Table 3.

Performance on the Information Sampling Task in the four groups [mean (SD)]

	Drug-naive	Ecstasy	Ex-ecstasy	Cannabis
Fixed reward
P(Correct)	0.85 (0.10)	0.84 (0.09)	0.86 (0.08)	0.78 (0.07)
Boxes	14.8 (4.6)	15.4 (4.4)	15.7 (4.1)	11.8 (3.8)
Errors	1.0 (1.1)	1.3 (1.1)	1.1 (1.0)	1.8 (1.2)
Reward conflict
P(Correct)	0.74 (0.06)	0.73 (0.06)	0.77 (0.07)	0.70 (0.07)
Boxes	8.9 (2.5)	9.3 (3.4)	11.2 (3.6)	8.2 (3.8)
Errors	2.5 (1.2)	2.3 (1.3)	2.2 (1.4)	2.1 (1.2)