A blog about senses.
Doesn’t that look good? It was a meal I ordered in Port Hardy a few years ago. It looked good, and it tasted good. To determine that, you would use four of your five senses. We mostly take our senses for granted as we grow up. Once in a while I have given some thought in passing about how much more difficult life would be if I lost my sight or hearing, of course. Usually when I am made aware of people less fortunate than myself, but for the most part I simply didn’t give my senses any thought at all. Humans are incredibly adaptable, and there appears to be a significant amount of flexibility our dependence on our different sensory modes to perceive our surroundings. One of the most fascinating examples is the use of echolocation by the American Daniel Kish, who has been blind since the age of 13 months. He not only detects objects around him, but he can describe them in surprising detail using tongue clicking in a manner similar to bats. Similarly, Brian Bushwaywas able to describe an abstract sculpture using the same technique . Bushway lost his vision at the age of 13, but was taught how to use sound by Kish. By the age of 16 he had mastered the technique. Learn more about the work of Kish and Bushway at Visioneers .
I have no such abilities, and in my case the senses that inspired me to write this are smell (olfaction) and hearing (audition). Well, like most aging people my sight is also weaker than it used to be, but with corrective lenses that is less of a problem. The sense of smell is easy enough to understand, although it is often confounded with the sense of taste (gustation), which together give food its flavour. The sense of taste is limited to sensing saltiness, sweetness, bitterness, sourness, and umami (savoriness). Umami has been added since when I learned about taste many moons ago. In practice, what we tend to think of as taste is a combination of taste and smell, however. Both my maternal grandmother and my mother lost their sense
of smell. In my mother’s case this happened when she fell off a ladder onto a concrete floor when she was about 55 years old. Thus she lived without a sense of smell for 33 years, about 20 of those years on her own. I lost my sense of smell gradually in my 40’s and 50’s, likely as a result of numerous sinus infections, which were bad enough to require surgical intervention (the details of which I will spare you from). Under normal circumstances my lack of the sense of smell does not affect me other than making food less flavourful, so I prefer food that relies more on taste than on smell. On the positive side it allows me to drink cheap wine (plonk) with no major loss of enjoyment as long as the wine is not too acidic. On the other hand, I have to rely on people around to detect if I stepped in dog pooh, while they in turn need not fear any comments by me about any odour they might produce. My defective olfactory system has some potential serious consequences, however. For example, I am unable to smell food that is off, smoke, gas or anything else that one might wish to avoid. For example, some of the field work I did around Prince George, BC, when I was working was in grizzly bear country. At one time my research technician alerted me to a bad smell at a site where we wanted to check some insect traps we had set out a month or so earlier. The stench, which I was completely oblivious to, indicated to us the potential presence of a dead animal, which could have been a carcass cached by a bear. You do not want to stumble across the remains of a grizzly bear kill given that the owner may be nearby, so we opted to come back another day! Closer to home, I would be unable to detect a natural gas leak or burning food on the stove or in the oven (until the smoke alarm goes off). Unfortunately for me, you cannot echo locate smell, so my only option is to adapt.
My other deficiency is a slight loss of hearing. If you met me, you would likely not notice, since I probably would seem to hear just fine, or at least as well as other men in their early 70’s (although my wife may have a different view of how good my hearing is). This problem has appeared in the past few years, and is only a problem when I engage in one of my favourite hobbies, bird watching. The problem is that I have lost the ability to hear high very frequencies, but only in my left ear. Thus, when I hear birds like Golden-crowned Kinglets or Brown Creepers I can’t determine where the sound is coming from. If you were to watch me in this situation, you would see me spinning around like a top, because no matter which way I turn, the sound is always coming from the right. That makes locating the birds (which are hard enough to spot anyway) more or less impossible unless I happen to see movement somewhere in the trees or bushes.
My point is that we should be grateful for the senses we have. Humans primarily rely on sight, but our other senses are extremely important, and we should make use of them while we can. In the case of Daniel Kish and Brian Bushway, studies have shown that the part of the brain in sighted individuals that interprets visual input has adapted to interpret the auditory input to provide an image, albeit a relatively coarse one (Thaler et al. 2011). This shows that we are capable of enhancing our sensory abilities, at least in some cases.
Thaler L, Arnott SR, Goodale MA. 2011. Neural correlates of natural human echolocation in early and late blind echolocation experts. PLoS one 25;6(5):e20162.