Babies as young as 5 months develop quite satisfactory reasoning power, and are capable of distinguishing between various tunes, whether it is “Ode to Joy” from Beethoven's Ninth Symphony, or a sad and depressive one
This was concluded through an experiment conducted by the researchers, in which the babies were exposed to an emotionally-neutral face, while the music played. The music would stop when the baby would look away from the face and instead another sad song would start playing.