Sniffler

It has been argued that good smells are in the nose of the sniffer, but a scientific study using a robotic "eNose" proves that pleasant smells are predictably universal. Still, your farts only smell good to you.

A group of Israeli neurobiologists were able to rank smells by pleasantness, by testing dozens of smells on people in Israel and Ethiopia in order to determine whether these good smells were universal or culturally specific.

"We tuned an eNose to human odor pleasantness estimates," they wrote. "We then used the eNose to predict the pleasantness of novel odorants, and tested these predictions in naïve subjects who had not participated in the tuning procedure. We found that our apparatus generated odorant pleasantness ratings with above 80% similarity to average human ratings, and with above 90% accuracy at discriminating between categorically pleasant or unpleasant odorants. Similar results were obtained in two cultures, native Israeli and native Ethiopian, without retuning of the apparatus."

The findings suggest that, unlike in sight and hearing, there is a systematic predictable link between stimulus structure and stimulus pleasantness in the realm of smell.

They added, "We could predict whether a person who we never tested before would like the odorant, and this prediction was consistent across Israeli and Ethiopian cultural backgrounds. We argue that this difference was not a reflection of better hardware, or better algorithms, but rather a reflection of a fundamental biological property of the sense of smell."

According to the test subjects, these were the best smells:

1. lime (fruit)
2. grapefruit (fruit)
3. bergamot (similar to an orange in scent)
4. orange (fruit)
5. peppermint

Rounding out the top 10 were freesia (flower), amyl acetate (a molecule that smells like apples and bananas), cassia (similar to cinnamon), mimosa (flowering tree), and fir (tree). The worst? The researchers say the smells consistently ranked the worst included "either carboxylic acids or amines [and] cyclohexanol." These would probably produce sharp, vinegary smells. Among the lowest-ranked of the so-called "pleasant" smells were musk and patchouli, though I don't know who finds hippie pleasant smelling.