Umm...these people either have been reading too much xkcd or not enough: http://xkcd.com/531/
I thought this was an article about test subjects who very strangely called the scientists Mom or Dad when they came in for a study.
Or about test subjects that are encouraged or required to call the scientist/experimenter Mom or Dad in order to foster familial or subordinate behavior. I guess that would be mostly useful in psychological tests though.
So, is tickling learned or innate? How can they leave me hanging like that.
Meh... gives me the 'register to see the article' screen...