Abstract
Bilinguals make decisions differently across languages, likely due to reduced affect in the foreign language, a phenomenon linked to the Foreign Language Effect (FLE). While the FLE suggests that decision-making in a second language can be more rational or emotionally detached, less is known about how bilingual individuals actively choose between languages in strategically loaded contexts. This thesis explores both directions of this relationship: how communicative intentions shape language choice, and how different language contexts influences bilingual decision-making.Across three empirical studies, we examine the dynamic interplay between language, emotion, and decision-making in Chinese—English bilinguals. The first two studies focus on strategic language use (SLU), the idea that bilinguals choose their language (either L1 or L2) to achieve a particular communicative goal (i.e., score maximisation). The third study reverses the direction of inquiry by investigating how language context affects the neurophysiological processes underlying decision-making. All three studies employed lie-incentivised coin game paradigm in which bilingual participants registered their decisions to either bet or drop after knowing the outcome of a draw (coin/no coin). When they drew a coin, they had to tell the truth and declare having one (i.e., bet). When they drew a blank, they were free to bet (i.e., pretend they had a coin), or tell the truth and drop (i.e., not bet). After each trial, participants then received feedback, and were explicitly instructed to engage in strategic deception as needed to maximise their score.
In Study 1, we set out to examine whether Chinese—English bilinguals use their native (Chinese) and foreign language (English) strategically. Participants were invited to freely choose either L1 or the L2 to announce the outcome of each draw. Results revealed a clear preference for using Chinese to tell the truth, suggesting a strategic alignment between emotional honesty and native language use. Such use of the native language was conceptually equivalent to using English to lie. Additionally, they switched one language to the other more frequently following truthful statements, predominantly towards Chinese.
In Study 2, we expanded these findings by examining how verbal feedback—in different languages (Chinese or English) and of varying valence (positive or negative), modulates language choice and risk-taking behaviour. Participants showed a preference for choosing Chinese following positive feedback delivered in Chinese, whereas feedback given in English had minimal impact on subsequent language choices. They were also more likely to switch languages after negative feedback compared to positive feedback.
In Study 3, we examined the neurophysiological underpinnings of decision-making by measuring electroencephalography activity as bilingual participants performed the coin-drawing task in separate language blocks. Although behavioural results were largely comparable across language contexts, EEG analyses uncovered a distinct temporal dissociation: information integration during decision-making was delayed in the foreign language context, whereas neural markers of risk evaluation emerged earlier. This suggests that decision-related processes operate differently across languages at the neurophysiological level, despite similar outward behaviour.
Taken together, these findings suggest that bilinguals not only tend to process information and make decisions differently depending on the language context in which they find themselves, with decision-making sometimes disrupted by second language exposure, but also actively navigate their dual language systems to optimise outcomes under uncertainty. We conclude that decision-making is covertly affected differently by two languages of bilinguals, which may have broader societal implications in domains such as diplomacy, immigration, and cross-cultural negotiation.
| Date of Award | 12 Jan 2025 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Guillaume Thierry (Supervisor) & Paul Rauwolf (Supervisor) |