The performance measures included four computerized tasks and two non-computerized tasks (see Evans et al., 2000 for details). All of the performance measures described below, with the exception of the word recall task, were conducted during the experimental sessions at baseline (before dosing) and 0.5, 1, 2, 3 and 4 h after dosing. The computerized tasks consisted of a 3-min Digit Symbol Substitution Test (DSST; McLeod et al., 1982), a 5-min Divided Attention task (DAT; Miller et al., 1988), and an immediate and delayed Digit Recall task (Roache and Griffiths, 1987). A balance task measured motor coordination (Evans et al., 1990) by assessing the participant's ability to stand upright for a maximum of 30 sec on each foot with eyes closed. Lastly, a paper/pencil Word Recall and Recognition task was conducted with immediate recall at 1.5 h, delayed recall at 2.5 h and 4 h, and delayed recognition at 4 h after drug administration (Evans et al., 1998).
