  Determining whether perceptual properties are processed independently is an
important goal in perceptual science, and tools to test independence should be
widely available to experimental researchers. The best analytical tools to test
for perceptual independence are provided by General Recognition Theory (GRT), a
multidimensional extension of signal detection theory. Unfortunately, there is
currently a lack of software implementing GRT analyses that is ready-to-use by
experimental psychologists and neuroscientists with little training in
computational modeling. This paper presents grtools, an R package developed
with the explicit aim of providing experimentalists with the ability to perform
full GRT analyses using only a couple of command lines. We describe the
software and provide a practical tutorial on how to perform each of the
analyses available in grtools. We also provide advice to researchers on best
practices for experimental design and interpretation of results.
