I've looking around Google Scholar for the earliest mention of this particular classifier and have not had much luck finding a definitive source. I've seen some sources cite as late as the 1980s and other as early as the 1930s. Does anyone know when the Naïve Bayes Classifier was developed and/or first used as a classification technique?
A naive Bayes classifier is a simple probabilistic classifier based on applying Bayes' theorem with strong (naive) independence assumptions.
Bayes' theorem was named after the Reverend Thomas Bayes (1702–61), who studied how to compute a distribution for the probability parameter of a binomial distribution. After Bayes' death, his friend Richard Price edited and presented this work in 1763, as An Essay towards solving a Problem in the Doctrine of Chances.
So it is safe to say that Bayes classifiers have been around since the 2nd half of the 18th century.
Especially as Stephen Stigler suggested (in 1983, Stephen M. Stigler, "Who Discovered Bayes' Theorem?" The American Statistician 37(4):290–296) that Bayes' theorem was discovered by Nicholas Saunderson some time before Bayes. On the other hand Edwards (1986) disputed that interpretation (in 1986, A. W. F. Edwards, "Is the Reference in Hartley (1749) to Bayesian Inference?", The American Statistician 40(2):109–110).
Which takes us back to the safe assumption of "2nd half of the 18th century" again, as a naive Bayes classifier is a simple probabilistic classifier based on applying Bayes' theorem... which makes it "naive" is that it comes with strong (naive) independence assumptions. But practically, it's the same theorem.
I have seen the following paper cited before for Naive Bayes:
Hand, D. J., & Yu, K. (2001). Idiot's Bayes—not so stupid after all?. International statistical review, 69(3), 385-398.
It is a bit of a review and discussion of the topic.