1. How to develop your baby\’s cognitive ability. When babies are 3 months old, they begin to become interested in the things around them. This is the best period to develop their cognitive ability. You can help babies develop cognitive abilities in the following ways: 1. Interact face-to-face with babies and imitate their expressions and sounds; 2. Provide toys of various colors, shapes and textures for them to touch, explore and explore; 3. .Give them enough time to play freely without interfering too much. 2. How to promote the baby’s language development. Around 3 months, the baby starts to say “ahhh”,