Just noticeable differences are proportional to baseline stimulus size

Evidence

Note that there is a trend here: As the size of the weight increases, the amount needed to differentiate between weights increases. However, the increase occurs in a systematic way ​ — for each weight lifted, the just noticeable weight difference is a change of 10% (a proportion of 0.1) in the weight. In this case, the pattern is 10 versus 11, 50 versus 55, and 100 versus 110 lbs, or a 10% difference in weight across the various baseline weights. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 799