Proc. R. Soc. B doi:10.1098/rspb.2009.1788 (2009)


Humans can distinguish between similar-sounding words regardless of the speaker. Debate has centred on whether this ability is unique to humans or exists in other animals and contributed to the evolution of human speech.

To tackle the question, Verena Ohms of the Institute of Biology Leiden in the Netherlands and her colleagues recorded 21 men and women saying the Dutch words 'wit' and 'wet', then played them back for eight zebra finches (pictured). Enticed by birdseed, the finches learned to discriminate between the two words. The birds could still tell the two apart when the words were spoken by people they hadn't heard before, including people of the opposite sex.