<Tr> <Td> <Ul> <Li> Psychology portal </Li> </Ul> </Td> </Tr> <Ul> <Li> Psychology portal </Li> </Ul> <P> The observer - expectancy effect (also called the experimenter - expectancy effect, expectancy bias, observer effect, or experimenter effect) is a form of reactivity in which a researcher's cognitive bias causes them to subconsciously influence the participants of an experiment . Confirmation bias can lead to the experimenter interpreting results incorrectly because of the tendency to look for information that conforms to their hypothesis, and overlook information that argues against it . It is a significant threat to a study's internal validity, and is therefore typically controlled using a double - blind experimental design . </P> <P> An example of the observer - expectancy effect is demonstrated in music backmasking, in which hidden verbal messages are said to be audible when a recording is played backwards . Some people expect to hear hidden messages when reversing songs, and therefore hear the messages, but to others it sounds like nothing more than random sounds . Often when a song is played backwards, a listener will fail to notice the "hidden" lyrics until they are explicitly pointed out, after which they are obvious . Other prominent examples include facilitated communication and dowsing . </P>

What is it called when the results are influenced by expectations of the researcher