Comments on: The smell of white – mixtures of many distinct scents end up smelling the same

By: polistra

polistra — Fri, 23 Nov 2012 13:25:15 +0000

Quibble: White noise is not a hum, it’s a hiss. And it’s not rare in Nature, unless you consider wind to be rare.

I doubt that masking works with olfaction as it does with hearing. For instance, tobacco smoke is a very complex smell, including all the major categories of odor. It’s often considered to be ‘overwhelming’. Yet the best perfumiers were often heavy smokers.

By: Ed Yong

Ed Yong — Fri, 23 Nov 2012 01:41:17 +0000

@Johnny – It’s not sensory overload. From the paper:

“Our dilution procedure, in which all components were equated in magnitude with the least-intense component, rendered mixtures of overall low intensity. In other words, olfactory white was in no way overwhelming.”

By: Toos

Toos — Thu, 22 Nov 2012 19:08:40 +0000

johnny, I do know some about physics [like this about colors and light]. And appreciated it a lot, reading Ed’s post about this same kind of physics about smell. Though I don’t know that much about neurology, so I can’t – and therefore didn’t – tell anything about your point. But sure it could be of interest, especially with sources added as you did. So it’s not a denial! Just another field, as is for the discovery of Laurax [for which how the brain works with it, can stay a "black box"].

By: johnny

johnny — Thu, 22 Nov 2012 09:10:45 +0000

Thanks Toos, I’ll accept your paint vs. light explanation.
However, my main point was that the “white” smell phenomena observed may be the result of sensory overload and the difference between what the nose detects and the brain perceives, as is the case with the human eye, brain and vision. See David H Hubel, Eye, Brain, and Vision [Scientific American Library Series 1988]; and Hubel & Wiesel, Brain and Visual Perception [Oxford University Press 2005].

By: Toos

Toos — Thu, 22 Nov 2012 00:35:02 +0000

johnny, it looks like you are talking about mixing paint or alike. Which gives an opposite result to mixing light about which Ed is talking. The latter you can see happening on your screen, where white is the result of mixing all three basic colors of light, the only ones your pixels have. If you do the same with the 3 basic colors of paint, you get something completely different: the color you are talking about, mostly a kind of dirty-dark brownish. This is because your screen etcetera spreads light, while stuff like paint is absorbing it.

By: johnny

johnny — Wed, 21 Nov 2012 04:04:19 +0000

Perhaps the “white ” smell is caused by a sensory overload being placed on the human ofactory system as more scents are added. Thus, once overloaded, everything smells similar or the “same.” Add too many colors and everything turns black, not white. The scents don’t change, but the human ability to distinguish them is overwhelmed. Both the nose and brain are involved as the brain does not perceive “true” reality.

By: JIM

JIM — Tue, 20 Nov 2012 13:38:31 +0000

I think an apt analogy from the world of color is: colors created in one system can usually be matched with completely different materials from another system. For example, bring a cloth swatch from your furniture to your local hardware store to get matching paint. The color created with cloth substrate and dyes can be matched with a completely different system of paint base and tints. They key is, both systems have same-enough effect on the incoming light to present your eyes with an essentially identical stimulus. I wonder if the identical stimuli for the two smells happens at the sensor level (nose), or at the brain level, or somewhere in between?

By: jcm

jcm — Mon, 19 Nov 2012 21:21:12 +0000

The correct DOI is 10.1073/pnas.1208110109 . However, it loooks like is is not being resolved correctly. So here is the link to the paper: http://www.pnas.org/content/early/2012/11/15/1208110109

By: Chad Jones

Chad Jones — Mon, 19 Nov 2012 20:34:02 +0000

Great article. I wouldn’t have expected an “olfactory white” because, as you mentioned, most of the smells we identify as a single smell are actually complex chemical combinations (hmm…how to say that with less alliteration).