Humans and chimp are pretty in effect at recognizing faces . But when faces are upside down , we both happen it much more difficult to identify them than other reverse objects . This is thought to be because we use spatial cue to recognize font . But how well do you opine you would recognize a butt ? Well , it seemschimps are just as confuse at recognizing invert grimace as they are when realise inverted cracks – the same can not be say for man however .
Known as the “ face inversion issue ” , it has been observe that while unremarkable physical object shown upside down are well-fixed to identify because we depend at the item as a whole , it is not the same with faces . When faces are shown invert , it takes slightly longer for our mental capacity – which have a specific facial acknowledgement zone – to litigate .
When scientists tested this phenomenon with other consistence parts , they found no interchangeable effect , until now . A raw small-arm of inquiry from theUniversity of Leidenhas found that chimps take slightly longer to recognize inverted butts , just as they do with expression . “ This is a unspoiled denotation that this category has precedency over other family of objects,”saysMariska Kret , who co - authored the study publish inPLOS One .
Pan troglodytes arse ( left ) show similar symmetrical features to human facial expression ( right ) . Kret et al . 2016
It implies that something similar is going on in the cognitive processing of face and bums , and could even ply perceptiveness into our own evolution . In chimpanzees , the female show they are sexually centripetal through the enlarging of their arses , which also flush red . The source paint a picture , perhaps rather controversially , that throughout our evolutionary history , face and stub have played a similar role , and that human are using a like cognitive summons to recognize them .
“ The finding evoke an evolutionary shift in socio - intimate signalling function from behinds to faces,”write the authors , “ two hairless , symmetrical and attractive body contribution , which might have attune the human learning ability to process fount , and the human facial expression to become more behind - like . ” They go on to state that the lack of pilus may enable colour to become more obvious , something that they take is raise by the improver of blusher and red lip rouge .
So while chimps may be encounter butts in the same direction as they see faces , we ’ve fall back this aspect as focal point shifted in the first place to our " behind - same " faces .
