For people with a language or cognitive impairment, the difference between "know" and "think" can be the difference between understanding and not understanding a sentence.

Zimmerer, V.C., Varley, R.A., Deamer, F., Hinzen, W. (2019). Factive and counterfactive interpretation of embedded clauses in aphasia and its relationship with lexical syntactic and general cognitive capacities. Journal of Neurolinguistics, 49, 29-44.

Çokal, D., Zimmerer, V., Varley, R., Watson, S., Hinzen W. (2019). Comprehension of embedded clauses in schizophrenia with and without formal thought disorder. The Journal of Nervous and Mental Disease, 207(5), 384-392.

You and your friend get ready for a day trip to the coast. You see your friend pack light clothing and sunscreen. “I know that it is sunny over there,” she says. You check the weather forecast. It is all clouds and rain. “No,” you say. “You just think that it is sunny.”

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