Expectancy effects are a widespread phenomenon, and they come with a lasting influence on cognitive operations, from basic stimulus processing to higher cognitive functions. Their impact is often profound and behaviorally significant, as evidenced by an enormous body of literature investigating the characteristics and possible processes underlying expectancy effects. The literature on this topic spans diverse fields, from clinical psychology to cognitive neuroscience, and from social psychology to behavioral biology. We present an emerging perspective on these diverse phenomena and show how this perspective stimulates new toeholds for investigation, provides insight in underlying mechanisms, improves awareness of methodological confounds, and can lead to a deeper understanding of the effects of expectations on a broad spectrum of cognitive processes.
