Cognitive: Everything is new for your baby: sounds, flavors, feelings, shapes, smells.
Sensory: Baby sees at a distance of 8-12 inches and in two shades: dark and light. Therefore, all dark colors are perceived as black and the light ones as white. Showing them objects with color contrast and sound will incentive the baby to track the object visually and eventually with their head. Besides, it helps them develop concentration.
* Baby's’ nervous system start to develop. Be aware of the volume and amount of noise you use, as the world seems very noisy to your new born.