Table 6.

Means and standard deviations (in parentheses) of group mean parameters with the PVL-Delta model.

PVL Delta parameters	HC	A	H
Learning rate (A)	0.037 (0.019)	0.035 (0.018)	0.172 (0.080)
Reward sensitivity (α)	0.382 (0.126)	0.283 (0.116)	0.475 (0.123)
Response sensitivity (c)	1.285 (0.204)	1.292 (0.181)	0.947 (0.147)
Loss aversion (λ)a	0.650 (0.240)	0.376 (0.220)	0.060 (0.055)

HC, healthy controls; A, amphetamine; H, heroin.

^aHC > H.