Drift-Diffusion Model

Drift rate v = 0.3

Boundary a = 0.8

Noise σ = 0.5

Start bias z = 0.0

Non-decision t_nd = 0.1s

Show N = 8 paths

DDM:
dX = v·dt + σ·dW
Decide when X = ±a

Accuracy: —%
Mean RT: — ms
Fast errors: —

SPRT = sequential probability
ratio test — optimal for
2-alternative decisions.

Speed-accuracy tradeoff:
lower boundary → faster
but less accurate.