A meta-analysis [7] of 175 primary literature studies of Modafinil in humans demonstrated significant improvements in executive functions (most notably attention and memory) on both simple tasks and complex tasks. However, only 24 studies employed a double blind randomized control trial study design. Ritalin, in a meta analysis of 19 randomized control trials [8], was found to demonstrate a consistent effect specific to memory, but failed to demonstrate an effect for other executive functions.