The power of olfactory associations, or why I can never drink peppermint tea again

The readers of the BSR are an intelligent, forward-thinking crowd, so I know you will not think less of me if I admit that I don’t drink coffee. My hot beverage of choice comes from a leaf instead of a bean. That’s right, I’m a proud member of Team Tea.

I could talk about the virtues of tea all day. Just to name a few: reduced caffeine content means you can stay alert without getting jittery, you can grow your own at home, and there are a kajillion varieties (that’s a technical term). I and many other tea drinkers like to choose different teas to suit various moods or activities. For me, it’s usually black in the morning, green in the afternoon, and red or herbal at night.

Recently, I began to notice something very odd about my tea-drinking habit: I associate particular teas with whatever activity I was doing when I began drinking them. I’m not talking about a conscious association; rather, the smell and taste of the tea has the power to completely transport me to another time and place. For example, whenever I drink my favorite Rooibos tea, I am brought back to last summer when my boyfriend and I watched Buffy the Vampire Slayer on Netflix almost every night. The same thing is true for a wonderful Chai loose-leaf tea and the novel I was reading at the time, Hyperion. It’s an involuntary reflex. No matter what I’m doing or thinking in the moment, I can make a cup of tea and the past suddenly has an overwhelming presence in my mind, whether I like it or not.

In fact, I normally like it. It’s fun and a little trippy to be carried backwards in time to pleasant memories. It wasn’t until last week that I realized that this effect applies to unhappy memories as well. I made myself a cup of peppermint tea that I hadn’t had in several months, and before I knew it, I was mentally back at my desk this past spring, studying for my qualifying exam. For those of you who have been through a qual, you know that it is not an experience worth reliving (for those who haven’t, this gem from the PhD Comics archive sums it up quite nicely).

It turns out that this phenomenon is quite well-known, both to biologists and novelists. As Jonah Lehrer has pointed out, the power of taste and smell to evoke vivid memories has been known at least since the madeleine-flavored days of Marcel Proust. And recent findings by neuroscientists at the Weizmann Institute show that the olfactory associations have a special place in the brain, specifically the hippocampus. Apparently, when I drink peppermint tea (which of course is very fragrant, so I get the double whammy of taste and smell), my brain sends signals to remind me of the first time I drank it and the emotions I was experiencing at that time.

The link between our nose and our memory is a great quality for our species, evolutionarily speaking. Smells in our environment contain many signals about where to find food and how to avoid danger, so it’s to my advantage to remember them vividly. In a way, it’s ironic—I spent so many hours at my desk, drinking tea and trying to memorize equations. But in the end, the greatest impact on my brain was not made by reading articles (visual signals) or talking with labmates (auditory signals). It was the olfactory signals that made a lasting impression. If only I had a way to communicate physical chemistry concepts using smells, I’d be all set.

In case you’re wondering, here are the teas I mentioned. I urge you to make your own associations with them (preferably pleasant ones):

  • “Buffy the Vampire Slayer” tea: Safari Spice, from Celestial Seasonings
  • “Hyperion” tea: Chai Bengali Spice, from Baltimore Coffee & Tea
  • “Qualifying exam” tea: Peppermint, from Trader Joe’s

ResearchBlogging.orgYeshurun Y, Lapid H, Dudai Y, & Sobel N (2009). The privileged brain representation of first olfactory associations. Current biology : CB, 19 (21), 1869-74 PMID: 19896380

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  1. Matt Cavagnetto

    Looking at my old anatomy notes, I notice that the olfactory sense is the only one without a designated cortex in the cerebrum. Something like sound will be sent to the auditory cortex of the temporal lobe, visual information will be sent to visual cortex in the occipital lobe, etc. But smell is wired directly (via the olfactory nerve) to the hypothalamus, where some of the most complex, wide-ranging operations are controlled– things like rage, fear, pleasure, sex, sleep, etc. So it’s no wonder that smell should be so evocative. It’s got a direct hotline to a major center of our brains.

    Incidentally, I love a good cup of loose-leaf blackcurrant tea from Peet’s.