Yes, but parent is arguing that the feeling could be what is affecting the test results more than any cognitive abilities or enhancements as a result of playing

Yes, but parent is arguing that the feeling could be what is affecting the test results more than any cognitive abilities or enhancements as a result of playing the game. I.e. if you "won" the Lumosity games (which normally get harder until you fail) and "lost" at Portal, is the effect the same or is it reversed? A very valid question indeed.