english: Researchers take advantage of this fact by rigging up two rubber nipples, so that if a baby sucks on one, it hears a recording of its mother's voice on a pair of headphones, and if it sucks on the other nipple, it hears a recording of a female stranger's voice.
non_english: Vedci využili tento fakt a pripravili dva gumové cumle tak, že, keď dieťa saje z jedného, v slúchadlách začuje hlas svojej matky. Ak saje z druhého cumľa, ozve sa záznam hlasu cudzej ženy.