Change-detection hit rates rise along an invariant cumulative Erlang-shaped curve.

Evidence

In order to compare the hit rate dynamics for different change sizes, we fitted (least-square non-linear minimization) a cumulative Erlang distribution to the data according to: where P 0 is the minimal hit-rate, P max is the maximal hit rate, t c is change time, Δ c the change size, γ the incomplete gamma function, τ the function rate, and k controls the function shape. k was kept constant across subjects and change sizes, assuming the shape of the hit rate curves is invariant, which appeared to be the case in our sample. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3291

Categorization

• QUESTION: The Erlang shape parameter k held constant across subjects and change sizes is an empirical assumption worth verifying — what theoretical mechanism (accumulator model, integration window) would predict it?