The latest edition of neurology journal Brain has an extended review of three books about the history of the senses which gives a fascinating insight into how the meaning of our sensory experiences has changed over the centuries.
This paragraph is particularly interesting as it relates medieval theories of perception to the superstition of the ‘evil eye‘ where you could curse someone by looking at them.
While we now think of vision as a system for interpreting passively received light, the ‘evil eye’ makes much more sense when you realize that medieval people thought that light rays could fundamentally influence what they touched and even that the eyes actively sent out rays that could influence the objects within sight.
In 1492, learned debates also influenced how the world was perceived. As medical historians Nancy Siraisi and James T. McIlwain, also a neuroscientist, point out, medieval scholars would have located sensory perception in the brain (Siraisi, 1990; McIlwain, 2006). However, they would have perceived the five senses as active entities conveying information about the outside world to the internal senses of common sense, imagination, judgement, memory and fantasy (the ability to visualize).
Scholars differed considerably over how this worked in practice: for example, were rays emitted from the eyes towards the viewed object or was it the other way round? Either theory allowed for these rays to influence both viewer and object, thus explaining the widespread concept of the evil eye, or a belief still current in the 18th century that what a mother saw affected her foetus. The brain, however, was not the only sensitive organ of the body.
The heart was believed to be the centre of the animal soul, and thus closely associated with more carnal senses such as touch. The brain, the centre of the rational soul, was more closely associated with sight; the eyes often viewed as the ‘windows of the soul’. Sight, therefore, was given pre-eminence in the pre-modern world as it is today, but often for spiritual reasons due to the inter-dependence of religion and rational knowledge (scientia).
Thus even if the brain functioned in the past very much as it does today, the emotional and moral meaning of sensory experience differed dramatically.
The whole review is worth reading in full, not just because of the insights into medieval psychology, but also because these new books introduce ‘sensory history’ – a history of ideas about how we experienced the world through our bodies.
Mind Hacks 
It’s interesting that the evil eye, as superstition, outlasted the science behind it by hundreds of years. Even in my childhood, European adults were blowing away the evil eye.
Philip Wrigley, owner of the Chicago Cubs baseball team, hired an “evil eye” in the 1930s to attend games and “put the whammy” on opposing teams.
The eye as transmitter is found worldwide, as is a prohibition against staring at people. Even in our society you don’t look directly at someone for any length of time without speaking. People in prison avoid eye contact since it’s seen as an aggressive act. Young children believe that the eye is a transmitter and that the eye beams of people can mix or clash. In the comics, Superman is able to heat a hotdog or open a safe with his eye beams. The eye objectifies, which is why we speak of “sex objects”. Not enough attention has been given to the way in which cultures train people to use their senses. In medieval times the dictum was “fides ex auditu” (faith comes from hearing) but by the Renaissance the Protestants were reading the Bible. Another medieval dictum was “nil intellectu quod non prius in aliquodo modo in sensibus”. There is nothing in the mind which is not first, in some manner, in the senses.