Functions for Analyzing Psychophysical Data in R

An assortment of functions that could be useful in analyzing data from psychophysical experiments. It includes functions for calculating d' from several different experimental designs, links for m-alternative forced-choice (mafc) data to be used with the binomial family in glm (and possibly other contexts) and self-Start functions for estimating gamma values for CRT screen calibrations.



  • added an mafc link for the cloglog link, which permits fitting Weibull psychometric functions on a log stimulus axis. See example(mafc). v0.0-7
  • added mafc.weib link that is just an alias for mafc.cloglog
  • added mafc.cauchit link v0.0-8
  • added additional links that include parameters for both upper and lower
    asymptotes and a function, psyfun.2asym, that is a wrapper for glm and uses the new links to fit a psychometric function with variable lower and upper asymptotes. v0.0-9
  • added standard error estimates based on the Hessian from last iteration of optim to the output of psyfun.2asym (suggested by Ralph Pirow). v0.1-0
  • second graphic of mafc example set to aspect = "xy" for better rendition
  • modified column names of data set ecc2 from nyes, nno to Correct and Incorrect, better reflecting the meaning of these variables. v0.1-1
  • fixed an unmatched parenthesis in summary.lambda.Rd
  • fixed a double dot '..' in the name of an Rd file that did not belong v0.1-2
  • fixed some warnings for Rd files v0.1-3
  • dprime.SD was failing for small values of H and FA when equal (thanks to Paul Willis)


  • the argument name of the mafc links (mafc.logit, mafc.probit, etc.) has been changed from m to .m. This should permit these links to work with the glmer function in the lme4a, the development version of lme4.
  • dealt with some warnings concerning potential partial argument matching


  • added possibility for dprime.SD to give negative values (with a warning) for the IO method (suggested by Sverre Stausland)

  • increased the range of possible d' values obtainable from dprime.SD to 10 (was 5) for method "diff".


  • removed LazyLoad from Description


  • substituted binomial()$linkinv and binomial()$mu.eta for uses of .Call in mafc and mafc.logit and logit.2asym link functions.


  • eliminated some triple colons from examples

Reference manual

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0.2-3 by Ken Knoblauch, 21 days ago

Browse source code at

Authors: Kenneth Knoblauch

Documentation:   PDF Manual  

Task views: Psychometric Models and Methods

GPL license

Depends on stats, graphics

Suggests MASS, nlme, lattice

See at CRAN