Adaptive threshold procedures: BUDTIF.

Consideration of recent psychoacoustic research reveals that, independent of the general acceptance of the theory of signal detectability, threshold methodology continues to play a major role in the acquisition of psychoacoustic data. Although adaptive methods are widely used, the newer, finite‐trial, adaptive methods are not—possibly owing to a misconception regarding the impossibility of obtaining psychometric function slopes and information other than threshold with such methods. The simplest of the finite‐trial adaptive methods, the Block Up‐and‐Down, Two‐Interval Forced‐Choice (BUDTIF) method is investigated, and an attempt is made to show the feasibility and efficiency of obtaining such information with an adaptive method. Specifically, the variability and bias of repeated thresholds obtained using human subjects with two‐, four‐. and eight‐trial block sizes and from 16 to 144 per threshold were determined. Results indicate that, for a target performance level of 75%, a block of four trials leads to...