In the 1970s, the roboticist Masahiro Mori speculated about a threshold of realism up to which humans empathize with robots. However, when the robot’s appearance and movement improve beyond that, humans are repulsed instead. This problem is known as the Uncanny Valley. But as the realism increases further, reactions slowly match human empathy levels.

Now, the Uncanny Valley has become a problem for computer graphics also, although in some pre-rendered cases, animation is good enough to fool humans. The question is, does this really cause problems for video games? Aren’t these reactions to AI characters perfect for creating an emotional experience for the player?

For example:

• In Bioshock, Irrational/2K managed to create a very spooky environment, particularly using the “little sisters” in the game. The strange feeling of familiarity together with the horrific setting brings out strong emotions in the player.

• In Half-Life’s Episode 2, Alyx plays an important role throughout the game, accompanying and interacting with the player. Valve did a great job in building a positive emotional bond between the player and Alyx.

What is there to learn from these examples for designing AI characters? How do you exploit the uncanny valley when creating negative emotions, but yet avoid it when aiming for positive emotions? What do you expect to see as developers take the levels of realism in animation even further?

Next week: Your favorite AI moments in gaming.