Electronic Arts and Maxis promise that the characters you create in The Sims 4 will be smarter, feature unique personalities, and stand out with some very emotional reactions.
Specifically, players will obviously be able to customize the appearance of their characters, but they'll also have the opportunity to shape each sims personalities and define characters by their traits and activities. When a sim has an aspiration, you can ignore it or pursue it but your Sim will react depending on what you choose to do.
Maxis is also working to add new emotions, offering control over a character's mind, body, "and now the heart of your Sims." You can control your character's emotions but the activities and events in life will clearly drive a lot of that interaction.
For more on The Sims 4, stick with GameRevolution. We'll have a hands-on preview shortly.