“It takes a village to conduct research”: Understanding brain differences in monolinguals and bilinguals with differing reading directions

(Photos provided by Madeline Wiseman)

“I think it is fascinating that this body of work exists and reveals that there may be differences in how our brain hemispheres collaborate depending on our language background. The fact that knowing more than one language can have an influence on the way we perceive the world around us and the way our brains function is astounding to me.” ~Madeline Wiseman

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*In the following article, TS refers to The Synapse and MW refers to Madeline Wiseman;

TS: Could you briefly introduce yourself, your supervisor, the topic of your thesis, and the field it contributes to?

MW: My name is Madeline Wiseman (she/her) and I have recently graduated from the Honours psychology program with a specialization in neuroscience (BSc). My honours project was supervised by Dr. Daniel Voyer and Dr. Veronica Whitford.

Our project investigated language group differences in laterality and numerosity effects. Briefly put, “numerosity effects” describe how numbers are perceived, and “laterality” describes how the two hemispheres of the brain dominate different functions. For example, the left hemisphere of the brain dominates certain functions like language and arithmetic, whereas the right hemisphere dominates functions like navigation and recognizing emotions. Some literature has shown that bilinguals show less laterality compared to monolinguals, meaning that each hemisphere is less specific to these functions.

Specifically, we studied lateralization using a greyscale task. The greyscale task involves two rectangles presented together with one above the other. Each rectangle is coloured in a grey gradient that darkens either from right-to-left or left-to-right. Participants are asked to indicate which rectangle appears darker to them. This task is used to assess laterality, and English monolingual participants typically select the rectangle with the dark end of the gradient on the left, which indicates a right hemisphere bias.

In our task, the rectangles also contained a list of numbers in increasing order (e.g., 1, 2, 8, 9). This served to test the “SNARC effect” in English monolinguals, French-English bilinguals, and bi/multilinguals with a first language of either Arabic, Farsi, Hebrew, or Urdu. The SNARC effect (‘Spatial-Numerical Association of Response Codes’) is a numerosity effect where individuals with a left-to-right reading direction, like English and French, mentally list numbers on a number line in ascending order from left-to-right, with small numbers being associated with the left side of the body and large numbers associated with the right side of the body. Some research shows that individuals with a right-to-left reading direction, like Arabic and Hebrew show the reverse SNARC effect. These biases are associated with laterality.

This work contributes to the field of cognitive psychology in the areas of brain lateralization and language. Our project may help address some contradictions in the literature regarding performance on the greyscale task while considering factors such as the SNARC effect, language background - like monolingualism and bilingualism - and first-language reading directions (e.g. left-to-right vs. right-to-left reading directions).

TS: What was the inspiration for your study, your research question, and the main results?

MW: The initial stage of this project was a collaboration between me and Dr. Voyer. He had presented a few ideas for research projects, and I was interested in the topic of laterality. We had discussed the greyscale task and a concept called the SNARC effect, which I had no previous knowledge about.

This topic seemed fascinating, but I wanted to take it a step further. Apart from perception, I was also interested in studying language and I knew that Dr. Voyer had a history of studying individual differences in perception, so I felt this was the perfect opportunity to mix our interests. I did some digging and discovered that there were many discrepancies in the literature surrounding laterality and language differences between monolinguals and bilinguals.

Furthermore, I found only one study that used a greyscale task to assess differences in laterality between monolinguals and bilinguals, and it had a few gaps. I brought it to Dr. Voyer’s attention, and we decided to combine language group differences, laterality, and the SNARC effect into one study by using the greyscale task with numerical overlays. Dr. Whitford, who specializes in language research, was soon added to the project. With the combined expertise of Dr. Voyer and Dr. Whitford, my project was set in motion.

Once we had a topic, we composed the following research questions:

1) Does lateralization on a greyscale task differ between English monolinguals (left-to-right reading), French-English bilinguals (left-to-right reading), and bi/multilinguals with a first language of either Arabic, Farsi, Hebrew, or Urdu (right-to-left reading)?; and

2) Does the SNARC effect differ between these three language groups?

The results for my honours thesis were preliminary in nature due to time constraints, but data collection is ongoing. There were thirty-one participants in total, all of which were undergraduate students at UNB. Ten participants were English monolinguals, thirteen were French-English bilinguals, and eight were bi/multilinguals with a first language of Arabic or Urdu. The preliminary results revealed no significant language group differences in laterality on the greyscale task, nor a significant SNARC effect for all three groups. Interestingly the bi/multilingual right-to-left reading group approached a reverse laterality effect, but these results did not reach significance.

TS: Could you provide a brief summary of the methods used in this study?

MW: We recruited participants from SONA and from poster advertisements posted on campus and public settings. Once participants signed up, we asked them to complete a series of pre-screening measures to determine their eligibility.

First, the participants were asked to complete an online questionnaire that included questions on demographics (e.g., age, sex at birth), language background, and whether they were right-handed or left-handed. Next, the participants completed subtests of the Wechsler Individual Achievement Test (WIAT-II) over Microsoft Teams to assess word reading fluency and accuracy. All participants completed the English version of the WIAT-II, and French-English bilinguals were given the French version as well. After participants completed these measures and were deemed eligible, they were invited to our lab to complete a computerized greyscale task.

TS: Are there any future studies that will be conducted based on your method or results?

MW: Our study is still ongoing, with data collection expected to continue into the fall semester.

Depending on the final results we receive, Dr. Voyer or Dr. Whitford may be interested in continuing research with similar methods, or, once we publish, I am sure there will be some researchers who may be interested in replicating this work.

I currently have no intention of pursuing further research on this topic since I will be conducting a different body of research for my graduate studies. That is not to say I will never return to this topic, but it is currently not my main area of focus.

TS: What would you consider the most intriguing part of your research?

MW: I think it is fascinating that this body of work exists and reveals that there may be differences in how our brain hemispheres collaborate depending on our language background. The fact that knowing more than one language can have an influence on the way we perceive the world around us and the way our brains function is astounding to me.

I also think that, if this research shows differing laterality between bilinguals/multilinguals and monolinguals, more people may feel drawn to learning new languages. This would be beneficial on both an individual level and on a societal level as language diversity continues to increase in North America.

Lastly, further evidence from this area of research may have implications for brain damage remediation, which is really exciting! If bilingual patients exhibit reduced laterality between the hemispheres, they may be able to recover certain functions - such as language - faster than their monolingual counterparts.

TS: Is there anything else you wish to share about the research experience?

MW: I thoroughly enjoyed this experience of conducting research for the first time. I have learned a lot during this process, and I am grateful for the guidance I had from my supervisors. I am especially grateful to the research assistants in Dr. Whitford’s lab for their help with data collection. Without them, I would not have been able to gather the amount of data I had for my thesis, and we certainly would not be able to continue collecting data into next semester. I am very appreciative of all of their help! We hear the saying “it takes a village to raise a child”, but the saying should also go “It takes a village to conduct research”! It truly is the collaboration in a research team that makes this all possible. I sincerely thank everyone involved in this project! Ψ

Created for The Synapse by Incé Husain.