This note is a critical review of the spatial brightness experiment reported by Kakitsuba
[Kakitsuba 2015]. There are several reasons why I think the study is flawed and therefore
that the results should not be considered credible. In particular, the results can largely be
explained by a stimulus range bias, the ‘boundary’ illuminances tending to lie near the centre
of each range of illuminances reported. Therefore the results are a product of the illuminance
ranges chosen by the experimenter and do not indicate observers’ preferences for light level
