Night owls probably couldn't become morning people??

Today's blog from below URL.

http://lifehacker.com/5310985/peak-performance-times-for-morning-people-and-night-owls

The blog said some research showed that night owls probably couldn't become morning people.
Really??
Actually, I usually get up early in the morning and I used to get up late when I was young. In addition that, this research's participants were only 18 person so it's a little difficult for me to trust this research.