She's the same soft, cuddly friend that responds to baby's touch with silly sayings and sing-along songs – but now Sis has Smart Stages technology that changes the learning content as baby grows! Because every baby develops at their own pace, Smart Stages technology gives you the ability to select the stage that's best for your child. There are a variety of developmentally appropriate songs, phrases and sounds within three levels of play. Sis' light-up heart even twinkles along to the music!