A caffè macchiato is basically nothing more than an espresso, or for the Viennese: a mocha, with a small amount of frothed milk. This is my standard order in the cafés in the San Francisco Bay Area. Whether it’s a latte, cappuccino, melange or macchiatone, it’s a shame if the milk is spoiled. Humans can immediately smell whether milk – or other food – is gone. But what about robots, which we hope will soon be serving us coffee? How will these artificial helpers recognize edible or spoiled food?
This brings us to the sense that has so far received little attention in robotics. Sight, touch, hearing – all senses that allow a robot to perceive and navigate its environment. But smell?
People Smell
It turns out that the sense of smell is more important for humans than we thought, even though many animals have a better developed sense of olfactory experience than humans. But we humans are also more influenced by smells than we think and would like to admit. Smell is very important for choosing a partner and can be influenced by hormonal fluctuations. People who seem to have an unpleasant odor are genetically too closely related to us, which is why we tend to exclude them when choosing a partner. If, yes, we were not deceived by external hormonal additives such as the contraceptive pill and made the wrong choice. The olfactory surprise when we stop taking the pill has ended many a relationship.
Capitalism has also recognized smell as an incentive to buy. I don’t mean in the form of perfumes or scented candles that are sold to people, but in the form of a mood enhancer in a business premises or house. Estate agents ask owners to bake cookies in the oven before viewings. The warm, sweet smell of fresh cookies immediately lifts the mood of prospective buyers and makes the property feel more homely. We’ve all fallen victim to this tactic when we think of the smell of fresh cookies wafting through train and subway stations. Stores have switched to baking industrially prepared dough on site. The resulting delicious smell attracts hurried commuters like light attracts moths.
I also sniff products myself. As soon as I receive books, especially illustrated books and tomes, I stick my nose into the pages and soak up the scent of ink and paper. I just don’t lick them – yet.
Animals Smell
Animals, on the other hand, can have such a strong sense of smell that we can use them for our own purposes. We have heard of sniffer dogs that can search for missing persons or fugitives or sniff out drugs in luggage at the airport. The truffle pig that can find that precious mushroom. Or cats and dogs that recognize COVID-infected people or cancer patients by smell. Or Oscar the cat, who lived at the Steere House Nursing and Rehabilitation Center in Providence, Rhode Island. Whenever the cat lay down on a patient’s bed in this hospice, the doctors and nurses would immediately call the relatives because death was imminent. Oscar, it is believed, was able to “sniff out” imminent death and keep the dying company in the last hours of their lives.
During a foot operation many years ago, my foot doctor also sniffed the sole of my foot to see if I had athlete’s foot or other diseases. In medical terms, smell is definitely a means of detecting illness for the medical profession too, and not just for Oscar.
Conversely, animals also smell. Dogs “dog”. Especially when dogs eat meat, as is normal for them. If the pet owners are vegans or vegetarians, they often also give their pets a low-meat or meat-free diet. The dogs then lose their typical dog smell, they no longer “dog”. Just like people, by the way. Vegans and vegetarians then prefer such meatless happy partners on dating apps, so that the body odor caused by meat consumption does not get in the way of the carnal pleasure of the lustful kind.
Robots Smell
If we now have new little helpers in our immediate living environment in the form of humanoid robots, then we should also talk about the sense of smell. On the one hand, we want robots to recognize spoiled food and dispose of it instead of serving it to us, or to recognize and remove vomit in an autonomous car, as well as dead rodents that may have crept in somewhere and then died and are now spreading a bestial smell.
However, machine olfaction is still in its infancy. Gas chromatographs or spectroscopic analyzers to identify volatile compounds are too slow, too large and bulky, too fragile and too expensive to serve as a practical artificial nose.
But smelling something is only one side of the coin. What about the smell of robots themselves? Aromas that are supposed to lift the mood in rooms are commonplace. And this also extends to mobile spaces, such as cars. Who isn’t familiar with the new car smell? It is mainly caused by the still evaporating adhesives and paints. The smell of fresh rain, which even has a name: petrichor.
But how do robots themselves actually smell? And is it important that they emit an odor themselves? At least that’s the opinion of automotive suppliers, who already offer installations for robotaxis that allow users to choose their own scent via an app, which is then emitted from aroma nozzles before entering the vehicle.
The new-robot smell, of plastic and metal, lubricating oil, adhesives and colorants is probably not one we want to smell in a living room or kitchen. Humanoid robots, which are a mixture of artificial intelligence, mechanical robot and organic tissue, should smell alive and pleasant to increase acceptance. However, this smell should not be overpowering, it should be subtle and less intrusive. And this odor threshold is different for each and every one of us.
After the personal computer (PC) and the personal digital assistant (PDA) now comes the personal humanoid robot (PHR). And it will be tailored to our individual needs in the same way that no smartphone today has exactly the same settings and apps as another. And that includes the smell of the personal robot.
In this new form of artificial life, functional scent and an artificial sense of smell will become increasingly important and very personal. Just as smell influences the choice of a partner, so too will the choice of our personal robot. The profession of the nose, as these highly talented perfumers are also known, is only now experiencing its heyday.