For as long as I’ve been playing The Sims (which is more than ten years now), their tiny lives have been defined by what they need at any particular moment: money, new TV, lunch, a shower, a pee (always with the peeing). The Sims 2 and 3 made the little computer people more relatable, adding in aspirations and expressions and stronger personality traits, but their limited emotions were still dependent on their needs and how fulfilled they were. In The Sims 4, their needs will be dependent on their emotions.
For the first time Sims have persistent emotional states. Rather than just being happy or sad, fulfilled or unfulfilled, they can be depressed, angry, flirty, vulnerable – and when they’re in these states, it affects what they can do and how. Angry Sims will work out harder, depressed Sims won’t feel like doing much. They look like they feel, too – hunched shoulders, clenched fists, quivering lips. Instead of being about fulfilling their need (or not), the game becomes about manipulating their emotional states to run their lives, rather than manipulating their circumstances by, say, buying them stuff or walling them into a room with no toilet.