Using a foreign language reduces mental imagery.

Mental imagery plays a significant role in guiding how we feel, think, and even behave. These mental simulations are often guided by language, making it important to understand what aspects of language contribute to imagery vividness and consequently to the way we think. Here, we focus on the native-ness of language and present evidence that using a foreign language leads to less vivid mental imagery than using a native tongue. In Experiment 1, participants using a foreign language reported less vivid imagery of sensory experiences such as sight and touch than those using their native tongue. Experiment 2 provided an objective behavioral measure, showing that muted imagery reduced accuracy when judging the similarity of shapes of imagined objects. Lastly, Experiment 3 demonstrated that this reduction in mental imagery partly accounted for the previously observed foreign language effects in moral choice. Together, the findings suggest that our mental images change when using a foreign tongue, leading to downstream consequences for how we make decisions.