty inconclusive. The article states that they’d need to look beyond fMRI to actually study the anatomical structures of these brain networks to see if there is change
- but a few studies have looked into the anatomical structure. It appears that there may be a higher density of grey matter in the left inferior parietal regions  associates more strongly with fluency of second language
- more white matter in bilingual older adults  which is primarily responsible for higher executive control

10. Bilingual Advantage?
Seems to produce enhanced frontal-posterior attentional control mechanisms
How do we know?
Maybe babies can shed some light on this
If not inhibition control, then what?
Maybe a combination of things
Bilingual infants don’t lose phonetic discrimination across all languages, and don’t confuse the two languages when they’re learning to speak them
- AND they can even discriminate just by seeing a video with a language change (i.e., someone is talking in french, and then switches to English or vice versa, but the video is silent)
- even bilingual babies that don’t share the language do this (so, Spanish-Catalan bilingual babies can also notice a change)
- so, it seems that babies have increased perceptual awareness, but it doesn’t look like they’re doing it via any of the inhibition models
- then what are they doing?
Maybe they’re just better at cognitive monitoring, or picking out irrelevant information than monolinguals
Could also be interference suppression  suppressing the other language or (for non-verbal studies) the irrelevant information
“Instead, the ongoing experience of monitoring two languages, in conjunction with the need to monitor context, speaker and other environmental clues while inhibiting attention to the currently unused but active language modifies how the mind and brain engage in ordinary conversation for bilinguals.”

11. Does Bilingualism give you an advantage against age-related cognitive decline?
Based on idea of enhanced cognitive control, could postpone onset of dementia symptoms
Cognitive reserve
Three questions:
Reliability
Validity
Casuality
Cognitive reserve = idea that engagement in stimulating physical/mental activity can act to maintain cognitive functioning in healthy aging and postpone the onset of symptoms for those suffering from dementia
- really interesting idea to me, because my grandmother is bilingual and has dementia
- does it actually slow this process down?
a study by Bialystok, Craik and Freedman showed that on average, monolinguals showed symptoms around 75 yo, while bilinguals showed symptoms around 78 yo
Reliability – appears to be some empirical support
Validity – socioeconomic status, occupational status, education level  all contributing factors
Casuality – idea that people have “good brains” that are resisting dementia and simultaneously are good at “picking up languages”
- unlikely scenario, because bilinguals don’t learn language because they’re good, but rather because they’re forced to
- but they still show resistance to dementia relative to monolinguals

12. Concluding Remarks Peal and Lambert’s idea of “mental flexibility”
Neuroplasticity
BUT, what does research now have to say about bilingual “advantages”?
This idea of “mental flexibility” isn’t very well defined by the paper, but it seems to encompass the overarching statement of this paper
The authors put it perfectly when they say (pg. 247)
“Bilinguals do sometimes have an advantage in inhibition, but they also have an advantage in selection; bilinguals do sometimes have an advantage in switching, but they also have an advantage in sustaining attention; and bilinguals do sometimes have an advantage in working memory, but they also have an advantage in representation and retrieval.”

13. Are there actually advantages?
“file drawer effect”
De Bruin study on publication bias
What is actually going on, then?
Are there advantages?
It could just be that people are only publishing the data that is showing a bilingual advantage, even though studies have been done that show that the advantage is either only somewhat helpful, or that there isn’t one at all
- those with results favoring bilingual advantage were more likely to be published
- negative results are kept in the “file drawer”
Begs the question as to whether or not there are advantages, both physically and neurally or if there aren’t
Huge question that needs to be answered  is there anything different AND better happening in bilingual brains?

14. Lingering Questions Are bilingual brains really any different?
What about multilingual brains?
What do cross-modal studies show? Are bilingual signers different than bilingual speakers?
What about people that become fluent later in life (after infancy and critical period)? Do their brains look different?
By multilingual, I mean like tri-lingual
This paper talked about the neural benefits of bilingualism, but it left a lot of questions open