It's because games have a few tricks up their sleeve when it comes to keeping you in that chair, eating away at your sleep hours. Tricks that they've honed through years of practice, often ripped from the depths of psychological research, all designed to keep you playing. So let's take a look at a few of them! Wouldn't that be nice?
1. The Infamous Skinner Box
This had two effects. First, it allowed him to join Pavlov and Schrodinger in the "Most Bizarre Use of Animal Subjects" category, but more importantly, it allowed him to map a direct correlation between the frequency of the reward, and how long the subject was willing to continue performing that action. To give away the ending, it turns out random rewards motivate the desired behavior for far, far longer than consistent or strictly scheduled rewards. And thus, this magical button-pushing, food-dispensing chamber was nicknamed "The Skinner Box".Then the games industry got a hold of this idea, and went to town with this. Most often, you will see this principle in place with MMO's such as World of Warcraft. Such games thrive on keeping players performing actions, long past the point where those actions are still "fun". The key to their strategy is a random reward system, where quests or enemies will only drop the best loot a small percentage of the time. The advantages to this are twofold. On one hand, it can keep a player going for much longer, each time hoping that it's their turn to be 'lucky'. And on the other hand, it increases the players sense of accomplishment for each random reward. That sense of accomplishment is certainly going to come to mind the next time they are in the middle of a four hour grind.
2. Never Letting You Say No
No, this is domain of online multiplayer, most obvious in a variety of first person shooters. The strategy most often employed is to have the player in another game before they can even wonder about turning it in. Let's use Team Fortress 2 as an example. The progression is quick. Upon the games completion, you'll view your stats for that round as the game wraps up. After that, a (relatively) short loading screen with accompanying lifetime stats to keep you distracted and then bam, you're right at the start of another game. It's much harder to pack it in when you're staring down the barrell at a fresh round, and Team Fortress 2 manages to keep you distracted just long enough to get you to that point.
3. Giving Your Habit a Jumpstart
It seems fairly self evident. If the first level took you ten hours to gain, most players would barely make it out fo the gate. Instead, the game slowly ramps up the length of time it takes for you to gain a level. So at first you may gain five levels in a sitting, and then three, and then one. Then you'll find yourself putting in more hours in a sitting to gain that next level, simply because you've been conditioned to think that this level progression is the sign of a successful sitting. I know I did.
On a similar note, notice how by the time you've left the training area, you'll likely have at least one nice, shiny piece of gear? Of course you do, effectively giving you a taste of an MMO's other key game mechanic: loot.
4. The Feedback Loop
Video Games fly straight in the face of this.
Few things in the world have a shorter feedback loop than your average video game. At the shortest, you might have a few seconds in between an action and the reward. At worst, you may be waiting twenty minutes until the end of the mission to get your reward. But the point is that games will rarely let you go too long before it makes you feel rewarded for your actions.
The best example of this is multiplayer in Call of Duty. The whole "fire guns, get kills" mechanic isn't the feedback that I'm generally referring to, players tend to take that for granted. But Call of Duty finds plenty of other ways to provide rewards. Kill streaks, prestige ranks, equipment unlocks, end game stats and Live achievements are all ways that CoD manages to let you know just how awesome you are, and it keeps you coming back for more.
Now, I'm not saying that any of these methods are particularly heinous(though the Skinner Box is a little manipulative...), but I've always found it interesting to look at some of the underlying concepts we may take for granted in video games. All that we have is food for that, and maybe, once in a while, we'll ask ourselves why we're still playing a certain game at 3am on a work night.