World 6

The player's mind

Motivation, reward, memory and bias: what is going on in the head of the person holding the controller, and how sure anyone really is.

A game happens in someone's head. They stay or leave because of what they feel, what they remember and what they believe the rules are, and none of that is in your code. These words name the mechanisms, including the ones used against players. The evidence varies a lot: some of this has held up for decades, some came from one small group of players, and some of the most quoted results have failed to replicate. Each entry says which is which, so you can use the idea without claiming more than anyone has shown.

Intrinsic motivationDoing something because the doing is the reward. Nobody plays tag for the points.
Extrinsic motivationDoing something for what it gets you: points, loot, money, a badge, or avoiding a penalty.
Self-determination theoryEdward Deci and Richard Ryan's theory that people thrive when three needs are met: autonomy (it was my choice), competence (I am getting good at this) and relatedness (other people matter here).
Overjustification effectRewarding people for something they already enjoy can make them do less of it once the reward stops. They come to see the reward as the reason they were doing it.
FlowThe state of being fully absorbed in a task that stretches your ability without overwhelming it, so that time seems to pass differently. Mihaly Csikszentmihalyi described it from interviews and experience sampling, from 1975 onward.
FieroThe burst of triumph after beating something hard, often with arms in the air. Nicole Lazzaro used the Italian word for pride in her 2004 "Four Keys to Fun" research, where it is the reward of what she called hard fun.
Power fantasyDesigning the game so that the player gets to feel overwhelmingly strong. The enemies exist to be swept aside.
Bartle's player typesRichard Bartle's 1996 paper sorted players of MUDs, which are text-based online worlds, into four kinds: achievers, explorers, socialisers and killers.
Operant conditioningBehaviour followed by a reward becomes more likely, and behaviour followed by nothing or by punishment becomes less likely. B. F. Skinner studied it from the 1930s onward.
Skinner boxA sealed cage with a lever and a food dispenser that Skinner used to study how the timing of rewards changes behaviour. He preferred the name "operant chamber". In games, "Skinner box" is an insult for a game that is mostly a schedule.
Variable rewardRewards that come after an unpredictable number of actions. It is the same pay on average as a fixed schedule, but you can never tell when the next one lands.
Compulsion loopA repeating cycle in which an action earns a reward, and the reward makes the next action possible or more appealing: fight, loot, upgrade, fight something harder.
Near-miss effectA loss that looks almost like a win, such as two jackpot symbols and a third one row off. The claim is that this feels closer to winning than other losses and makes people play on.
Hedonic adaptationGood things stop feeling as good as you get used to them. A reward is felt against what you have come to expect, not on its own.
Endowed progress effectPeople work harder towards a goal, and finish it more often, if they are given a head start, even when the amount left to do is the same. Joseph Nunes and Xavier Drèze named it in 2006.
Goal gradientEffort rises as you get closer to a goal. Clark Hull proposed it in 1932 and tested it with rats in a runway, which ran faster the nearer they were to food.
Zeigarnik effectThe claim, from Bluma Zeigarnik's experiments published in 1927, that people remember unfinished tasks better than finished ones. Her colleague Maria Ovsiankina reported the related urge to go back and finish.
CompletionismThe urge to finish everything a game offers: every item on the checklist, every marker on the map, the number to 100%.
Curiosity gapThe itch of knowing that there is something you do not know. George Loewenstein described curiosity in 1994 as a gap between what you know and what you want to know.
Loss aversionLosing something hurts more than gaining the same thing feels good. Daniel Kahneman and Amos Tversky built this into prospect theory in 1979, and in 1981 showed that wording alone can flip a choice.
Sunk cost fallacyCarrying on with something because of what you have already put in, even though that is gone whatever you do next. Only what comes from here on should count.
Endowment effectPeople value a thing more once they own it. Kahneman, Knetsch and Thaler's 1990 study gave students mugs, and owners asked about twice what others would pay for the same mug.
Gambler's fallacyBelieving that a run of one outcome makes the other more likely next, when each roll is independent. After five misses, a true 50% shot is still 50%.
Fudged oddsPlayers read probability badly, so games often show one number and use another. A shown 75% may really be 88%.
Peak-end rulePeople judge a past experience largely by its most intense moment and how it ended, and they pay surprisingly little attention to how long it lasted. Kahneman and colleagues showed it with cold water in 1993, and with colonoscopy patients in 1996.
Attribution of failureWhat people decide caused their failure: themselves or the game, something they can change or something they cannot. Bernard Weiner built this into a theory of motivation in the 1980s.
Cognitive loadHow much a person has to hold in mind at once. John Sweller developed cognitive load theory in 1988, from research on how people learn.
Mental modelThe picture a player builds of how the game works. It is only ever a guess, and it steers everything they try next.
FOMOThe worry that you are missing something other people are getting. Przybylski and colleagues gave it a formal scale in 2013. In games it is deliberately created by things that will not come back.
Dark patternA design that gets people to do something they would not choose if they saw clearly. Harry Brignull coined the term in 2010. Zagal, Björk and Lewis applied it to games in 2013.