Just watched an amazing program on the relationship between the senses and how the brain processes information.
It appears that optical illusions are in fact beneficial to us and helps us survive. Even as they are illusions, they allow us to make sense (use it in a practical way) of sensory information.
This may be a hardwired genetic benefit. But it is also disconcerting as, even when we know what we are looking at, our brain may reject the “knowledge” and still be fooled by the image. It is physically unable to present us with conflicting results.
OTOH, it also allows us to “see” smells, sounds, touch. They showed a totally blind (lost sight a couple of months after he was born) cyclist who goes bike riding everyday on a narrow forest path. He uses sonar by clicking his tongue continuously and from the echos he forms an actual picture in his brain of the path. Tests showed that when he hears sounds his visual cortex is activated, even as he has no memories of actually ever seeing anything with his eyes.
We like to think that our senses are seperate and being processed distinct from each other. It appears now that we actually integrate all sensory information, though our visual input is the most influential sense, which may fool our taste or even our hearing.
Tests on culinary chefs proved that when fruit juices were presented to them but the colors were changed, these chefs had a real problem identifying the taste and definitively identify the taste of the fruit juice. One chef identified a yellow juice as apple juice, but in reality it was strawberry juice.
They also showed that sound has a great impact on our taste and touch perception. The same chefs were given a selection of potato chips and had to rate them for crunchiness. But while biting in the chips the sound of the crunch while biting and chewing were modified. It showed clearly that the lower the crunch sound, the more of the chefs rated those chips as very crunchy, even as they were chewing and feeling the crunch itself and the chip physically was not particularly crunchy.
It’s called neural plasticity and shows that the brain, while able to present us with an integrated “result” of our senses is physically (neural function) unable to present certain results which are not pertinent to our interaction with the environment per se.