A game developer can "tag" an item in the game environment. When an
animated character walks near the "tagged" item, the animation engine can
cause the character's head to turn toward the item, and mathematically
computes what needs to be done in order to make the action look real and
normal. The tag can also be modified to elicit an emotional response from
the character. For example, a tagged enemy can cause fear, while a tagged
inanimate object may cause only indifference or indifferent interest.