The Sims 4's next expansion will make Sims actually care about each other's personalities

The Sims 4's next expansion, Growing Together, and the incoming free update for the base game are adding a lot of new outfits and furniture and a proper infant life stage, but the really exciting thing is the expansion's deeper simulation of relationships, which looks like it's entering straight-up strategy game territory. It's enough to make a Build Mode purist like me a little jealous.

In a presentation of the expansion's features, Maxis showed off lots of Create-A-Sim features with Live Mode implications. Most interesting among them are the new social likes and dislikes and the family dynamics system. In the same way you can choose preferences for music styles or activities for your Sims, you'll also be able to determine what kinds of traits and interactions they enjoy from other Sims. They might like funny Sims and prank interactions but dislike homebody Sims and physical intimacy, for example.

Over in the household relationships portion of Create-A-Sim, you'll have a new dropdown menu for "family dynamics" with options like "supportive," "difficult," or "jokesters" to define relationships between each member of the household. Likes, dislikes, and dynamics can all be set ahead of time in CAS, but can also emerge through gameplay for you to approve in the way that Sims will sometimes ask if they should decide they like painting, for instance.

That all feeds into the new compatibility rating that you can find in the relationships panel in Live Mode. For each two Sims, their total likes, dislikes, traits, and existing dynamics are assessed to generate a compatibility rating ranging from "amazing compatibility" down to "bad compatibility" to let you know how they're likely to get on.

Oh, and all of these new likes, dislikes, dynamics, and compatibility indirectly feed into the existing Sentiments system that allows Sims to retain memories about good and bad interactions with others which influence their moods and disposition in the future. 

This all sounds like it's going to add lots of weird, emergent situations when you leave your Sims to their own devices. Personalities will collide more than ever before, even when you're directing them through conversations. It's not as complex as, say, Crusader Kings 3, but looking at all the new systems in the interface brings back my memories of diving into menus to figure out why these two rulers won't stop antagonizing one another like that. I've always bounced off Live Mode, but this expanded layer of simulation is pretty enticing.

The free base game update is bringing a lot of worthwhile additions specifically to infants. Sims will now be able to invite another to "have a science baby" regardless of romantic status—a feature I'm sure won't totally have weird bugs at launch that cause inappropriate science baby invites. Infants will be part of Create-A-Sim now too, with their own outfits, traits, and moodlets. There are new bassinets and cribs, baby gates, toys, diaper shelves, and other important nursery furniture in the free update.

You can find more about all the planned features over on The Sims 4 site or watch the developer livestream today to see it all in action. The Growing Together expansion will launch on March 16 over on Steam and the EA store for $40. The base game infants update is scheduled for March 14.