Table 1.

Descriptive Statistics for Participants Who Consumed Amino-Acid Drinks Containing (T+) or Not Containing (T–) Tryptophan

Treatment group	Gender	Mean age (years)	Mean Raven’s matrices score	Mean BIS-11 score	Mean PANAS trait score
					Positive affect	Negative affect
T+	7 male, 9 female	24.44 (1.65)	55.53 (1.17)	58.00 (2.22)	34.44 (0.96)	13.94 (0.91)
T–	9 male, 7 female	23.56 (0.92)	56.63 (0.80)	62.56 (1.86)	37.00 (1.22)	14.56 (1.06)

Note: Standard errors are given in parentheses. Participants completed measures of cognitive ability (Raven’s Standard Progressive Matrices Sets A, B, C, D, & E; Raven, 1996), impulsivity (Barratt Impulsiveness Scale, or BIS-11; Patton, Stanford, & Barratt, 1995), and positive and negative state affect (Positive and Negative Affect Schedule, or PANAS; Watson, Clark, & Tellegen, 1988).