Posts Categorized: Science

How many artworks have you seen that’s made for the sense of smell? (The ‘nose’ of a wine or Chanel No. 5
doesn’t count).

But it’s official, backed by hard science: our olfactory sense can distinguish a minimum of one trillion different odors. Okay, they did not test one trillion odorants but used a complex mixture of up to 128 distinct odors in various combinations for the subjects to tell the difference; and by statistical techniques worked out the possible permutations. See report in Howard Hughes Medical Institute (HHMI) website.

By comparison, our eyes can distinguish only up to 10 million different colors and shades, from merely three types of color sensitive neurons: for red, blue or green. It is not surprising then the enormity of our sense of smell: there are 400 different kinds of smell receptor neurons in our nose epithelium which is the size of a postage stamp! Think of the combinations and permutations—possibly far more than one trillion.

If our nose can tell us so much more about our environment, why can’t it become the source of art? Simply, it’s a case of too much unmediated information.

First, the connection problem: our sensory neurons in the nose send messages directly to the brain, including a short cut to its emotional center, the amygdala, initially bypassing the thalamus (associated with consciousness – thinking and memory)—in contrast to all other senses. The messages from the retina of our eyes, for example, enter the thalamus first before proceeding to the visual cortex for analysis: form, color, contrast and movement. After that, the visual information is sent to different parts of the brain via two separate pathways: dorsal and ventral streams, which we now believe to be important in our learning. The dorsal  stream is known as the ‘where & how’ pathway and the ventral stream the  ‘what’ pathway.  The ‘where & how’ path deals with object location in relation to the viewer (ego-centric), important for planning action (how to grab that banana). The ‘what’ path connects to parts of the cortex which identify and name objects, and place them in relation to others (allo-centric)—allowing us to see things in wider context.

So, the sense of smell is more direct, more primitive, without much analysis or meddling from our thinking brain. See my post on how our eyes often deceive us because of this meddling from formed memory, seeing only what you expect to see.

We smell a lot more than we are aware and so it can drive our behavior surreptitiously. For example, there’s the case of ‘strip club science’ where scientists found that female strippers get more tip when they are ovulating because their bodies emit certain scents! Olfaction is more closely tied to our day-to-day survival and procreation. A blind mouse can live a more or less normal life but losing the sense of smell would kill it—no food or sex. Humans who lose the sense of smell can compensate by observing and learning from others.

Why is it so? The answer lies in the function each sense serves in our struggle to survive—how each helps us predict the future and minimize uncertainty.

Of our five senses, the first three are direct contact– touch, taste and smell. Smell however can sense somewhat distant odors: it receives molecules that are volatile and can travel through the air. This is an advantage since the animal can tell something is happening before it gets too close. The other two we all know well. Hearing can sense a bit farther distance than smell; and sight even farther. Good eyesight has huge survival value—knowing well ahead allows for better planning. And our visual system allows for plenty of planning, practically involving our whole body-brain.* Art emerges along the way—frequently when planning goes awry because of our memory distortions.

The next question is, based on this biological and evolutionary fact, how do the two art forms, art and music compare? Which is more immediate, with shorter connection to and less meddling from the thinking brain? I hope to do a future post on this but it’s daunting.

 *  Fully 30% of neurons in our cerebral cortex process information from the eyes, vs 8% for touch, and 3% for hearing—and almost negligible for smell, which can sense such a large number of odorants. Apparently, receiving information doesn’t take much brain power, it’s the analysis that does.

NEWS & UPDATES

2/16/2016   Regarding the function of the thalamus in our olfactory system, recent research has found neurons in the thalamus that are involved in olfactory attention and learning but details are still scarce. It remains true that olfactory input  from the nose first goes to many parts of the brain, including the amygdala (emotional center) before entering the thalamus (associated with consciousness), and in contrast to other senses.