To smell the world — Including the sense of smell in Virtual Reality
In the last decade, Virtual Reality has been quickly growing in terms of quality of immersion and cost. All of us would have played or seen someone play a VR game. The use of VR technology has been rapidly moving to a lot of other domains such as education, therapy, and medicinal and military training. This is mainly because of the immersive experience that VR can provide.
When you hear about advancements in this field, you only think of the sense of touch and motion being included. It isn’t very often that we think of the sense of smell.
Although a handful of attempts have been made to simulate the sense of smell, none of them have been given much spotlight.One of the most noted of these, Feelreal, has successfully created a VR device that includes over 255 different smells, which can also be combined to create more smells.
But the sense of smell is still greatly undervalued. According to a study¹ by McCann Truth Central, around 50% of the younger generation were ready to give up their sense of smell to keep their phones, cars, and passports.
But anosmics (people who cannot smell) will tell you otherwise. They will tell you how important smell is to us. Other than the challenges regarding hygiene and food, anosmics also are reported to be 5% more depressed² than people who can smell.
So, why is the sense of smell not talked about as often in the field of VR? Before we answer this, let us understand what smell is.
What is smell?
The roof of our nose has a bunch of odor receptors³. Humans have around 400 types of odor receptors, each of which only get triggered by certain molecules. Every time you inhale, there are a wide range of molecules that go into your nostrils, and simply put, your receptors and brain tell you what smell that is.
But what’s the purpose of doing this, you may think.
It turns out that it’s for the simple purpose of remembering what’s good for us and what’s not. The olfactory(that’s just a fancy word for smell) nerve directly connects to your amygdala and hippocampus, which are parts of the brain that are associated with emotion and long term memory. Smell is the only sense that is directly connected to the amygdala.
Ever wondered why you can smell certain places you’ve been to over ten years ago? This is why that happens. This is also why you’re craving for that delicious pizza during the lockdown, and why the picture below made you think of an smell you’ve experienced.
This sense is also genetic. One study⁴ found that people with different olfactory receptor genes had different responses to the same smell. This explains why sometimes we smell certain things while our friends can’t.
Extrapolating on this topic, this is why different animals have different senses of smell. We like the smell of baked potatoes because they are nutritionally very valuable to our bodies (though not in excess either). Sharks can smell blood from a large distance. Mosquitoes are able to find humans because they are able to smell the CO2 that we exhale, and our bodily odours⁵.
So, if we know all of this, what’s holding us back?
Most of our other senses like sight, sound, touch, balance, or temperature, are all physical elements of the world, which we are perceiving. Smell, on the other hand, is perceived because of experience, either our own, or our forefathers’. This makes it harder to understand.
There are also a limitless number of things that we could possibly smell. Even if we were to use a select few of these for our simulation, we would need to have a way to remove this smell from the real world when it’s no longer present in the simulation.
Moreover, different people respond differently to odours. If your character is in a burning hospital (which isn’t that uncommon in games), you would be surrounded by the smell of smoke and blood. This could trigger an allergic or traumatic response from certain people. This poses a huge challenge to anyone aiming to simulate smells in VR.
The Conclusion
Although it is certain that our sense of smell is key to our perspective of the world and all the things in it, the lack of knowledge and mainstream attention has blocked the path to the inclusion of smell in Virtual Reality. But perhaps, once the technological community has improved the simulation of the other senses, the spotlight will shift to smell and how it would make immersions more empathetic and immersive.
[1]: McCann Worldgroup: Truth About Youth, https://www.scribd.com/doc/56263899/McCann-Worldgroup-Truth-About-Youth
[2]: Steve Van Toller, Assessing the Impact of Anosmia: Review of a Questionnaire’s Findings, Chemical Senses, Volume 24, Issue 6, December 1999, Pages 705–712, https://doi.org/10.1093/chemse/24.6.705
[3]: Rinaldi A. (2007). The scent of life. The exquisite complexity of the sense of smell in animals and humans. EMBO reports, 8(7), 629–633. https://doi.org/10.1038/sj.embor.7401029
[4]: Monell Chemical Senses Center. (2019, April 30). Do you smell what I smell? From genes to receptors to perception: Olfaction unraveled. ScienceDaily. Retrieved September 15, 2020 from www.sciencedaily.com/releases/2019/04/190430164208.htm
[5]: Carol Torgan, Ph.D. : How Mosquitoes Detect People https://www.nih.gov/news-events/nih-research-matters/how-mosquitoes-detect-people#.X2Db_YJ0tqw.twitter
