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.
Istraživači su iskoristili prednost ove činjenice lažiranjem dvije gumene bradavice tako da ako beba siše jednu, čuje snimku majčinog glasa na slušalicama, a ako siše na drugoj čuje snimku glasa strane žene.