Using forced choice discrimination to measure the perceptual response to light of different characteristics

Steve A. Fotios, Kevin W. Houser

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Forced choice discrimination-one of the fundamental procedures for comparing two or more stimuli-has been used in past studies to compare the relative spatial brightness of scenes illuminated by light sources of different spectra. This article-which focuses on spatial brightness perception but is relevant to other perceptual dimensions-suggests procedural steps for offsetting bias that can be expected in the discrimination task. The first step is to counterbalance the spatial locations of the two stimuli to offset position bias in simultaneous evaluations, or similarly to counterbalance the temporal locations to offset interval bias in sequential evaluations. The second step is to use an all-possible pairs approach when comparing the range of stimuli to offset stimulus range bias. We also suggest that multiple tests be carried out in a random order and that reports of the work present sufficient data to understand the procedure and to interpret the results. These procedural steps can be employed to improve practice in future work and can be considered as tools for screening past studies. Of 12 past studies that employed a discrimination procedure to investigate spatial brightness and preference under lighting of different spectral power distribution, only five were found to meet these criteria.

Original languageEnglish (US)
Pages (from-to)245-259
Number of pages15
JournalLEUKOS - Journal of Illuminating Engineering Society of North America
Issue number4
StatePublished - Apr 2013

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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