Hacker News Reader

Page & Neuringer (1985) showed that you could teach pigeons to be more variable. The discussion around that phenomenon has similar branches: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3501427/

More recent review: A Critical Review of the Support for Variability as an Operant Dimension https://pubmed.ncbi.nlm.nih.gov/33024930/