"SMOUND" PROPOSITION: What you hear may affect what you smell.
Image: Peter Sherrard/Getty Images
Editor's note: This story, from the April 2010 issue, is being posted early to coincide with a journal publication date.
Flavor just got some competition. Smell and taste are known to converge to produce the best and worst of culinary experiences, but new research suggests that information received through the nose can also be altered by noise. If confirmed, this newfound union could have potent olfactory and gustatory implications.
The discovery of a possible smell-sound sense, or “smound,” came to Daniel Wesson by accident. “I was simply trying to find the way the olfactory tubercle responds to odors,” he says, referring to a structure at the base of the brain that was implicated in odor detection only in 2004. But when he set down his coffee mug on a laboratory bench one afternoon, he noticed that the activity in the tubercle of the mice he was studying spiked. He picked his mug back up. Sip. Clunk. Spike.
Wesson and his colleague Donald Wilson, both at the Nathan S. Kline Institute for Psychiatric Research in Orangeburg, N.Y., decided to investigate the smound spikes more rigorously. As they describe in the February 24 Journal of Neuroscience, they first verified that the tubercle does indeed respond to smell. They found that 65 percent of tubercle cells from 23 anesthetized mice were activated by at least one of five odors—an important finding in its own, because no one knew if tubercle cells could discriminate odors, a process thought to be exclusive to the part of the brain known as the piriform cortex. Next, Wesson and Wilson repeated the experiment, this time presenting a subset of the cells with only a tone: 19 percent fired.
The next set of recordings “really changes the way we think about smell,” Wesson says. He and Wilson repeatedly sent a mix of both odors and tones into tubercle cells and saw that responses from 29 percent became either enhanced or suppressed depending on the presence or absence of the second stimulus. One cell, for example, appeared not to care for either smell or sound but responded robustly to the combination.
Historical hints of perceptual interplay between smells and sounds have been reported— in the mid-1800s French perfumerist G. W. Septimus Piesse catalogued odors based on analogous auditory pitches. Wesson and Wilson, though, may have found the first neural evidence. But because sensory activity does not always equate with perceived changes, they must devise an experiment to determine what their mice actually smell and hear. The perceptual shift could be significant: changes in sensory activity even smaller than what was seen in these experiments can greatly influence the senses. “In theory, one spike could allow for the discrimination between a tangerine and a mango,” Wesson notes.
Olfactory-auditory integration adds to a growing list of intimate connections between sensory systems. “While we like to think that there are five separate senses, that’s not the way it works,” remarks Donald Katz, a neurobiologist at Brandeis University. “What your brain really does is take objects and process them.”
The existence of a smound sense has broad implications. It may help elucidate the defective processing behind mysterious disorders such as synesthesia, in which patients taste colors and see flavors. And Wesson and Wilson plan to develop technology related to their findings; for instance, they hope to patent a device that emits a tone into the ear of a dog every time it sniffs, enhancing its sensitivity to, say, explosives. The necessary details will come after they identify which frequencies and intensities best amplify and suppress odors.
Of course, diners can experiment on themselves. They could see if food smells— and hence, tastes—differently based on the background sounds. You might find that your saffron risotto pairs better with Beyoncé than with Beethoven.
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19 Comments
Add CommentOne could guess from this result that animals may respond differently to odors, depending on sonic stimuli, and/or vice versa. It’d be most interesting to identify actual behavioral evidence in animals. For this association to exist it seems that some real advantage is likely gained, if only to not stop to smell the roses if a tree is falling…
Reply | Report Abuse | Link to thissuch a surprising finding, though I sometimes have such kind of feeling
Reply | Report Abuse | Link to thisI've seen reports of subjects under the influence of psychedelic drugs hearing colors. Does this open a new field of the connectedness of all the senses when all the channels are 'way' open?
Reply | Report Abuse | Link to thisAs a synaesthete I object to the descriptions of synaesthesia in this article as "defective processing" and a "disorder". I am sure I would not be the only synaesthete to find such descriptions offensive.
Reply | Report Abuse | Link to thisAs a synaesthete I object to the descriptions of synaesthesia in this article as "defective processing" and a "disorder". I am sure I would not be the only synaesthete to find such descriptions offensive.
Reply | Report Abuse | Link to thisAs the article states in a single sentence: “But because sensory activity does not always equate with perceived changes, they must devise an experiment to determine what their mice actually smell and hear.”
Reply | Report Abuse | Link to thisThese experiments only established a cellular level neural response to stimuli, not any perception of smell or sound. All the references this article made to perceptions and synesthesia were highly speculative and premature.
This actually makes a lot of sense to me from an evolutionary perspective. Being able to differentiate between the smell of a predator that is old -- and is thus just a smell -- and the smell of a predator closing in on you -- thus combined with the particular sounds of that predator moving through the environment -- would be critical for animals.
Reply | Report Abuse | Link to thisAs a side note, I also find the description of synaesthesia as a disorder to be inaccurate. I am a synaesthete, and what is described in this article as a disorder is, for me and others like me, a skill and ability that we benefit from constantly. The word "disorder" implies that it is a negative condition that should be fixed, which in this case is about as far from the truth as you could get.
I am fascinated by synaesthesia. I often wondered if you viewed it as an impediment or an advantage. Good to know!! Great comment btw violetlorien.
Reply | Report Abuse | Link to thisThis reminds me of a study of how vocalizing a word while using a lip movement that resembles a similar will make the person misshear the word said.
Reply | Report Abuse | Link to thisLike a video would show someone motioning his lips as saying Hand would say Head. Those weren't the actual words used for research.. i'm just making those up to give you an idea.
Anyways, i wonder if there's a connection.
This reminds me of a study of how vocalizing a word while using a lip movement that resembles a similar word will make the person misshear the actual word that was enunciated.
Reply | Report Abuse | Link to thisLike a video would show someone motioning his lips as saying Hand but the sound bite sent to the viewer would be Head. Those weren't the actual words used for research.. i'm just making those up to give you an idea.
Anyways, i wonder if there's a connection. Its pretty similar.
RWS-GR , Thing you have heard of synesthesia
Reply | Report Abuse | Link to thisIt is disturbing that Scientific American would call synesthesia a disorder. Synesthesia is not debilitating and counts many superior creatives in its ranks as well as people with better memory skills than average. I'm an author at work on a book about synesthesia and would like to point out that successful people from Marilyn Monroe, to Itzhak Perlman, Billy Joel and Pharrell Williams all had/have it and have done quite well. Further, meditative adepts like Tibetan and Zen monks experience it at very high rates and old Buddhist teachings allude to it being present in enlightenment.
Reply | Report Abuse | Link to thisthat one British savant said he sees numbers as shapes as he calculates massive formulas; and many musicians with perfect pitch describe sound as having color...obviously the more 'open the channels' between senses the better, no?
Reply | Report Abuse | Link to thisI didn't know that! I need to keep that in mind while I'm cooking.
Reply | Report Abuse | Link to thisI agree with LQ: synaestehetes have an uncommon perception I think superior: that involves all senses at one time.
Reply | Report Abuse | Link to thisI had an automotive Battery explode next to me about 3 years ago. since then my sence of smell and tast have deteriated severly. I now ware hearing aids in both ears. But the hearing aids do not enhance any other sences.
Reply | Report Abuse | Link to thisI did not have any acid contact as I was protected by the generator motor from the battery.
after the explosion I was completely deaf for about 6 hours and then started hearing murmers recovery took about two days but about 50% still missing at all frequencies.
Oliver Sacks, M.D. a british neurologist has done a lot of work on this subject. he has some new books out on music and neurology but the classic is "the man who mistook his wife for a hat"
Reply | Report Abuse | Link to thisWhat is it if not a disorder?
Reply | Report Abuse | Link to thisNabokov had it with words and colors. Very helpful to the creative process
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