Conclusions
A moderate dose of d-amphetamine increased PLE on different scales. However, d-amphetamine does not directly affect performances on SST, but may impair SWM through its effects on PLEs that manifest during longer WM delays. In addition, moderate doses of caffeine do not affect performance on SST and DST. Overall, the present findings indicate that moderate dose of d-amphetamine and moderate doses of caffeine do not directly affect performances on DST or SST with and without delays.