Evidencefor response contraction bias in side-by-side matching tasks

Abstract

A recent study of lamp spectrum effects at mesopic levels employed side-by-side matching to investigate brightness. The results revealed an unexpected effect, identified here as a response contraction bias, normally only expected when judging individual stimuli. Response contraction bias causes subjective responses to be biased toward the middle of a response range. Although the bias is small its effect on brightness matching can be significant if the test procedure does not employ appropriate counterbalancing.

Stimulus range bias explains the outcome of preferred-illuminance adjustments

“…Figure 4 shows that the best fit line for mean preferred illuminances determined from the first stimulus range experienced by test participants is near parallel to that connecting the middle values of the three stimulus ranges. The best fit line for results determined following exposure to all three stimulus ranges suggests a response contraction bias to the three ranges as has been found in matching trials carried out at multiple illuminances; 13 the mean preferred illuminance in the low stimulus range is just above the mid point, whereas for the high stimulus range the mean preferred illuminance is just below the mid point of the range.…”

Using Category Rating to Evaluate the Lit Environment: Is a Meaningful Opinion Captured?

“…Though this article has raised criticism of category rating, that does not mean that category rating should be avoided but rather that researchers should take care when designing experiments and should be sceptical when considering conclusions drawn from category rating. Such scepticism should also be applied to the conclusions drawn from experiments using matching (Fotios 2001;Fotios and Cheal 2007b;Fotios, Houser and Cheal 2008), adjustment (Fotios and Cheal 2010;Kent et al 2017;Logadóttir et al 2011Logadóttir et al , 2013Uttley et al 2013) and discrimination procedures (Fotios and Houser 2013;Teller et al 2003). Note also that this article does not claim to provide an exhaustive review of the category rating procedure: the literature raises many other questions (Annett 2002;Brink et al 2016;Gescheider 1988;Gohardoust Monfared 2012;Heise 1969;Hyvärine 2015;Lietz 2010;Tourangeau et al 2000;Weisberg 2005).…”

White light in Road and Car lighting

“…In an article of Fotios and Cheal [8] is pointed out a bias, what is based on the testing facilities using in the presented study. The described effect seems however much smaller than the influence of the high blue content of the spectral distribution of LED.…”