How people name sensations depends on those sensations’ salience

THE human sense of smell is weak. That is well known, and is suspected by many anthropologists of being the result of a trade-off in the primate brain in favour of visual processing power. In the specific case of people, however, the relative weakness of smell compared with sight extends to language, too. Humans have no difficulty putting names to colours but are notoriously bad at putting names to odours.

That might also be caused by how the brain is wired. But some doubt this. They suggest it is more likely a consequence of the tendency of languages to contain words useful to their speakers. Since smells matter little to most people, most languages have few abstract words for them. A study just published in Current Biology, by Asifa Majid at Radboud University in the Netherlands and Nicole Kruspe at Lund University in Sweden, supports this.

Dr Majid knew from previous work she had done that the Jahai, a group of hunter-gatherers who live in western Malaysia, are remarkably good at naming odours. For example, when she asked some Jahai, and also a comparable group of American volunteers, to name colours and odours they were presented with, the Americans generally agreed with one another when it came to naming colours but agreed much less when putting names to odours. When presented with cinnamon, for example, they described it variously as sweet, spicy, wine, candy, edible and potpourri. When presented with baby powder they offered vanilla, wax, baby oil, toilet paper, dentist office, hand lotion, rose and bubble gum as descriptions. Jahai answers, in contrast, were in equal agreement about both odours and colours.

When she published this result, Dr Majid suggested that it might, in part, be because the Jahai have a dozen words dedicated to describing different sorts of smells in the abstract (the equivalent of colour-words such as red, blue, black and white, of which there are generally reckoned to be 11 in English). For example, the Jahai use the word “cŋεs” for stinging sorts of smells associated with petrol, smoke and various insects, and “plʔeŋ” for bloody, fishy and meaty sorts of smells. According to Dr Majid, only “musty” is able to act in this way in English without drawing on analogy (banana-like, gooseberry-noted, and even earthy and sweet-smelling, are all analogies of some sort).

To test how important someone’s way of life is to his or her use of abstract words for smells, Dr Majid and Dr Kruspe looked at how two other groups of people from the Malay Peninsula used terms for colours and odours. These were the Semaq Beri, who also hunt and gather for a living, and the Semelai, who cultivate rice. Crucially, although these two peoples make their livings in different ways, their languages are closely related and they both live in the rainforest.

Dr Majid and Dr Kruspe asked 20 Semaq Beri and 21 Semelai to name odours and colours presented to them at random. The colours were on 80 differently hued cards; the odours on 16 variously scented sticks. The sticks were daubed with smells like (to English-speaking sensibilities) leather, orange, fish, garlic and turpentine.

The two researchers found that the Semaq Beri used abstract terms for odours 86% of the time—about as often as they did for colours, which was 80%. The Semelai also used abstract colour descriptions at a similar rate, namely 78% of the time. But when it came to describing odours they relied on abstraction on only 44% of occasions, while resorting to analogies, such as “banana” and “chocolate”, 56% of the time. Moreover, as with Dr Majid’s earlier study with the Jahai, the Semaq Beri more frequently agreed with one another about naming odours than did the Semelai.

Given these findings, Dr Majid and Dr Kruspe argue that it is the hunting-and-gathering way of life, rather than the use of a particular language, that is crucial to the use of abstract names for odours. Presumably, the business of surviving by eating what the forest has to offer requires a more discriminating use of the nostrils than is needed for farming.