People who appreciate the beauty of mathematics
activate1 the same part of their brain when they look at
aesthetically3 pleasing formula as others do when appreciating art or music, suggesting that there is a neurobiological basis to beauty. There are many different sources of beauty -- a beautiful face, a
picturesque4 landscape, a great
symphony(交响乐) are all examples of beauty
derived5 from
sensory6 experiences. But there are other, highly intellectual sources of beauty.
Mathematicians8 often describe mathematical formulae in emotive terms and the experience of mathematical beauty has often been compared by them to the experience of beauty derived from the greatest art.
In a new paper published in the open-access journal Frontiers in Human Neuroscience, researchers used
functional9 magnetic
resonance10 imaging (fMRI) to image the brain activity of 15 mathematicians when they viewed mathematical formulae that they had
previously11 rated as beautiful, neutral or ugly.
The results showed that the experience of mathematical beauty correlates with activity in the same part of the emotional brain -- namely the medial orbito-frontal cortex -- as the experience of beauty derived from art or music.
Professor Semir Zeki, lead author of the paper from the Wellcome Laboratory of Neurobiology at UCL, said: "To many of us mathematical formulae appear dry and
inaccessible12 but to a
mathematician7 an equation can
embody13 the quintescence of beauty. The beauty of a formula may result from
simplicity14, symmetry,
elegance15 or the expression of an
immutable16 truth. For Plato, the abstract quality of mathematics expressed the ultimate
pinnacle17(高峰) of beauty."
"This makes it interesting to learn whether the experience of beauty derived from such as highly intellectual and abstract source as mathematics correlates with activity in the same part of the emotional brain as that derived from more sensory, perceptually based, sources."
In the study, each subject was given 60 mathematical formulae to review at leisure and rate on a scale of -5 (ugly) to +5 (beautiful) according to how beautiful they experienced them to be. Two weeks later they were asked to re-rate them while in an fMRI scanner.
The formulae most consistently rated as beautiful (both before and during the scans) were Leonhard Euler's identity, the Pythagorean identity and the Cauchy-Riemann equations. Leonhard Euler's identity links five fundamental mathematical constants with three basic arithmetic operations each occurring once and the beauty of this equation has been likened to that of the soliloquy in Hamlet.
Mathematicians judged Srinivasa Ramanujan's infinite series and Riemann's functional equation as the ugliest.
Professor Zeki said: "We have found that activity in the brain is strongly related to how intense people declare their experience of beauty to -- even in this example where the source of beauty is extremely abstract. This answers a critical question in the study of
aesthetics18, namely whether
aesthetic2 experiences can be quantified."
Professor Zeki added: "We have found that, as with the experience of visual or musical beauty, the activity in the brain is strongly related to how intense people declare their experience of beauty to be -- even in this example where the source of beauty is extremely abstract. This answers a critical question in the study of aesthetics, one which has been debated since classical times, namely whether aesthetic experiences can be quantified."