A new study published today in the Proceedings of the National Academy of Sciences showed that being exposed to faces or images that you associate with your home country primes you to think in your native tongue, making it more difficult than ever to speak a foreign language. Researchers from the Singapore Management University and Columbia University found that Chinese students who had recently moved to the U.S., seeing several different types of China-related visual cues measurably reduced their fluency in English. All this could eventually have some impact on the practices surrounding the teaching of second languages, providing further evidence that immersion is the most effective way for someone to gain mastery.