Which term describes bias arising from participants' belief they are receiving an active treatment?

Which term describes bias arising from participants' belief they are receiving an active treatment?

• A. Placebo effect
• B. Experimenter expectancy
• C. Confounding variable
• D. Descriptive statistics

Answer: (A)

The main concept is the placebo effect: when a participant believes they are receiving an active treatment, that belief can produce real improvements in symptoms or outcomes even though the treatment is inert. This happens because expectations can shape perception and even brain processing, so simply thinking you’re being helped can lead to noticeable changes. This is why it’s considered bias arising from the participant’s belief about the treatment. In trials, researchers counteract this with control groups and often a double-blind design so neither participants nor researchers know who gets the real treatment, helping ensure observed effects come from the treatment itself rather than expectations. The other options don’t fit this specific bias. Experimenter expectancy bias involves the researcher’s expectations influencing the results, not the participant’s beliefs about receiving treatment. A confounding variable is an outside factor that correlates with the treatment and the outcome, potentially distorting the apparent effect. Descriptive statistics are merely summaries of data, not a bias stemming from belief about treatment.

The main concept is the placebo effect: when a participant believes they are receiving an active treatment, that belief can produce real improvements in symptoms or outcomes even though the treatment is inert. This happens because expectations can shape perception and even brain processing, so simply thinking you’re being helped can lead to noticeable changes.

This is why it’s considered bias arising from the participant’s belief about the treatment. In trials, researchers counteract this with control groups and often a double-blind design so neither participants nor researchers know who gets the real treatment, helping ensure observed effects come from the treatment itself rather than expectations.

The other options don’t fit this specific bias. Experimenter expectancy bias involves the researcher’s expectations influencing the results, not the participant’s beliefs about receiving treatment. A confounding variable is an outside factor that correlates with the treatment and the outcome, potentially distorting the apparent effect. Descriptive statistics are merely summaries of data, not a bias stemming from belief about treatment.