Foreign Language Effects on Judgment and Decision Making

Introduction

The language we use can influence not only how we communicate, but also how we think and make decisions. Psychologists, linguists, and neuroscientists have explored for decades how language might shape thought. Much of this work examines how syntactic and semantic elements of different languages impact language users' cognition, such as their perception of concepts of time and space (Boroditsky, 2001). A research program has emerged that investigates the impact of language use on thought from a different perspective. Instead of examining what elements of language could impact thought, or what differences between languages could alter users' perceptions, this research focuses on how using a foreign language, as opposed to a native tongue, influences thinking and decision-making. The implicit assumption in the field is that if language users are presented with a choice, as long as they fully understand the language, whether it is native or foreign should be immaterial to the process or the outcome. Research demonstrates, however, that the nativeness of the language systematically affects the way people make decisions. This finding has societal impact because millions of people worldwide use a language other than their native tongue to make decisions every day. These decisions range from what to eat or buy, to consequential choices such as whether to get a flu shot or undergo certain medical treatments. In the following sections, we review how the use of a foreign language influences decision-making under uncertainty, moral judgments, and ethical behavior. We also discuss applied domains such as food preferences and health-related choices, as well as the mechanisms proposed to explain these effects.

Foreign Language Effects on Decisions Under Uncertainty

Research in decision theory has shown that the way information is presented can influence people’s decisions, especially under conditions of uncertainty (Tversky & Kahneman, 1981). For example, in a positive frame (e.g., 70% survival), people tend to prefer the sure gain (saving a certain number of people) over a gamble that could save more or none. In contrast, when the same outcome is presented in a negative frame (e.g., 30% mortality), people become more risk-seeking, preferring the gamble over a certain but smaller loss. This decision-making bias is known as the framing effect (Kahneman & Tversky, 1984). It demonstrates that people’s risk attitudes are not a function of the content of the choice. Instead, these attitudes flip depending on how information is framed.

One explanation for why framing effects occur is loss aversion, which refers to the tendency for people to weigh prospective losses more heavily than equivalent gains (Tversky & Kahneman, 1974). This asymmetry in evaluation means that outcomes that are framed in terms of losses can lead to different decisions than logically equivalent outcomes that are framed in terms of gains. The negative affective impact of losses tends to be stronger (e.g., 30% will die) than the positive affective impact of equivalent gains (e.g., 70% will survive). This stronger affective response increases risk-seeking behavior in the negatively framed condition, as people are motivated to avoid the perceived loss.

The emotional intensity of information could influence how people process it and use it in their decision-making (Loewenstein et al., 2001). Greater emotional intensity can make people more prone to decision-making biases, partly because it increases reliance on intuitive rather than deliberative information processing (Kahneman, 2011). It has been theorized that using a foreign language reduces the emotional intensity of information [for an overview, see (Pavlenko, 2012)]. Supporting evidence for this idea comes from applied psycholinguistic research. For example, emotionally charged words such as "death" or "cancer" elicit weaker physiological responses, such as reduced skin conductance, when presented in a foreign language learned formally after the age of seven, compared to a native language (Caldwell-Harris, 2015). Such weaker physiological responses are typically interpreted as indicating reduced affective reactions. Reduced affective processing of information, in turn, can make people less susceptible to decision biases, such as framing effects. Therefore, using a foreign language may help counteract these biases and promote less affect-based choices (Keysar et al., 2012). An alternative account could suggest that using a foreign language requires more mental effort, which could increase cognitive load. This, in turn, may lead to greater reliance on intuitive processing and thereby exacerbate certain decision biases that stem from intuition (e.g., Geipel et al., 2025).

One of the pioneering studies on how the use of a foreign language influences decision-making under uncertainty investigated differences in framing effects and loss aversion when decisions are made in a native versus a proficient foreign language (Keysar et al., 2012). Across three studies, participants were tested either in their native language (e.g., English, Japanese, Korean) or in a proficient foreign language they had learned through formal instruction (e.g., French, English). The results demonstrated that when using a foreign language, the typical framing effect disappeared or was substantially reduced. This phenomenon, known as the foreign language effect, has been replicated in subsequent research with different foreign and native languages, suggesting that cultural or language type differences are unlikely to drive the effect [see (Costa, Foucart, Arnon, et al., 2014; Winskel et al., 2016)].

Beyond framing effects, research has investigated how the use of a foreign language influences other decision-making domains under uncertainty, such as probability judgments about future events (Oganian et al., 2019), risk perception of hazards (Hadjichristidis et al., 2015), and bidding behavior in economic markets (Fu et al., 2025). Across these domains, findings similarly suggest that using a foreign language dampens affective reactions and reduces reliance on intuitive processing, which can in turn influence decision-making. For example, evidence shows that hazards such as nuclear power or nanotechnology elicited less negative affect when presented in a foreign language (English) rather than in a native language (Italian). This resulted in higher judgments of benefit and lower judgments of risk in the foreign language (Hadjichristidis et al., 2015). Other work has shown that foreign language use (English or French) reduces optimism bias, the tendency to overestimate the probability of positive events (e.g., owning a house) and underestimate the probability of negative ones (e.g., witnessing an accident) among native speakers of German (Oganian et al., 2019). Foreign language use has also been shown to attenuate another decision bias under uncertainty, the hot hand fallacy in games of chance. This fallacy is the tendency of people to increase risk-taking after experiencing a win even though the series of gambles are independent (Ayton & Fischer, 2004; Gilovich et al., 1985). In one study, native speakers of Chinese were more cautious and slower to gamble when positive outcomes were presented in their foreign language (English) compared with their native language (Gao et al., 2015). Neural evidence from event-related potentials suggested that positive outcomes elicited weaker responses in the foreign language, supporting the idea that reduced affective responses in a foreign language can attenuate decision biases (Gao et al., 2015).

Foreign Language Effects on Moral Judgments and Ethics

Foreign language effects on judgment and decision-making also extend to other domains, such as moral judgments (Cipolletti et al., 2016; Costa, Foucart, Hayakawa, et al., 2014; Geipel et al., 2015a, 2016). People often face moral dilemmas that involve a conflict between two moral frameworks: deontology, which emphasizes adherence to rules or duties (e.g., “do not kill”), and utilitarianism, which focuses on the outcomes of actions and the goal of maximizing the greater good (e.g., lying to protect someone’s life). For example, such a dilemma arises when facing a choice between saving the lives of five people by killing one person. Doing so would violate an ethical rule but would maximize the greater good. According to one dual-process model (Greene et al., 2004), moral judgments that favor deontology-type judgments are typically more intuitive and affect-driven, whereas utilitarian-type judgments tend to rely on more controlled and deliberative cognitive processes. When considering moral dilemmas that are presented in a foreign language rather than a native language, people tend to make judgments that align more closely with utilitarian principles (Cipolletti et al., 2016; Costa, Foucart, Hayakawa, et al., 2014; Geipel et al., 2015b; Kyriakou & Mavrou, 2023, 2025). However, follow-up studies have shown that using a foreign language can reduce both deontological and utilitarian judgments (Białek et al., 2019; Hayakawa et al., 2017; Kirova et al., 2023; Muda et al., 2018), with a greater reduction observed in deontological responses. Collectively, these findings support the idea that making moral judgments in a foreign language may reduce people’s sensitivity to social and moral norms, as well as diminish the affective impact evoked by processing moral dilemmas in one’s native language (Geipel et al., 2015b).

Research has also examined everyday social norm violations (e.g., jumping the queue), morally questionable actions (e.g., cleaning the toilet with a national flag), or serious crimes (e.g., homicide committed for selfish motives) (Geipel et al., 2015a; Hu & Navarrete, 2025; Woumans et al., 2020). These studies have found that when such actions are described in a proficient foreign language, people tend to judge them as less morally wrong or less severe than when they are presented in their native language. In line with this research, studies have demonstrated that norm-violating actions, such as telling a black lie, are judged as more acceptable, whereas norm-adhering actions, such as telling a white lie, are judged as less acceptable, when evaluated in a foreign language (Hu & Navarrete, 2025). Together, these findings provide more fine-grained evidence that foreign language use influences people’s sensitivity to social norms.

Studies have also investigated how language use influences unethical behavior (Bereby-Meyer et al., 2020). For example, in a well-established cheating paradigm (Fischbacher & Föllmi-Heusi, 2013; Shalvi et al., 2011), participants are asked to roll a die privately multiple times and then report the highest number they rolled. The reported number determines their bonus payment, with higher numbers yielding higher rewards. This setup creates an incentive to cheat by reporting higher numbers than actually rolled, and it has been shown to reliably evoke unethical behavior (Fischbacher & Föllmi-Heusi, 2013). Studies have found that when this cheating-incentivized task is conducted in a foreign language (English or Spanish) rather than a native language (Hebrew, Korean, Spanish, and English), participants tend to cheat less (Bereby-Meyer et al., 2020). However, other research did not observe a consistent language effect on cheating behavior in a sample of native Chinese and German speakers proficient in English as a foreign language (Alempaki et al., 2021). This study found that participants judged cheating as less appropriate when described in native Chinese or German compared to foreign English. Follow-up research suggests that the effect of foreign language on cheating depends on how the behavior is perceived (Gai & Puntoni, 2021). When cheating is seen as a threat to one’s social image, such as reflecting negatively on how others might view the person, using a foreign language increases cheating. In contrast, when cheating is perceived as reflecting positively on the person, such as being clever or resourceful, using a foreign language tends to reduce cheating (Gai & Puntoni, 2021).

Taken together, this research demonstrates that moral judgments about dilemmas, transgressions, crimes, and social norms, as well as ethical behavior, can be influenced by using a foreign language. These foreign language effects are consistent with the idea that foreign language reduces affective resonance and social norm sensitivity, thereby affecting how people make moral judgments and engage in ethical behavior.

Foreign Language Effects on Applied Decision-Making

The foreign language effect also extends to applied domains with real-world consequences. These include food choices, sustainable consumption, and health communication. In consumer behavior, research has shown that participants were more likely to choose healthy over unhealthy food when the food was labeled in a foreign language (English) rather than in their native language (German) (Klesse et al., 2015). One possible explanation is that unhealthy foods, such as chocolate-based desserts, are often perceived as more indulgent and hedonic. Using a foreign language may reduce this affective appeal, consistent with the broader finding that foreign language use attenuates emotional responses (Caldwell-Harris, 2015), thereby making it easier for people to resist temptation and choose healthier alternatives. Extending this pattern, research has shown that food products that are typically perceived as aversive when described in one’s native language, such as recycled wastewater from the toilet, lab-grown meat, or insect-based foods, elicit weaker feelings of disgust when described in a foreign (English or German) rather than a native language (German, Dutch, Italian). This reduction in reported feelings of disgust in a foreign language was associated with increased willingness to consume these aversive food products (Geipel et al., 2018). A similar effect has been observed beyond food. In the domain of fashion, sustainable products described in a foreign language (English) rather than a native language (German) were chosen more often (Saile et al., 2025). Pro-environmental choices often involve a higher subjective experience of effort, for example, when they require going against social norms that favor buying the newest styles (Osbaldiston & Schott, 2012). Using a foreign language may lessen this perceived effort, which in turn can increase the likelihood of selecting environmentally friendly products (Saile et al., 2025). Overall, these findings suggest that using a foreign language can increase willingness to choose healthier foods and more environmentally friendly products by reducing indulgent appeal, dampening disgust, and lessening the perceived effort of sustainable choices.

Studies have also begun testing how the language of medical information can influence people’s evaluations and behavioral intentions. Consistent with the idea that foreign language use attenuates emotional reactions, descriptions of medical conditions such as flu, chickenpox, or breast cancer presented in a foreign language (English) were perceived as less severe than the same medical conditions presented in the native language (Chinese) (Hayakawa et al., 2022). Participants also rated these conditions as easier to treat, less physically painful, and less distressing. Similarly, disease symptoms and treatment side effects described in a foreign language (English) rather than in the native language (Chinese) were judged less negatively (Hayakawa et al., 2021). The use of a foreign language has also been shown to influence how much control people feel in response to public health advice. For example, reading instructions to avoid spreading COVID-19, such as Keep a distance of at least 1.5 metres from others, in a foreign language (English) rather than in the native tongue (German) increased participants' sense of control (Saile et al., 2022). This heightened sense of control, in turn, was positively associated with greater behavioral intentions to follow the advice. A study conducted in Hong Kong at the time of the COVID-19 vaccine introduction similarly found that presenting vaccine information in English, rather than in participants’ native Chinese, increased intentions to get vaccinated (Geipel et al., 2022; see also Schmid & Roehr-Brackin, 2024). In this case, the effect was explained by greater trust when the vaccine information was presented in English than in Chinese.

Taken together, research on applied decision-making suggests that using a foreign language can influence decisions through different mechanisms. First, it attenuates affect by reducing the indulgent appeal of unhealthy foods, dampening disgust towards unconventional foods, and lessening the perceived severity or negativity of medical conditions. Second, it reduces the subjective effort involved in making pro-environmental decisions. Third, it affects health behavior by increasing perceptions of control and trust. In these affect-laden decision contexts, using a foreign language has been found to promote healthier and more sustainable choices as well as greater compliance with medical advice.

Programmatic and Contextual Constraints

Methodological Considerations

One novel aspect of research on the foreign language effect is that it demonstrates the causal impact of language on aspects of thought. Typical studies of language and thought confound language with culture, personality, or geographic location, which can themselves influence how people think. These confounds make it difficult to determine whether a difference found between, for example, Spanish and English speakers, is due to the language itself or to culture or location. In contrast, studies on the foreign language effect typically test the same native speakers and randomly assign them to perform a task in either their native tongue or a foreign language. Any differences can therefore be attributed to the language used. Even with such random assignment, there is always a possibility that the language effect arises not from its nativeness but because the language itself differs in grammar or primes its associated culture, which in turn might cause the effect. Studies of the foreign language effect address this potential methodological problem by crossing the languages when possible. For example, in a study on moral dilemmas (Costa, Foucart, Hayakawa, et al., 2014), half the participants were native speakers of Spanish using English as a foreign language, and the other half were native speakers of English using Spanish as a foreign language. This design showed that the effect was not a function of the language itself but of its nativeness.

Contextual Constraints

In addition to methodological considerations, research has identified contextual factors that influence the strength of foreign language effects on decision-making. In general, these effects tend to be stronger in situations that involve affective reactions and greater reliance on language. For example, when people have to weigh potential gains and losses in the context of a health crisis, or make judgments about morally questionable actions, using a foreign language can change their responses (Costa et al., 2014a, 2014b; Geipel et al., 2015a, 2016; Keysar et al., 2012). By contrast, in contexts that are emotionally neutral or rely mainly on numerical or logical reasoning, such as solving abstract problems or interpreting statistical information, foreign language effects tend to be absent (Hayakawa et al., 2018; Milczarski et al., 2024; Muda et al., 2020; Vives et al., 2018; Winskel et al., 2016). They are, for example, often absent in financial decision-making paradigms in which participants are presented only with a number and a pie chart indicating probabilities (e.g., "keep 20 for sure" vs. gamble (De Martino et al., 2006);), rather than with linguistically rich descriptions such as hypothetical scenario-driven tasks (Dylman & Champoux-Larsson, 2020; Hayakawa et al., 2018; Winskel et al., 2016). This suggests that its influence is most pronounced in situations where both emotion and language are central.

Conclusion

This chapter has reviewed research showing that the use of a foreign language can systematically influence judgment and decision-making across diverse domains. Broadly speaking, in contexts where intuitive, affect-laden responses drive biases, such as framing effects, risk perception, or food choices, using a proficient foreign language reduces emotional reactivity, leading to less biased and better outcomes. In contexts where emotional and normative sensitivity support better judgments, such as moral transgressions, social norm violations, crimes, or ethical behavior, foreign language use can reduce decision quality and produce poorer outcomes. In other contexts, particularly those that are linguistically poor or rely primarily on logical or numerical reasoning, foreign language use has little or no effect. These findings, then, demonstrate that the impact of language on decision-making is context dependent.

Language is not merely a tool for conveying content; it also influences how people process information, make judgments, and ultimately think and behave.