
From the BBC:
http://news.bbc.co.uk/1/hi/world/south_asia/7737798.stm
"Ripley: Why do you care about them? Annalee Call: Because I'm programmed to. Ripley: You're programmed to be an asshole? You're the "new model" asshole they're putting out?" Alien Resurrection, 20th Century Fox, 1997.
If you do a web search on this topic, you will get all kinds of studies pointing out why training at one time or another in the day is best ...