I'm so greedy. Is it possible to smell the aroma while watching food videos?

Food is the eternal paradise for those who eat. When it’s time to eat, they turn on the food broadcasts with great energy, and even the takeaways seem to smell better. If the aroma of food can penetrate the screen, the experience will be instantly improved!

Nowadays, virtual reality (VR) technology can replicate the images, sounds and even touch of the real world, making the immersive experience more realistic. So, can I smell the aroma while watching food videos?

Incense box, the key to smelling

There are already many products trying to achieve an immersive olfactory experience, and the smell is mainly released by special fragrance boxes in the device.

For example, Scentee, after downloading the Scentee App, users also purchase a special device that can be connected to the phone, which has a built-in fragrance box. Plug the device into the earphone jack and click on the mobile app to make the device spray mist like a humidifier, emitting a specified smell. It can also be programmed to do more. When playing games, Scentee can emit the smell of gunpowder every time the player fires a weapon.

The device can spray mist like a humidifier丨Scentee

In order to make the smell smell more gentle, rather than spraying directly into the nostrils, virtual reality expert Jacki Morie has also developed a scent collar RemniSCENT. This collar also has a fixed fragrance box, a filter paper disc impregnated with scent, and a valve and fan on the top, both of which are opened and closed by a computer. When the user wears the collar, the collar can be wirelessly connected to the computer, and the output signal is transmitted to the valve and fan in conjunction with VR - when they are turned on, they can emit a scent near the user's nose.

Looks good, but the olfactory experience is not yet successful

There are many similar products, but they are rarely applied in real life. Why is smell still a missing link in VR experience? The most fundamental reason is that the reaction process between odor molecules and our olfactory system is very complex, making it very difficult to predict and simulate odors.

Gas molecules bind to olfactory receptors | Chen Qian

By superimposing the three primary colors on each other, you can create a variety of new colors, but it is much more difficult to combine various molecules into a specific smell. There are nearly 10,000 types of odor molecules that humans can detect, and slight changes in their molecular structure or concentration will change the olfactory perception. Some substances may have completely different smells despite having similar chemical formulas. For example, one of the lactones smells like mint, while another smells like mothballs.

In addition, there are many practical problems with the "fragrance box" product. For example, the odor molecules will remain in the air. If the previous odor has not dissipated, it will interfere with or even cover the new odor, greatly reducing the experience. At the same time, replacing a new fragrance box is expensive and troublesome.

Abandon the incense box and try inserting electrodes in your nostrils?

In order to circumvent some of the disadvantages of scent boxes, some scientists have developed a new idea: without the help of chemical substances, electrodes are inserted into the nasal cavity to directly stimulate the olfactory receptors through weak electric pulses to form a sense of smell.

Engineer Adrian Cheok conducted an experiment on this, and the results showed that some electrical stimulation is indeed related to the formation of smell. Under certain circumstances, subjects can produce smell-related sensations, such as fruity, minty, woody, etc. But at the same time, they also produce sensations unrelated to smell, such as pain, heat, pressure, numbness, etc.

Insert electrodes in the nose to sense smells | Adrian Cheok

Although the experiment preliminarily proved the feasibility of electrical stimulation to produce smell, the subjects experienced pain, visual flickering, and the number of odors they smelled was very limited. In addition, inserting electrodes into the nose also faces various safety and ethical issues, so ordinary people dare not try it easily.

During the COVID-19 pandemic, loss of smell was considered an important feature of COVID-19 infection, which made us realize that smell is an indispensable part of the senses. When the sense of smell disappears, the richness of our perception of things also decreases sharply. How to develop the olfactory experience and take the delicate level of perception to a higher level depends on the efforts of scientists!

References

[1]https://www.bbc.com/future/article/20210104-the-reason-why-you-cant-smell-television-shows-yet

[2]http://alltheseworldsllc.com/solutions/a-deep-inhale-scent-in-virtual-spaces/

[3]https://www.latimes.com/food/dailydish/la-dd-smartphone-smell-bacon-scentee-20131030-story.html

[4]Firestein, S. How the olfactory system makes sense of scents. Nature 413, 211–218 (2001).

[5]Morie J F. Meaning and emplacement in expressive immersive virtual environments[D]. University of East London, 2007.

[6] Chen Qian, Tang Zhi, Lai Chencen. The role and mechanism of olfactory receptors in non-olfactory tissues and cells[J]. Progress in Biochemistry and Biophysics, 2020(2):91-104.

[7]Cheok AD, Karunanayaka K. Digital Smell Interface[M]//Virtual Taste and Smell Technologies for Multisensory Internet and Virtual Reality. Springer, Cham, 2018: 93-117.

Author: Yaxie

Editor: Yi Yin, Window Knocking Rain