Unlocking the Mysterious Connection Between Taste, Smell, and Memory

Question: Why are taste and smell so closely linked with our memory?

Stuart Firestein: The connection between taste, smell and memory is a very curious one. It’s well documented. We’ve all had the experience. There are interesting quirky things about it. Why there is such a connection or how it exactly works is not so well known, but we get hints from the nature of it.

So we’ve all had the experience of course, this so called "Proustian" experience. You know there is a famous passage in Marcel Proust’s "Remembrance of Things Past" in which he tastes a Madeline cookie and a sip of lemon tea and this vivid memory from 40 years earlier, from his childhood 40 years earlier—coming home from church and having this lemon tea and a Madeline cookie at his aunt’s house—just comes back to him and perfectly vivid, as if it were right there in front of him and he writes several pages about that and then goes onto write what, 40 volumes or some crazy thing, about 7 volumes I think it actually is of memory, of memories. So that’s maybe the extreme example, but we’ve all had that experience where we smell something or we taste something and some memory quite vivid comes back, usually from quite some time ago.

Now one of the things we can note about those memories is they’re always emotionally laden somehow or another. You don’t smell something and remember a page of text or an equation or a phone number or something useful like that. You always remember something like grandma’s living room, the first day of school. You know one of the most recognizable smells in America is the smell of crayons, Crayola crayons. So you know that brings right back, you can imagine that smell and you’re right back in school somehow or another. So it’s always something emotional, your first lover or some event like that. So that is one important thing about it. It seems to have an emotional content rather than an informational content if you will, for these memories.

The other is that they are long-lasting. We recall things from many, many years ago and they’re extremely vivid. Now the ones that involve taste—which I remind you again also involve olfaction really—we call them taste aversions because you have the sense that it’s taste and it’s in your mouth, but this is just a trick by the way, your brain is playing on you. If you’ve done the jelly bean experiment you’ll know that the flavor is due to your olfactory system and yet the experience of flavor is unquestionably still in your mouth. This is just some little trick your brain plays on you because it thinks that is where it should taste things. So we call them taste aversions. These are very interesting and we’ve all had this experience too. We eat some food. A few hours later we get sick from it and that’s it. We just can’t even think about eating it again. This is also very, very interesting kind of learning, which is very uncommon.

For one, it’s one-trial learning. You eat something. You get sick from it. You’re done with it. It lasts for an extremely long time, typically years, sometimes the rest of your life. You just don’t want anything to do with whatever it was that made you sick, peanut butter or lobster or whatever it was you know. And most remarkably this memory can be formed with several hours of delay, which is very uncommon. Usually in order to make... and this works for other animals well, not just people. You can induce a taste aversion in a mouse or a rat or a dog or anything. They get them normally, but you can also induce them. And you can do them with hours of delay, so you can taste the food. You can eat the food and then you get sick on it four or five, six hours later and that’s... You could have even eaten things in between that and it doesn’t matter. Your aversion will be to what you tasted then that made you sick. And as I say that is true for other animals as well, so it’s one-trial learning. It’s extremely long-lasting. It’s a very stable, intense memory and it can be formed with significant delay in it.

There is a great instance of this I have to say. A researcher named John Garcia I believe is his name. Several years ago he was... I forget where he was, but at some university in I believe California, in any case in the West. And there was a problem with coyotes predating on sheep, so sheep farmers were up in arms. The coyotes were killing off their sheep and they wanted to go out and shoot all the coyotes, which would have also been a bad idea because it’s part of a whole ecosystem, et cetera, et cetera. So Garcia came up with this idea that maybe he could get the coyotes to leave the sheep alone and he did it by using taste aversion, so he took a few sheep carcasses, dead sheep and he laced them with a chemical called lithium chloride. Now if you eat something with lithium chloride in it you will get dreadfully ill. You’ll get terribly sick, miserable nausea and all the rest of that, but you will not die from it and so these coyote
would come and eat these sheep. Then they’d go back to their burrow and they would spend a miserable night being sick from the sheep and that was it. They just didn’t want anything to do with sheep after that and you had these coyotes that just they’d find something else to eat, whatever it was. I’ll go kill something else, but I’m not messing with sheep anymore, so it was effective actually.

Recorded September 22, 2010
Interviewed by Andrew Dermont

The cause of the so-called "Proustian experience" of recalling a vivid memory through taste is well documented, but its cause continues to confound scientists.

Scientists find a horrible new way cocaine can damage your brain

Swiss researchers identify new dangers of modern cocaine.

Getty Images
Mind & Brain
  • Cocaine cut with anti-worming adulterant levamisole may cause brain damage.
  • Levamisole can thin out the prefrontal cortex and affect cognitive skills.
  • Government health programs should encourage testing of cocaine for purity.
Keep reading Show less

Bespoke suicide pods now available for death in style

Sarco assisted suicide pods come in three different styles, and allow you to die quickly and painlessly. They're even quite beautiful to look at.

The Sarco assisted suicide pod
Technology & Innovation

Death: it happens to everyone (except, apparently, Keanu Reeves). But while the impoverished and lower-class people of the world die in the same ol' ways—cancer, heart disease, and so forth—the upper classes can choose hip and cool new ways to die. Now, there's an assisted-suicide pod so chic and so stylin' that peeps (young people still say peeps, right?) are calling it the "Tesla" of death... it's called... the Sarco! 

Keep reading Show less
Politics & Current Affairs

Political division is nothing new. Throughout American history there have been numerous flare ups in which the political arena was more than just tense but incideniary. In a letter addressed to William Hamilton in 1800, Thomas Jefferson once lamented about how an emotional fervor had swept over the populace in regards to a certain political issue at the time. It disturbed him greatly to see how these political issues seemed to seep into every area of life and even affect people's interpersonal relationships. At one point in the letter he states:

"I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend."

Today, we Americans find ourselves in a similar situation, with our political environment even more splintered due to a number of factors. The advent of mass digital media, siloed identity-driven political groups, and a societal lack of understanding of basic discursive fundamentals all contribute to the problem.

Civil discourse has fallen to an all time low.

The question that the American populace needs to ask itself now is: how do we fix it?


Discursive fundamentals need to be taught to preserve free expression

In a 2017 Free Speech and Tolerance Survey by Cato, it was found that 71% of Americans believe that political correctness had silenced important discussions necessary to our society. Many have pointed to draconian university policies regarding political correctness as a contributing factor to this phenomenon.

It's a great irony that, colleges, once true bastions of free-speech, counterculture and progressiveness, have now devolved into reactionary tribal politics.

Many years ago, one could count on the fact that universities would be the first places where you could espouse and debate any controversial idea without consequence. The decline of staple subjects that deal with the wisdom of the ancients, historical reference points, and civic discourse could be to blame for this exaggerated partisanship boiling on campuses.

Young people seeking an education are given a disservice when fed biased ideology, even if such ideology is presented with the best of intentions. Politics are but one small sliver for society and the human condition at large. Universities would do well to instead teach the principles of healthy discourse and engagement across the ideological spectrum.

The fundamentals of logic, debate and the rich artistic heritage of western civilization need to be the central focus of an education. They help to create a well-rounded citizen that can deal with controversial political issues.

It has been found that in the abstract, college students generally support and endorse the first amendment, but there's a catch when it comes to actually practicing it. This was explored in a Gallup survey titled: Free Expression on Campus: What college students think about First amendment issues.

In their findings the authors state:

"The vast majority say free speech is important to democracy and favor an open learning environment that promotes the airing of a wide variety of ideas. However, the actions of some students in recent years — from milder actions such as claiming to be threatened by messages written in chalk promoting Trump's candidacy to the most extreme acts of engaging in violence to stop attempted speeches — raise issues of just how committed college students are to
upholding First Amendment ideals.

Most college students do not condone more aggressive actions to squelch speech, like violence and shouting down speakers, although there are some who do. However, students do support many policies or actions that place limits on speech, including free speech zones, speech codes and campus prohibitions on hate speech, suggesting that their commitment to free speech has limits. As one example, barely a majority think handing out literature on controversial issues is "always acceptable."

With this in mind, the problems seen on college campuses are also being seen on a whole through other pockets of society and regular everyday civic discourse. Look no further than the dreaded and cliche prospect of political discussion at Thanksgiving dinner.

Talking politics at Thanksgiving dinner

As a result of this increased tribalization of views, it's becoming increasingly more difficult to engage in polite conversation with people possessing opposing viewpoints. The authors of a recent Hidden Tribes study broke down the political "tribes" in which many find themselves in:

  • Progressive Activists: younger, highly engaged, secular, cosmopolitan, angry.
  • Traditional Liberals: older, retired, open to compromise, rational, cautious.
  • Passive Liberals: unhappy, insecure, distrustful, disillusioned.
  • Politically Disengaged: young, low income, distrustful, detached, patriotic, conspiratorial
  • Moderates: engaged, civic-minded, middle-of-the-road, pessimistic, Protestant.
  • Traditional Conservatives: religious, middle class, patriotic, moralistic.
  • Devoted Conservatives: white, retired, highly engaged, uncompromising,
    Patriotic.

Understanding these different viewpoints and the hidden tribes we may belong to will be essential in having conversations with those we disagree with. This might just come to a head when it's Thanksgiving and you have a mix of many different personalities, ages, and viewpoints.

It's interesting to note the authors found that:

"Tribe membership shows strong reliability in predicting views across different political topics."

You'll find that depending on what group you identify with, that nearly 100 percent of the time you'll believe in the same way the rest of your group constituents do.

Here are some statistics on differing viewpoints according to political party:

  • 51% of staunch liberals say it's "morally acceptable" to punch Nazis.
  • 53% of Republicans favor stripping U.S. citizenship from people who burn the American flag.
  • 51% of Democrats support a law that requires Americans use transgender people's preferred gender pronouns.
  • 65% of Republicans say NFL players should be fired if they refuse to stand for the anthem.
  • 58% of Democrats say employers should punish employees for offensive Facebook posts.
  • 47% of Republicans favor bans on building new mosques.

Understanding the fact that tribal membership indicates what you believe, can help you return to the fundamentals for proper political engagement

Here are some guidelines for civic discourse that might come in handy:

  • Avoid logical fallacies. Essentially at the core, a logical fallacy is anything that detracts from the debate and seeks to attack the person rather than the idea and stray from the topic at hand.
  • Practice inclusion and listen to who you're speaking to.
  • Have the idea that there is nothing out of bounds for inquiry or conversation once you get down to an even stronger or new perspective of whatever you were discussing.
  • Keep in mind the maxim of : Do not listen with the intent to reply. But with the intent to understand.
  • We're not trying to proselytize nor shout others down with our rhetoric, but come to understand one another again.
  • If we're tied too closely to some in-group we no longer become an individual but a clone of someone else's ideology.

Civic discourse in the divisive age

Debate and civic discourse is inherently messy. Add into the mix an ignorance of history, rabid politicization and debased political discourse, you can see that it will be very difficult in mending this discursive staple of a functional civilization.

There is still hope that this great divide can be mended, because it has to be. The Hidden Tribes authors at one point state:

"In the era of social media and partisan news outlets, America's differences have become
dangerously tribal, fueled by a culture of outrage and taking offense. For the combatants,
the other side can no longer be tolerated, and no price is too high to defeat them.
These tensions are poisoning personal relationships, consuming our politics and
putting our democracy in peril.


Once a country has become tribalized, debates about contested issues from
immigration and trade to economic management, climate change and national security,
become shaped by larger tribal identities. Policy debate gives way to tribal conflicts.
Polarization and tribalism are self-reinforcing and will likely continue to accelerate.
The work of rebuilding our fragmented society needs to start now. It extends from
re-connecting people across the lines of division in local communities all the way to
building a renewed sense of national identity: a bigger story of us."

We need to start teaching people how to approach subjects from less of an emotional or baseless educational bias or identity, especially in the event that the subject matter could be construed to be controversial or uncomfortable.

This will be the beginning of a new era of understanding, inclusion and the defeat of regressive philosophies that threaten the core of our nation and civilization.