Jane McGonigal, a game designer and researcher at the Institute for the Future, sums up the new argument in her coming book, “Reality Is Broken: Why Games Make Us Better and How They Can Change the World.” It’s a manifesto urging designers to aim high  why not a Nobel Prize?  with games that solve scientific problems and promote happiness in daily life.

In the past, puzzles and games were sometimes considered useful instructional tools. The emperor Charlemagne hired a scholar to compile “Problems to Sharpen the Young,” a collection of puzzles like the old one about ferrying animals across a river (without leaving the hungry fox on the same bank as the defenseless goat). The British credited their victory over Napoleon to the games played on the fields of Eton.

But once puzzles and gaming went digital, once the industry’s revenues rivaled Hollywood’s, once children and adults became so absorbed that they forsook even television, then the activity was routinely denounced as “escapism” and an “addiction.” Meanwhile, a few researchers were more interested in understanding why players were becoming so absorbed and focused. They seemed to be achieving the state of “flow” that psychologists had used to describe master musicians and champion athletes, but the gamers were getting there right away instead of having to train for years.

One game-design consultant, Nicole Lazzaro, the president of XEODesign, recorded the facial expressions of players and interviewed them along with their friends and relatives to identify the crucial ingredients of a good game. One ingredient is “hard fun,” which Ms. Lazzaro defines as overcoming obstacles in pursuit of a goal. That’s the same appeal of old-fashioned puzzles, but the video games provide something new: instantaneous feedback and continual encouragement, both from the computer and from the other players.

Players get steady rewards for little achievements as they amass points and progress to higher levels, with the challenges becoming harder as their skill increases.