Does linguistic similarity matter in the foreign language effect in decision making and emotional resonance?

Abstract This study investigated the role of linguistic similarity in the foreign language effect (FLE) on decision-making and emotional resonance. Previous research has found that using a foreign language (L2) leads to reduced emotionality and increased rationality compared to a first language (L1). We report two experiments with different target languages: Experiment 1 investigated L1 and L2 speakers of English, and Experiment 2 investigated L1 and L2 speakers of Swedish. Participants in both experiments completed three decision-making tasks, including the Asian disease problem, a moral dilemma, and the Cognitive reflection test. The L2 speakers also reported their emotional resonance using the Reduced Emotional Resonance in LX scale (RER-LX). Results from Experiment 1 showed no significant FLE in the decision-making tasks but indicated that linguistic similarity affects emotional resonance. Experiment 2 found a classic FLE in all decision-making tasks, with participants in L2 contexts making more rational and utilitarian decisions. However, linguistic similarity did not consistently affect the magnitude of the FLE. The study highlights the complexity of the FLE and suggests that factors such as age of acquisition and immersion may influence its manifestation.