Redundant-signals race model

A model in which separate sensory channels can each trigger a response, and the first completed channel determines response time. Context invariance means that a channel's marginal completion distribution is unchanged between its single-signal and redundant-signal conditions. Independence is a separate, stronger assumption.

Under context-invariant channel distributions, $P(\min (T_A,T_V)\le t)=P(T_A\le t\mathrm{or}{T}_V\le t)\le F_A(t)+F_V(t)$ by the union bound; probability is also at most one. No independence assumption is needed. A reliable violation rejects this model with those marginals, not every possible separate-channel or decision account.