http://scholar.google.com/scholar?q=Is%20working%20memory%20training%20effective%3F%20A%20meta-analytic%20review
Melby isn’t the only relevant meta-analysis; you can find some more cited in my http://www.gwern.net/DNB%20meta-analysis
http://scholar.google.com/scholar?q=Is%20working%20memory%20training%20effective%3F%20A%20meta-analytic%20review
Melby isn’t the only relevant meta-analysis; you can find some more cited in my http://www.gwern.net/DNB%20meta-analysis