Table 1.

List of symbols used in the decision-making models implemented in ChaRTr.

Parameter	Description
x(t)	State of the decision variable at time t.
Δt	Time step of the decision variable.
z, sz	Starting state of the decision variable (i.e., x(0) = z), and decision-to-decision variability in starting state. sz is the range of a uniform distribution with mean (midpoint) z.
vi, sv	Rate at which the decision variable accumulates decision-relevant information (drift rate, v) in condition i, and decision-to-decision variability in drift rate. sv is the standard deviation of a normal distribution with mean vi.
γ(t)	Urgency signal that dynamically modulates the decision variable as a function of t. Can take different functional forms in different models.
aupper, alower	Upper and lower response boundaries that terminate the decision process.
aupper(t), alower(t)	Upper and lower response boundaries that vary as a function of t.
Ter, st	Time required for stimulus encoding and motor preparation/execution (non-decision time), and decision-to-decision variability in non-decision time. st is the range of a uniform distribution with mean (midpoint) Ter.
s	Within-decision variability in the diffusion process. Represents the standard deviation of a normal distribution. By convention, set to a fixed value to satisfy a scaling property of the model.
E(t)	Momentary sensory evidence at time t.
b, sb	Intercept and variability of the intercept in urgency based models with linear urgency signals.
$\mathcal{N}(0,1)$	Normal distribution with zero mean and unit variance.
$\mathcal{U}\left(l_1,l_2\right)$	Uniform distribution over the interval l1 and l2.