Separating kittens from the litter too soon is not good for the kitten and can lead to cat difficulties at the kitten gets older. Kittens learn a lot from their mothers, but even more from their litter mates and the social interactions help make for a better cat. Of course, kittens also need human socialization to help as well. A combination of other kitten and human socialization will make for a much easier cat.
Even though hunting is instinctual in the cat, the kitten learns how to stalk properly, chase, and ground prey better by playing with other kittens. Kittens don’t view their litter mates as prey, but the playtime better prepares them for the future and helps keep my minds actively engaged. The playtime also helps develop the kitten’s coordination faster. Better coordination means higher confidence in the kitten. Confidence is crucial in cats for them to live a healthy, happy life. Being around other kittens also help them burn their extra energy and socializes them to other cats. If your cat has spent time with other cats as a kitten, they are more likely to accept other cats in their future older lives.
Cats use their bodies, not their voices to communicate. Their purrs and vocalizations usually are a cry for their mother (you) to feed them. Kittens learn how to communicate with their bodies language and how to read other cat’s cues when they spend time with each other. This helps the kitten to learn boundaries, which is also beneficial to cat parents. For example, when a kitten bites or scratches too hard during playtime, the other cat or kitten will let them know. This will set the kitten up for how far she can take playtime in general, and you may sustain less painful scratches and bites in the name of playtime.
If you are thinking about adopting a kitten, consider adopting two from the same litter so they can develop together and learn how to be cats. With good socialization and love from you as well, all three of you will develop a strong and healthy bond.