Overseas research reveals that even a three-day-old infant can distinguish different voices and shows a preference for the voice and scent of its own mother (or the person who habitually looks after it).
國外則有研究顯示，剛出生三天的嬰兒，就可以認出不同的說話聲音，還會顯現出對母親（或一直照顧他的人）的聲音和氣味的偏愛。