Leonard Cobb discovered that one technique in which knots are tied in two arteries demonstrated this psychological phenomenon. Kaptchuk et al. separated this phenomenon into three components and argued that ritual causes this phenomenon. This effect is called “powerful” in the title of a 1955 paper by Henry Beecher and can be harnessed by removing masking procedures in (*) “open-label” studies. In 2023, the FDA concluded that the oral decongestant phenylephrine was no more effective than alternatives that employ this effect. Replacing the first syllable (10[1])of this word with “no” gives its inverse, which may be the cause of electromagnetic hypersensitivity. This effect may be observed through sham surgeries or prescribing sugar pills. For 10 points, name this effect in which a patient improves despite being given a useless treatment. ■END■