Language athletes: Dual-language code-switchers exhibit inhibitory control advantages

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This questionnaire is used as an entry screen. It allows participants to choose the language in which they prefer to complete the consent form and questionnaires (English or French).

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This task measures domain-general cognitive flexibility. We adopted a common variant for feature shifting task, wherein participants were required to indicate either the shape (rectangle, square) or the colour (blue, green) of a geometric figure, according to a preceding cue. Shifting takes place when two consecutive trials are cued by distinct features.

The colour-shape shifting task in the current project is composed of three blocks. The first two blocks are single-cue blocks. In the ‘shape’ block, there are 32 rectangle trials and 32 square trials (each split evenly in colour). In the ‘colour’ block, there are 32 blue trials and 32 green trials (each split evenly in shape). The final fixed block is a mixed-cue section: it is composed of 64 repeated- cue trials (50% colour → colour, 50% shape → shape) and 64 switched-cue trials (50% colour → shape, 50% shape → colour).

There are five practice trials before each single-cue block and ten practice trials before the mixed-cue block. Before each block, participants are given the opportunity to take a break. One ‘throwaway’ trial is included after every break in order to avoid excessive loss of data. To keep the experiment interactive, participants see their ‘score’ (proportion of correct responses) at the end of the task. In total, each participant see 256 experimental targets (half in the single-cue blocks and half in the mixed-cue block). These trials were pseudo-randomized within blocks into two different orders.

In this task, a single trial adopts the following procedure: A fixation cross is first presented for 250 ms. For single-cue trials, the target figure (outlined in black, over a white screen) appears immediately after the fixation. For mixed- cue trials, the feature cue (black font in uppercase letters: SHAPE/COLOUR) is presented for 500 ms before the target figure appeared. Participants are instructed to press ‘f’ for a blue or square target, and ‘j’ for a green or rectangular target. An image of a keyboard depicting these responses remains on the screen during the practice trials; this mnemonic disappears during the experimental trials. The task flow does not proceed until a keyboard response was selected. Participants receive 200 ms feedback after each individual trial.

The task lasts approximately 8-12 minutes.

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Materials (lists/images) available at:
https://osf.io/rscnf/?view_only=c8ec9953e42547b8924e2c15f9f6a53c

Adapted from a Gorilla sample
https://app.gorilla.sc/admin/task/17050/editor

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This questionnaire provides the consent form in English. Participants may not continue with the experimental flow until informed consent is provided.

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This questionnaire provides the consent form in French. Participants may not continue with the experimental flow until informed consent is provided.

Creative Commons Attribution (CC BY)

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This questionnaire is used as an end screen for the study (for participants who chose to complete the forms in English). It allows participants to provide their email if they'd like to receive the final results of the study. It also allows participants to give feedback about the experiment.

Creative Commons Attribution (CC BY)

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This questionnaire is used as an end screen for the study (for participants who chose to complete the forms in French). It allows participants to provide their email if they'd like to receive the final results of the study. It also allows participants to give feedback about the experiment.

Creative Commons Attribution (CC BY)

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This task measures domain-general inhibitory control. We utilized an adapted version of the original Eriksen Flanker task wherein an arrow is flanked by four horizontally-aligned symbols (two on each side). The participant is asked to identify the direction (left or right) of the center arrow. In congruent trials, flanker arrows face same direction as the central target (left:<-- <-- <-- <-- <--, right:--> --> --> --> -->). In incongruent trials, flanker arrows face the opposite direction of the target (left: --> --> <-- --> --> , right: <-- <-- --> <-- <--). Finally, in neutral trials, the central target is flanked by simple dashes (left: — — <-- — —, right: — — --> — —).

The Flanker task in the current project includes 100 congruent, 100 incongruent, and 100 neutral trials (split evenly among left-facing and right-facing targets and fully randomized for each participant). There are ten practice trials at the beginning of the task. To keep the experiment interactive, participants see their ‘score’ (proportion of correct responses) at the end of the practice trials and at the end of the task. Participants are given the option to take a break every 50 trials. Three ‘throwaway’ trials are included after every break in order to avoid excessive loss of data.

In this task, a single trial adopts the following procedure: A fixation cross is first presented for 250 ms. Next, the target and its flankers appear in black font over a white screen. Participants are instructed to press ‘f’ (the left-most keyboard option) with their left hand when the target-arrow faces left, and to press ‘j’ (the right-most keyboard option) with their right hand when the target faces right. The task flow does not proceed until a keyboard response is selected. Participants receive feedback for 200 ms after each individual trial. A green thumbs-up appears in the case of correct responses, and a red thumbs-down appears in the case of an incorrect response.

The task takes approximately 5-7 minutes to complete.

Creative Commons Attribution (CC BY)

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Materials (lists/images) available at:
https://osf.io/x9nad/?view_only=e12ba0ea64c243729045d18313865762

Adapted from a Gorilla sample
https://app.gorilla.sc/admin/task/16739/editor

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This experiment tree displays the experimental flow of the study reported in the pre-print paper "Language athletes: Dual-language code-switchers exhibit inhibitory control advantages" (L. Gosselin & L. Sabourin, University of Ottawa).

Participants completed all four online tasks after the background questionnaires, and in counterbalanced order. A break screen appeared between each task. Participants could thus progress through the experiment at their own pace; there was no set time limit to complete the study.

All inter-task and intra-task counterbalancing is presented in the experiment tree.

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This questionnaire is used as a screen that prompts the participants to take a break between each task.

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This questionnaire prompts participants to provide various demographic and language background information. It includes questions adapted from three sources:

• The ERPLing Lab's Language Background Questionnaire (see Sabourin, Leclerc, Lapierre, Burkholder & Brien, 2016)
• The Bilingual Switching Questionnaire (BSwQ; see Rodriguez-Fornells, Kramer, Lorenzo-Seva, Festman & Münte, 2012).
• The Language mixing questionnaire (see Byers-Heinlein, 2013)

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ERPLing Language Background Questionnaire
https://cla-acl.artsci.utoronto.ca/wp-content/uploads/actes-2016/Sabourin_etal_CLA2016_proceedings.pdf

Bilingual Switching Questionnaire
https://doi.org/10.3389/fpsyg.2011.00388

Language Mixing Questionnaire
https://doi.org/10.3389/fpsyg.2011.00388

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This questionnaire prompts participants to provide various demographic and language background information. It includes questions adapted from three sources:

• The ERPLing Lab's Language Background Questionnaire (see Sabourin, Leclerc, Lapierre, Burkholder & Brien, 2016)
• The Bilingual Switching Questionnaire (BSwQ; see Rodriguez-Fornells, Kramer, Lorenzo-Seva, Festman & Münte, 2012).
• The Language mixing questionnaire (see Byers-Heinlein, 2013)

Creative Commons Attribution (CC BY)

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ERPLing Language Background Questionnaire
https://cla-acl.artsci.utoronto.ca/wp-content/uploads/actes-2016/Sabourin_etal_CLA2016_proceedings.pdf

Bilingual Switching Questionnaire
https://doi.org/10.3389/fpsyg.2011.00388

Language Mixing Questionnaire
https://doi.org/10.3389/fpsyg.2011.00388

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This task is used to measure language-specific cognitive flexibility. In this paradigm, participants are required to indicate whether a string is a real word or a non-word, according to a preceding language cue (i.e., French or English). Shifting in mental sets takes place when two consecutive trials are in different languages.

The lexical decision task in the current project included 50 non-cognate French-English translations pairs, 50 English pseudo-words (e.g., drack, wetch, chortle, harets, jayl...) and 50 French pseudo-words (e.g., rique, larpe, tousue, malaud, stin...). The real English words (and their French translations), as well as the English pseudo-words, were taken from Sabourin, Brien & Burkholder (2014). The French pseudo-words were selected from the French Lexicon Project (see Ferrand et al., 2010).

The lexical decision task is composed of three blocks. The first two blocks are single- language blocks. In each of the unilingual French and unilingual English blocks, there are 49 real-words trials and 49 non-words. The order of the single-language blocks is counterbalanced across lists. The final fixed block is a bilingual block: it is composed of 98 repeated-cue trials (50% French → French, 50% English → English, counterbalanced for real word/nonword status) and 98 switched-cue trials (50% French → English, 50% English → French, counterbalanced for real word/nonword status).

There are five practice trials before each single-cue block and ten practice trials before the mixed-cue block. Participants are given the option to take a break after every block and half-way through the bilingual block. One ‘throwaway’ trial was included after every break in order to avoid excessive loss of data. To keep the experiment interactive, participants see their ‘score’ (proportion of correct responses) at the end of the task. In total, each participant see 392 experimental targets (half in the single-cue blocks and half in the mixed-cue block). These trials are pseudo-randomized within blocks into two different orders.

In this task, a single trial adopts the following procedure: A fixation cross is first presented for 250 ms. For single-cue trials, the target word (uppercase black font over a white screen) appears immediately after the fixation. For mixed-cue trials, the feature cue (black font in lowercase letters: English/français) is presented for 500 ms before the target word appears. In one list, participants are instructed to press ‘f’ for a real-word and ‘j’ for a pseudo-word; the keys are reversed for the second list. The task is participant-controlled: it does not proceed until a keyboard response is selected. Finally, participants receive 200 ms feedback after each individual trial.

The task takes approximately 10-15 minutes to complete.

Creative Commons Attribution (CC BY)

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Materials (lists/stimuli) available at:
https://osf.io/pxybm/?view_only=70dc3757c8dd47be95c022356334b59c

Stimuli derived from Sabourin et al. (2014):
https://doi.org/10.1017/S1366728913000643

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This task is used to measure language-specific inhibitory control. During this task, participants see chroma-related words (e.g., red, blue, green) and non-chroma words (e.g., house, door, book) in different coloured fonts. They are asked to identify the colour of the font and ignore the meaning of the text. Similar to the Flanker task, the Stroop paradigm is composed of three critical trial types. In congruent trials, the colour of the font conforms to the meaning of the word (i.e., ‘RED’ written in red). In incongruent trials, the colour of the font conflicts with the meaning of the word (i.e., ‘RED’ written in green). Finally, neutral trials are baseline or control items, wherein a non-chroma word is presented in a colour- font (i.e., ‘BOOK’ written in red).

The Stroop task in the current project utilized French-English bilingual stimuli (see Sabourin & Vīnerte, 2015, 2020). The chroma words (BLACK/NOIR, GREEN/VERT, RED/ROUGE, WHITE/BLANC, YELLOW/JAUNE) and non-chroma words (BOOK/LIVRE, DOOR/PORTE, HOUSE/MAISON, SNOW/NEIGE, TREE/ARBRE) are non-cognates in these languages.

The task is composed of three blocks. The first two blocks are single-language blocks (i.e., only English stimuli, or only French stimuli), each including 25 congruent trials, 25 incongruent trials and 25 neutral trials (150 single-language trials total). The order of the single-language blocks is counterbalanced across lists. The final fixed block is bilingual: it is composed of 50 congruent trials, 50 incongruent trials and 50 neutral trials, with each condition split evenly in French and English. The experiment begins with twenty-five practice trials. To keep the experiment interactive, participants see their ‘score’ (proportion of correct responses) at the end of the practice trials and at the end of the task. Participants are given the option to take a break every 100 trials. Five ‘throwaway’ trials str included after every break in order to avoid excessive loss of data. In total, each participant sees 300 experimental targets, individually randomized within blocks.

In this task, a single trial adopts the following procedure: A fixation cross is first presented for 250 ms. Next, the target (outlined in black) appears in uppercase letters over a white screen. Participants are instructed to place both hands on the keyboard and to press ‘d’ for a target in red font, ‘f’ for yellow font, ‘j’ for white font, ‘k’ for black font, or the spacebar for green font. An image of a keyboard depicting these responses remains on the screen during the practice trials; this mnemonic disappears during the experimental trials. The task is participant-controlled: it does not proceed until a keyboard response is selected. Finally, participants receive 200 ms feedback after each individual trial. A green thumbs-up appears in the case of correct responses, and a red thumbs-down appears in the case of an incorrect response.

The task takes approximately 7-10 minutes to complete.

Creative Commons Attribution (CC BY)

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Materials (lists/images) available at:
https://osf.io/5gfvh/?view_only=cfca1575df7c45e48e6a241939f6dc6d

Stimuli derived from Sabourin & Vīnerte (2015):
https://doi.org/10.1017/S1366728914000704

Adapted from a Gorilla sample:
https://app.gorilla.sc/admin/task/16735/editor