Utility of a dynamic termination criterion in the ZEST adaptive threshold method

Vision Res. 2003 Jan;43(2):165-70. doi: 10.1016/s0042-6989(02)00396-6.


Bayesian adaptive threshold procedures may be run for a fixed number of trials, or may be stopped when the calculated confidence interval for the threshold reaches a selected limit (a dynamic termination criterion). This study used Monte-Carlo simulations to determine whether the confidence interval is a useful predictor of errors in the estimated threshold. No difference was found between the distribution of errors in a fixed trial procedure versus a dynamically terminated procedure of the same average number of trials. In addition, the width of the confidence interval failed to usefully predict observer variability arising from a shallow psychometric function slope or increased false positive response probabilities. This study suggests that dynamic termination criteria are of little use in Bayesian adaptive threshold procedures.

MeSH terms

  • Adaptation, Physiological / physiology*
  • Bayes Theorem
  • Contrast Sensitivity / physiology
  • Humans
  • Monte Carlo Method
  • Psychometrics
  • Psychophysics
  • Sensory Thresholds / physiology*
  • Visual Perception / physiology*