coarse marmosets , Callithrix jacchus , are vocal little monkey from South America with a hearing image standardized to that of humans . And like us , it appears these New World primates can perceive pitch .
The findings , bring out inProceedings of the National Academy of Sciencesthis week , suggest that sure expression of pitch perception emerge early in the evolution of primates . Our species have been divide by at least 40 million years .
Being able-bodied to perceive the levelheaded quality recognise as pitch think of distinguishing between mellow and low notes . For humans , it ’s essential for action speech and making music . But are the underlying mechanisms of tar perception unique to just us ? Recent written report with two Old World macaque monkeys and the coarse marmoset – which is located between macaques and non - primate mammals on the evolutionary tree – point that we ’re not the only ones with pitch sensing abilities .
Marmosets have a rich outspoken repertory : phee , chirrup , ballock , moan , and squeal calls , just to name a few . And the nerves in a brain area called the principal audile pallium respond to pitch - evoking sounds in a similar manner to our encephalon .
To see if primates perceive pitch shot the way we do , a Johns Hopkins squad led byXindong Songgave learn examination to four manlike adult common marmosets train to lap up a feeding tube near its mouth for a food advantage after hearing a change in pitch . During examination , the marmosets were seated in the shopping mall of a sound closing off chamber line with loggerheaded acoustic immersion froth ; sound were toy through a speaker powered by an amplifier mount 40 centimeters ( 15 inches ) in front of the monkey .
The marmoset parade all three main features of human pitch perception . First , mass are better at distinguishing differences in pitch at dispirited rather than high frequencies . Next , we pick up on elusive change in the spread between pitches at broken frequencies . For example , we comment if a serial of tones increases by just 100 cycles/second . And finally , at high frequence , people ’s ability to perceive pitch differences among simultaneous tone is related to how sensible they are to the beat of sound waves .
Together , these findings paint a picture that human - like sales talk percept chemical mechanism originated comparatively ahead of time in primate development – perhaps as early as ( or even earlier than ) 40 million year ago when New World and Old World order Primates ( like us ) split . As sketch authorXiaoqin Wangof Johns Hopkins explains in astatement : " Now we can explore question about what goes wrong in people who are tone deaf and whether perfect pitch is an inherited or learned trait . "
