An earlier post, Disease Control, cited some US Centers for Disease Control and Prevention research that lamented the fact that attempts to debunk health myths failed to a large extent because they repeated the myth, and that's what subjects remembered, with the kicker that it was from an authoritative source!

When ... social psychologist Norbert Schwarz had volunteers read the CDC flier, however, he found that ... three days later, they remembered 40 percent of the myths as factual. ... Most troubling was that people ... now felt that the source of their false beliefs was the respected CDC.

I responded that "just any old smear won't do. It has to have legs. It isn't that "whoever makes the first assertion about something has a large advantage over everyone who denies it later", it is that a good smear is difficult to refute". Perhaps I am mistaken, Facts Prove No Match for Gossip, It Seems.

“If you know you already have the full information about someone,” he said, “rationally you shouldn’t care so much what someone else says.”

So why do we? “It could be,” he suggested, “that we are just more adapted to listen to other information than to observe people, because most of the time we’re not able to observe how other people are behaving. Thus we might believe we have missed something.”

This makes a certain sense, but I still wonder if evolution has taken a Chico Marxist turn here. In “Duck Soup,” Chico tries to pass himself off as Groucho’s character, complete with moustache and cigar, but encounters a skeptical Margaret Dumont, who protests that she just saw Groucho leave the room.

“Well, who you gonna believe, me or your own eyes?” Chico asks.

Now, at last, we know the answer.

In real life I say I never gossip, and do my best to resist the efforts of others digging for some. It's not possible to completely decline to give information about others, and in hindsight I sometimes realize that I did in fact gossip, even when using disclaimers about the reliability of hearsay information or the sparseness of my direct observations. I'll be even more careful now.