Answers are grounded in this paper and cite their sources.
As an approximation based on various experiments reported in the literature, the least detectable difference in speed (delta w) varies in direct proportion to the speed (w) over a range from 0.1 to 20 degrees of visual angle per second. The constancy of the Weber ratio (deltaw/w) aids in understanding how men react to velocity in various situations.
No takes yet. Share an insight, caveat, or question.
Robert H. Brown (1960) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: