In case my previous note on the law of small numbers confused anyone, I’ll compare it to the law of large numbers.
The law of large numbers is a mathematical theorem; the law of small numbers is an observation about human psychology.
The name “law of large numbers” is a standard term applied to a theorem about the convergence of random variables. (OK, actually two theorems. Like nuclear forces, the laws of large numbers comes in a strong and a weak form.)
The name “law of small numbers” is a pun, and I don’t believe the term is commonly used. Too bad. It’s a convenient label for a common phenomena.