Numerical ratings of subjective perceptions were acquired at the beginning and end of each block; the two scores were averaged to give a single score for each block. Subjects responded to 7 questions using a computerized visual analog scale (Figure 2), as implemented in past studies (Morzorati et al., 2002; Ramchandani et al., 2002; Wetherill et al., 2012). Six of the 7 questions included a term followed by several dictionary-derived synonyms intended to provide subjects with a common understanding. These questions were designed to encompass a broad range of possible subjective effects of alcohol: Tired (and its synonyms) reflected negative sedation; Relaxed (and its synonyms): positive sedation; Anxious: negative stimulation; Stimulated: positive stimulation; Enjoying: liking of the alcohol experience; Intoxication: feeling a drug effect. Estimated Number of Drinks was included as an intuitive metric reflecting the subject’s prior experience with alcohol.
