Detecting concealed language knowledge via response times

In the present study, we introduce a response-time-based test that can be used to detect concealed language knowledge, for various potential applications (e.g., espionage, border control, counter-terrorism). In this test, the examinees are asked to respond to repeatedly presented items, including a real word in the language tested (suspected to be known by the examinee) and several pseudowords. A person who understands the tested language recognizes the real word and tends to have slower responses to it as compared to the pseudowords, and, thereby, can be distinguished from those who do not understand the language. This was demonstrated in a series of experiments including diverse participants tested for their native language (German, Hungarian, Polish, Russian; n = 312), for second language (English, German; n = 66), and several control groups (n = 192).