08.11.2022

New article accepted for publication in the Journal of Vision

Title: "Estimating the perceived dimension of psychophysical stimuli using triplet accuracy and hypothesis testing" by David-Elias Künstle, Ulrike von Luxburg and Felix A. Wichmann

Abstract:
Vision researchers are interested in mapping complex physical stimuli to perceptual dimensions.
Such a mapping can be constructed using multi-dimensional psychophysical scaling or ordinal embedding methods.
Both methods infer coordinates that agree as much as possible with the observer's judgments so that perceived similarity corresponds to distance in the inferred space. However, one fundamental problem of all methods that construct scalings in multiple dimensions is that the inferred representation can only reflect perception if the scale has the correct dimension.
Here we propose a statistical procedure to overcome this limitation. The critical elements of our procedure are (i) measuring the scale's quality by the number of correctly predicted triplets and (ii) performing a statistical test to assess if adding another dimension to the scale improves triplet accuracy significantly.
We validate our procedure through extensive simulations. In addition, we study the properties and limitations of our procedure using "real" data from various behavioural datasets from psychophysical experiments.
We conclude that our procedure can reliably identify (a lower bound on) the number of perceptual dimensions for a given dataset.