They are stony eyes, but they can arouse a rush of emotions in those staring at them.
An eye-to-eye meeting with Michelangelo's Moses triggers the highest emotional responses, says a study which measured the emotional and cognitive engagement during the observation of a sculpture masterpiece.
Previous researchers have investigated the emotional impact produced by great works of art, but such studies were all based on surveys and lab experiments.
"Our research is the first ever that collects brain activity during the observation of a sculpture in its original setting," Fabio Babiloni, professor of physiology at the University of Rome Sapienza, told Discovery News.
To assess the cerebral and emotional reactions a sculpture can trigger, Babiloni and colleagues examined a group of 20 healthy subjects. For each onlooker, the researchers, in collaboration with the university spin-off Brainsigns, simultaneously collected the neuroelectrical brain activity (through EEG), heart rate (HR) and galvanic skin response (GSR), which basically measures the skin's sweat gland activity.
"While the emotional engage is described by mixing the HR and GSR, the cognitive factors are indexed by the estimation of the EEG asymmetry over the prefrontal cortex," the researchers wrote in a paper which will be presented in August at the International Conference of the IEEE Engineering in Medicine and Biology Society in Chicago.
Basically, relatively greater left frontal activity indicates a propensity to engage a stimulus, while relatively greater right frontal activity shows disposition to withdraw from it.
It emerged that cognitive and emotional responses triggered by the contemplation of Moses vary in relation to the different points from which the sculpture is viewed.
"Emotions raise to very high levels when observers meet the statue's eyes," Babiloni said.
Part of Pope Julius II's tomb in the basilica of St. Peter in Chains in Rome, Moses is an imposing marble statue carved in a niche. Michelangelo, who worked on the tomb project for 40 years, between 1505 and 1545, considered it his most accomplished, life-like creation.
Legend has it that the sculpture produced deep emotions in the artist himself.
As he finished it, Michelangelo is said to have struck the right knee with a hammer and said, "Now speak!"