On this episode of The Big 5 Dr. Harry Clelland tells us about his work on using different types of language to communicate statistics. His work has the potential to inform medical professionals and health communicators about the best way to communicate risk to patients and the public.
To find out more about the Metascience project Harry will be working on, you can check out their website here.
In the simplest of terms, a bilingual person is someone who can communicate in at least two languages (Grosjean, 1982). Until the 1980s, it was believed that being bilingual is disadvantageous because the brain’s capacity is very limited; hence, speaking two languages would use more brain power and make it less effective. Some scientists went as far to say that children growing up in bilingual families are more likely to face learning difficulties. If you think that sounds untrue, then you are absolutely correct!
So, let’s discuss what has changed and how bilingualism is perceived nowadays. In short, rather positively. In the last 20 years, scientists have found substantial evidence for the beneficial impact of bilingualism on the human brain. Many argued that active use of two languages can improve sustained attention and executive functions such as inhibitory control. This means that a bilingual person will have, on average, better ability to focus their attention in response to a stimulus or activity. Additionally, it may be easier for a bilingual to suppress or ignore irrelevant information. This advantage observed in bilinguals is usually explained by the fact that bilinguals need to constantly suppress one language while using another, therefore they obtain some additional cognitive training.
Furthermore, brain scans demonstrated that in certain brain regions, bilinguals and monolinguals differ in activity level when they are performing exactly the same tasks. These findings clearly support the idea that using more than one language provides a person with some extracurricular brain training, which changes its activity. Naturally, contrasting opinions were voiced that didn’t fully agree with the concept of bilingual superiority in cognitive functioning. For instance, Duñabeitia and colleagues (2014) did not find any advantage amongst bilingual children compared to monolingual children on the task measuring inhibitory control.
Despite those contradictory findings, the recent review of the research in the area showed that most studies present results supporting the ‘bilingual advantage’ theory. In fact, there is a general consensus now, that speaking two languages does not constrain one’s cognitive abilities and if anything, it improves them.
All things considered, the belief that bilingualism can be beneficial for the brain is justifiable. Following this logic, researchers started exploring other ways this new knowledge could be applied. Some suggested that since bilinguals receive more cognitive stimulation throughout their lifespan, they may develop additional protection against cognitive decline. After all, growing evidence suggests that stimulating the mind can protect our thinking skills as we grow older. For instance, in a study by Martin and colleagues (2011), it was found that older people who received memory training showed better immediate and delayed verbal recall than people who didn’t.
But how exactly could bilingualism impact cognitive ageing?
Exciting new evidence suggests that being bilingual may impact some mechanisms responsible for slowing down the decline in thinking skills caused by age. One thing that scientists have observed is that the cognitive changes we see in ageing, don’t always map on to physical changes in the brain, in that some people appear to be more ‘protected’ against the effects of age. Researchers have proposed that this is due to something called Cognitive Reserve. This cognitive reserve is proposed to help some individuals cope with brain damage and age-related changes in the brain.
Crucially for our research, it is now believed that we can strengthen our cognitive reserve throughout our lifetime. For example, education, occupation and physical activity are all related improved cognitive reserve. Furthermore, as you could have already guessed, bilingualism is thought to be another contributor to the construct of the cognitive reserve. We can derive from this that people who are bilingual may develop more cognitive ‘resources’, thus mitigating the effect of ageing.
Why does this matter?
If all of the above is true, then is there really a need for further research? Well, the need certainly exists due to the constant increase in cases of dementia, a disorder caused by a serious decline of thinking abilities such as memory and problem-solving. Importantly, cognitive reserve holds out the promise of interventions that could alleviate the risk of dementia. Consequently, since bilingual seniors are thought to possess a better cognitive reserve than non-bilingual seniors, they should be more efficiently protected from developing dementia symptoms.
By 2050 the number of people diagnosed with dementia is projected to at least double! This will impact not only the patients’ families but also taxpayers in general. To prevent this disaster, we need to work and try to find effective ways to slow down cognitive ageing. Researching bilingualism evidently provides some hope for a better understanding of cognitive decline and therefore dementia, which hopefully helps reduce the effect this disease has on the population.
Can you help with our research on this topic?
With this goal in mind, our team has started investigating how bilingualism can strengthen cognitive reserve. We specifically focus on the impact of proficiency in the second language, time passed since acquiring the second language and the frequency of using the second language in day-to-day life.
To keep the sample consistent, we are recruiting people who use English as their second language and are aged 60 or above. The results of our study should provide us with some insight into the role these variables play in the cognitive reserve and we hypothesized that all factors will be positively correlated with better cognitive performance.
It is important to mention that our survey controls for other factors, which could influence cognitive reserve, such as a persons general intelligence, health, social network and activities. If you know anyone who meets our criteria, please let them know (using the link below). Every contribution is priceless and in the long run, may reveal the secrets behind delaying cognitive ageing.
We know that birds that can sing, including parrots, have distinct centres in their brain supporting vocalisations, called the “cores”. But, exclusively in parrots, around these there are outer rings, or “shells”. Surrounding this is a third region supporting movement. This is an older pathway that is shared by vertebrates. To find out more about what the unique shell system actually does, the research team analysed the expression of genes in these pathways in nine different species of parrot. They focused on ten genes that we know to be more active in the song regions of birds’ brains compared to other parts of the brain.
They found that parrots, when compared to other birds, have a complex pattern of specialised gene expression in all three parts of its brain. That means that most of the vocal learning that is specific to parrots, such as imitation, must be taking place in the shell region and the part of the brain that controls movements. This is surprising, as previous work had assumed that only the dedicated core system would be involved in vocal learning and that the shells had nothing to do with talking.
My own research has shown that it is the connections between brain regions controlling cognitive and motor skills that support language in humans.
The researchers also examined songbirds and hummingbirds and found that the shell regions were indeed unique to the parrots. However, they said future research would have to clarify the exact mechanisms involved in imitating.
That this shell system is observed in so many species of parrot – including in Keas, the most ancient species known – suggests that the vocalisation abilities evolved around 29m years ago. For comparison, that is more or less the time when humans’ ancestors are believed to have branched off from other primates.
The researchers hypothesise that this shell structure evolved after the core system for singing in birds was duplicated in the brain, with the shell centre developing new functions such as mimicking. So studying the shell structure in parrots could help us identify other mysterious duplications that could have led to certain brain functions in humans.
Only parrots, humans and certain types of songbird can mimic other species. The fact that species as different as birds and humans share this behaviour is a clear example of “convergent evolution,” in which two species independently evolve structures supporting similar behaviours.
Imitation requires significant brain power and complex, specialised processes. For example, acoustic information must be represented, its organisation decoded and finally the sound reproduced. The complex specialisation of the core, shell and motor systems in parrots support these processes for imitation, enabling these species to couple auditory information from the environment with the finely grained behaviours necessary to produce them. There is currently no evidence suggesting that parrots have any special kind of articulators for producing spoken language. Rather, their brains seem to be doing the extra work.
Interestingly, the authors also note that humans and parrots belong to another select set of animals – those that synchronise body movements to the rhythms of beats while listening to music. That is, unlike almost every other animal in the world, parrots and humans spontaneously dance (strangely enough, that group also includes elephants which have also demonstrated an ability to move along with music).
In parrots, such dancing is associated with the non-vocal motor regions surrounding the shell – which supports the possibility of a general capacity for learning regularities in the sounds they hear and coupling them with behaviour.
The study is a big step forward in our effort to understand what makes parrots so different from other birds. Indeed, the researchers themselves say they were surprised that the brain structures they discovered had gone unrecognised for so long.