Early sensory experiences are how babies learn initially. Sensations received throught the senses: touch, taste, sight, smell, hearing, proprioceptive and vestibular (balance) are interpreted by the brain to form and connect neurons. These form the basis of further development and higher levels of functioning.
The wider the variety of sensory experiences a newborn is exposed to, the more these neurons form and develop. These toys are designed to provide these such experiences that babies and toddlers will love.