In the late 1980s and early 1990s, he published papers showing how people use arbitrary categories to make judgments. (discovermagazine.com)
It forces your pupils into three quite arbitrary categories, and doesn't give you an idea of the full range within each grade. (blog.nomoremarking.com)
Another bias is mental accounting where an investor divides wealth into arbitrary categories and makes irrational decisions based on the category, such as a stock purchase or sale tied to an emotional attachment to the company. (morganstanley.com)