Question

How does conducting a double-blind study attempt to remedy the experimenter expectancy effect?

Answer 1

In double-blind experiments, neither the subjects nor the experimenters know which subjects belong to the control group nor the test group.

In what is called the observer-expectancy effect, the experimenter may subtly communicate their expectations for the outcome of the study to the participants, causing them to alter their behavior to conform to those expectations.

When the experimenter is ignorant of which subjects belong to the the test group, he will not know what the expected result should be and hence he will not accidentally disclose the true expected outcome to the subjects.