Biologically perhaps, psychologically no. This "trick" you speak of is the sense of progression and rewards given that makes a game fun to play.
I've never once seen a game that is not fun, but is addicting. Although my friends have said Master of Orion 3 fits that description, but I never actually saw them ever play it so I think it was a joke.
If somebody knows where to find the talk please post it, my google-fu is weak today. He also compares the iphone to a swiss army knife and the ipad to a "swiss-army-kitchen-utensil" (i.e too bad to be really useful and too big to fit in your pocket). The talk was just a few weeks after the first ipad release. It also contains alot of other talk about the future of gaming for the general masses, facebook games and gaming anything in life(like shopping), etc. If that's enough to trigger anyones memory.
http://www.g4tv.com/videos/44277/dice-2010-design-outside-th...
The farmville comparision i was refering to is probably this one http://mediacommons.futureofthebook.org/content/cultivated-p...