The song is called 'The Happy Song' and it is scientifically designed to make your baby smile.
According to multiple studies babies prefer consonance over dissonance, and prefer the female voice, especially when it’s in a singsong baby talk voice. The quick tempo, and repetitive melody that includes drum rolls, key changes, rising pitch glides, and plenty of opportunities for anticipation and surprise. Plus, there are silly noises, and babies love those.
The song is written, and performed by Grammy award winner Imogen Heap.