Unfortunately, the basketball study cited in the article had no control group. So we do not know how much of the performance improvement is attributable to the

Unfortunately, the basketball study cited in the article had no control group. So we do not know how much of the performance improvement is attributable to the placebo effect and the Hawthorne effect. Perhaps all of it? If anyone can post references to better studies I would be grateful. The basketball study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119836/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119836/