Threshold estimation in two-alternative forced-choice (2AFC) tasks: the Spearman-Kärber method.

  title={Threshold estimation in two-alternative forced-choice (2AFC) tasks: the Spearman-K{\"a}rber method.},
  author={Rolf Ulrich and Jeff Miller},
  journal={Perception & psychophysics},
  volume={66 3},
The Spearman-Kärber method can be used to estimate the threshold value or difference limen in two-alternative forced-choice tasks. This method yields a simple estimator for the difference limen and its standard error, so that both can be calculated with a pocket calculator. In contrast to previous estimators, the present approach does not require any assumptions about the shape of the true underlying psychometric function. The performance of this new nonparametric estimator is compared with the… CONTINUE READING