Even in virtual worlds, life is what you make of it. A study has found that gamers have more fun when they think a video game has been updated with fancy new features – even when that’s not true.

Paul Cairns, a professor of human-computer interaction at the University of York, UK, wondered if the placebo effect translates into the world of video games after watching a TV programme about how a sugar pill had improved cyclists’ performance.

“People have a preconception that a little round white pill that doesn’t taste nice will have a certain effect on their physiology,” says Cairns. “It’s changing your perceptions of the world around you in some profound way.”


To test their idea, he and colleague Alena Denisova asked 21 people to play two rounds of Don’t Starve, an adventure game in which the player must collect objects using a map in order to survive.

In the first round, the researchers told the players that the map would be randomly generated. In the second, they said it would be controlled by an “adaptive AI” that could change the map based on the player’s skill level. After each round, the players filled out a survey.

In fact, neither game used AI – both versions of the game were identically random. But when players thought that they were playing with AI, they rated the game as more immersive and more entertaining. Some thought the game was harder with AI, others found it easier – but no one found it equally challenging.

“The adaptive AI put me in a safer environment and seemed to present me with resources as needed,” said one player.

“It reduces the time of exploring the map, which makes the game more enjoyable,” said another.

A different experimental design, with 40 new subjects, confirmed the effect. This time, half of the players were put in a control group and told that the game was random, while the other half thought the game had built-in AI.

The work was presented earlier this month at the CHI PLAY conference in London. The team say video game creators need to keep the placebo effect in mind when developing and testing new games.

The experiments show convincing evidence that expectations influence people’s gaming experiences, says Walter Boot, a psychologist at Florida State University who studies video games. The effect doesn’t have to involve fancy features like AI – it could just work if people think the game they’re playing is the latest version on the market, he says.

“The expectation is that something new must be better than the thing before,” says Boot. “Maybe that’s why people go with a new iPhone every few years.”