ASA 125th Meeting Ottawa 1993 May

4aPP1. Comparison of adaptive procedures for obtaining psychophysical thresholds using computer simulation.

Monica L. Hawley

H. Steven Colburn

Dept. of Biomed. Eng., Boston Univ., 44 Cummington St., Boston, MA 02215

In order to compare the efficacy and efficiency of various adaptive psychophysical procedures, a program that simulates these procedures has been developed and used to compare several adaptive methods for three experiments: binaural detection, interaural intensity discrimination, and interaural time discrimination. The simulation program takes as input a psychometric function, which specifies the probability of a correct response for any value of the adapting variable. A threshold is generated by choosing the next value of the variable according to the rules of the procedure being simulated, including the rules for stopping and calculating the threshold estimate. The software generates distributions of thresholds and statistical analyses are performed, such as bias and variance of the obtained distribution. The program has been applied to psychometric functions appropriate for normal-hearing and hearing-impaired listeners for each of the three experiments noted above, and has compared a number of adaptive procedures including the Transformed Up-Down (such as 2-down-1-up), PEST, BUDTIF, and Weighted Up-Down methods. [Work supported by NIDCD and Dept. of Education.]