An experiment that claimed to show that meditation reduces anxiety proceeded as follows. The experimenter interviewed the subjects and rated their anxiety. The subjects were then randomly assigned to two groups. The experimenter taught one group how to meditate, and they meditated daily for a month. The other group was simply told to relax more. At the end of the month, the experimenter interviewed all the subjects again and rated their anxiety levels. The meditation group had less anxiety. This study was criticized for not being blinded. What does ‘not blinded’ mean? Group of answer choices: The experimenter who was rating the subjects knows whether they were in the meditation group or not. There is no real control group since one group was taught to meditate and the other group was told to relax more. Anxiety is hard to quantify and the rater who reviewed their anxiety level may give different ratings than other raters. The subjects in the control group did not take a placebo.
The Correct Answer and Explanation is:
Correct answer:
The experimenter who was rating the subjects knows whether they were in the meditation group or not.
Explanation:
In scientific experiments, “blinding” is a technique used to prevent bias. It ensures that the people involved in the experiment do not influence the results based on their knowledge of the treatment given. In this particular study, the lack of blinding refers to the fact that the experimenter knew which participants were in the meditation group and which were not. This knowledge could unconsciously affect how the experimenter rated the participants’ anxiety levels.
For example, if the experimenter expects meditation to reduce anxiety, they might unintentionally rate those in the meditation group more favorably, even if there is no significant difference in the participants’ actual anxiety. This is known as observer bias. When the person measuring the outcome knows the treatment status of each subject, their expectations can subtly influence the measurement, leading to skewed results.
Blinding prevents this by keeping the experimenter unaware of who received which treatment. In a single-blind study, either the subjects or the experimenters are unaware of the group assignments. In a double-blind study, both the subjects and those assessing the outcomes do not know who is in which group. This method helps ensure that any differences observed are due to the treatment itself, not to expectations or biases.
Although the other answer choices point out legitimate concerns in experimental design, they do not directly address the meaning of “not blinded.” Therefore, the best answer is the one that highlights the experimenter’s awareness of group assignments as the key flaw in the design.
