[schoen]

The FSF has had this 1987 newspaper article on their web site for a long time:

https://www.gnu.org/philosophy/motivation.html

There's also a psychology experiment in which people who were paid to argue for a position reported less belief in it afterward compared to people who argued for it for free (but I don't remember the citation). Apparently all of these things may be described as

https://en.wikipedia.org/wiki/Overjustification_effect