Wiseman found that joke themes kept recurring, too. "There seem to be only about four jokes that come up all the time," he told me. "Someone trying to look clever and taking a pratfall. Husbands and wives not being loving. Doctors being insensitive to imminent death. And God making a mistake.
"We've learned one thing for sure, though," he continued. "Comparing scores for the same joke with different animals inserted in it, we found that the funniest animal of all is a duck. So science has determined that, if you're going to tell a talking-animal joke, make it a duck."