Deliberate and nondeliberate suggestions can influence cognitions and behaviors in surprising ways. Sometimes suggestions are helpful and improve our cognitions and behaviors, but at other times they are harmful. Suggestions can create response expectancies: the myriad ways in which we anticipate responding automatically to various situations. In this article, we discuss some of the most recent and intriguing reported effects of suggestion on cognition and behavior—effects that should make us stop and wonder, but should also make us reflect on the possibility that other well-known findings are the result of suggestion and expectation. The boundaries and underlying mechanisms of the effects of suggestion are puzzles waiting to be solved.
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