Psychologists at the University of Rochester, in collaboration with Immersyve, Inc., a virtual environment think tank, asked 1,000 gamers what motivates them to keep playing. The results published in the journal Motivation and Emotion this month suggest that people enjoy video games because they find them intrinsically satisfying.

"We think there's a deeper theory than the fun of playing," says Richard M. Ryan, a motivational psychologist at the University and lead investigator in the four new studies about gaming. Players reported feeling best when the games produced positive experiences and challenges that connected to what they know in the real world.

The research found that games can provide opportunities for achievement, freedom, and even a connection to other players. Those benefits trumped a shallow sense of fun, which doesn't keep players as interested.

"It's our contention that the psychological 'pull' of games is largely due to their capacity to engender feelings of autonomy, competence, and relatedness," says Ryan. The researchers believe that some video games not only motivate further play but "also can be experienced as enhancing psychological wellness, at least short-term," he says.

Ryan and coauthors Andrew Przybylski, a graduate student at the University of Rochester, and Scott Rigby, the president of Immersyve who earned a doctorate in psychology at Rochester, aimed to evaluate players' motivation in virtual environments. Study volunteers answered pre- and post-game questionnaires that were applied from a psychological measure based on Self-Determination Theory, a widely researched theory of motivation developed at the University of Rochester.

There are a few certainties in life - death, taxes, clichéd opening sentences like this, and Virtua Tennis' game design. Honestly, watching Virtua Tennis evolve is like watching grass grow - it's pretty bloody slow, and you can basically shut your eyes and still know where it's headed. That's not to say that the Virtua Tennis games are in any way bad - as far as grass growing, this is pretty good stuff; it's just that with each iteration, it's harder to justify spending more money for what is essentially a very similar experience. There's nothing fundamentally wrong with Virtua Tennis 3, and in fact, the core gameplay is as good as ever, but it just doesn't take the step forward that it could, and probably should. Particularly in its PS3 incarnation, but more on that later.

Somewhat critical introduction out of the way, there is a lot to like about this game. SEGA nailed the sense of movement and the ball physics right from the first game in the series, and these elements have continued to improve. Player animations are stunning for the most part, only falling down occasionally by virtue of the fact that they are so good. When you see a player sprinting back down the line in an attempt to reach the ball while he's still facing forward, for instance, it doesn't gel with what you know the player's intent would be - to simply get to the ball. If anything these moments are a compliment - as with any game that emulates real life, the closer you get to reality, the more you'll pick up on minor flaws. By and large Virtua Tennis 3 is a joy to watch, and even after extended play you'll still see the odd animation you haven't come across yet.