The nose knows

The first few years my wife and I were married, we had a dog named Doolin.

At least I think Doolin was a dog.  The story is that she was born to the unholy union between a border collie and a bluetick coonhound, but there's credible evidence she was an alien infiltrator from the planet K-9, sent to study humans by pretending to be a humble house pet.  My observations suggested that she was far smarter than humans but had only recently mastered pretending to be a dog.  She is, far and away, the weirdest dog I've ever met, and I've had dogs pretty much my whole life.  She figured out how to unlatch our gates (and let herself out) by watching us; we ultimately had to put carabiners on the latches to stop her from going on walkies by herself.  She valiantly attempted to herd our four cats, an effort that was ultimately unsuccessful.  Of her many odd habits, one of the funniest was that she was never without her favorite toy, a plush jack that she carried around in her mouth -- always pointing the same way.  (We tested this by taking it from her and sticking it in her mouth the other way 'round.  She dropped it, looked at us as if we'd lost our minds, and picked it up from the other direction.)

Doolin, with her jack toy sticking out of the right side of her mouth, as it obviously should be

One of Doolin's most curious traits was an extraordinary sensitivity to us, particularly to Carol.  She seemed to watch us continuously for cues about what was going on, and sensed when one of us was upset or feeling unwell.  Most strikingly, Doolin always knew when Carol was about to get a migraine.  Starting about a half-hour before the symptoms began, Doolin followed Carol around like her shadow, and if Carol sat down, Doolin smushed herself right up against her.  It got to be that Carol knew when to prep for a migraine once she saw Doolin acting weird (well, weirder than usual, which was admittedly a pretty high bar).

I used to think that people claiming their dogs had a second sense about how they (the owners) were feeling was an example of people anthropomorphizing, or at the very least, exaggerating their pets' intelligence and emotional sensitivity.  Until I had lived for a while with Doolin.

After that, a lot of the stories I'd heard began to seem a good bit more plausible.

Just this week, some research supported the contention with hard evidence.  A team of scientists in Belfast studied the responses of four dogs to breath and sweat samples from thirty-six volunteers, before and after doing a stressful exercise -- counting backwards from 9,000 by intervals of 17, without using calculators or pen and paper.  The researchers laid it on thick, telling the participants that it was very important to the study to do the counting exercise quickly and accurately.  A wrong answer got a shouted "No!", followed by being told the most recent correct response and an instruction to pick up from there.  For most of us, this would be a pretty high-stress activity, and would cause stress hormones (like cortisol and epinephrine) to pour into our bloodstreams.

And the breakdown products of those chemicals end up in our breath, sweat, and urine.  What's remarkable is that the four dogs, which had been conditioned to be able to discern between samples containing those breakdown products from ones which did not, correctly distinguished the post-stress breath and sweat samples from the pre-stress ones 93% of the time.

I know that our current dogs are pretty sensitive as well (although nowhere near the level of acuity that Doolin had).  Cleo, our Shiba Inu rescue, is really keyed in to me especially.  I had a couple of seriously high stress things happen in the last couple of months, and whenever I was really in freak-out mode, Cleo followed me around with a very worried expression on her face.  Her curly tail is like a barometer; the tighter the curl, the happier she is.  And when I was struggling, her tail was sagging.  Clearly an unhappy dog.

Cleo the Wonder Floof

So I guess all this stuff isn't our imagination.  Dogs really do sense our emotional states, not by some kind of canine telepathy, but because of plain old biochemistry coupled with an extraordinary sense of smell.

Although I wonder about Doolin.  I still think she was an alien spy, and was relaying information about us back to the Mother Ship.  Maybe the jack toy was some kind of transmitter, I dunno.

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The smell of friendship

A topic I covered in my intro to biology classes was the phenomenon of pheromones.

A pheromone is a chemical secreted by one individual that causes a behavioral change in another member of the same species.  There's a great variety -- sex pheromones (which causes the behavior you see in male dogs when a female dog goes into heat), alarm pheromones (such as the "attack" chemical released by killer bees that causes swarming), territorial pheromones (such as urine marking in wolves), and so on.  They're biochemical signals; much the way hormones signal between organs, pheromones signal between organisms.

This inevitably led to the question, "Do humans have pheromones?"  The answer is, "Probably, but it's hard to demonstrate conclusively."  Certainly, the "pheromonal" perfumes and colognes you've probably seen ads for are ripoffs; there is no evidence that there's anything you could add to a perfume that would act as an aphrodisiac.  (For some reason, I've mostly seen ads for this stuff in science magazines.  Maybe they think we nerds need all the help we can get in the romance department, I dunno.)

One of my AP Biology students years ago got interested in the topic of attractant pheromones, and designed a clever experiment to see if he could detect an effect in humans.  He had a bunch of volunteers agree to the following protocol: (1) shower first thing in the morning; (2) use odorless soap, shampoo, and deodorant, and don't put on any scented products; (3) don't eat any food that could change your body odor, such as garlic, curry, or asparagus; and (4) wear a plain white t-shirt (provided by the researcher) for an entire day, then seal it in a ziplock bag at the end of the day.  He then took the collected t-shirts (I think there were about twenty in all) and got a bunch of students to smell them, and rank them best-to-worst for odor.

[Image licensed under the Creative Commons Lateiner, T-shirt-2, CC BY-SA 3.0]

The results were pretty interesting.  There was a tendency for people to rank higher t-shirts that had been worn by volunteers of their preferred gender.  (There weren't any bisexuals in the test sample; maybe we think everyone smells good, I dunno.)  The most interesting part was that between the t-shirt wearing group and the t-shirt smelling group, there were a couple of pairs of siblings -- and they ranked their siblings as smelling terrible!

Curious results, which I was immediately reminded of when I stumbled on some research out of the Weizmann Institute of Science in Israel which showed there might be a pheromonal aspect not only of sexual attraction, but of friendship.

The procedure they followed was remarkably similar to my student's, if considerably more rigorous and technical.  They recruited twenty pairs of people who reported that they were friends, and further, had "clicked immediately" -- a phenomenon I think we can all relate to.  (It's equally common to meet someone you dislike immediately -- but that'd have been a lot harder to study.)  They then did a similar t-shirt wearing protocol, but at the end of the day, instead of having someone smell it, they used an electronic volatile chemical analyzer to determine what odor-carrying substances there might be in the shirts.

What they found was that the chemistry of the sweat left behind in the t-shirts was remarkably similar between people who were friends.  Further -- and even wilder -- they then had the volunteers pair up with same-sex strangers from the research group, eventually testing all possible same-sex pairings, and had them stand in close proximity for two minutes (in silence).  They then were asked to rank the person from 1 to 100 in terms of how comfortable they were, whether they felt a connection, and whether they'd be interested in meeting the person again.

Across the board, the more similar the pair's sweat chemistry, the higher the rankings were.  "The finding that it could predict clicking by body odor similarity alone—this was really cool," said study co-author Inval Ravreby.  "We were really excited to find this."

The researchers did admit that the effect was small (although statistically significant) and there was a lot of overlap in the data, but the fact that there's a trend at all is pretty amazing.  Human behavior is complex and multifaceted, and it's amazing how much of it is due to subliminal cues.  Despite our generally high opinions of our species, we're still animals -- and we interact with each other not only in human-specific ways but in the more instinctual ways other animals use.

Now, I'm not suggesting that you should try to find friends by walking up and sniffing people.  But maybe that feeling of an instant connection we sometimes have is more due to our sense of smell than it is any kind of cognitive assessment.

Think of that the next time you're having lunch with your best friend.

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The smell of time passing

We once owned a very peculiar border collie named Doolin.  Although from what I've heard, saying "very peculiar" in the same breath as "border collie" is kind of redundant.  The breed has a reputation for being extremely intelligent, hyperactive, job-oriented, and more than a little neurotic, and Doolin fit the bill in all respects.

As far as the "intelligent" part, she's the dog who learned to open the slide bolts on our fence by watching us do it only two or three times.  I wouldn't have believed it unless I'd seen it with my own eyes.  She also took her job very seriously, and by "job" I mean "life."  She had a passion for catching frisbees, but I always got the impression that it wasn't because it was fun.  It was because the Russian judge had only given her a 9.4 on the previous catch and she was determined to improve her score.

There were ways in which her intelligence was almost eerie at times.  I was away from home one time and called Carol to say hi, and apparently Doolin looked at her with question marks in her eyes.  Carol said, "Doolin, it's Daddy!"  Doolin responded by becoming extremely excited and running around the house looking in all of the likely spots -- my office, the recliner, the workshop -- as well as some somewhat less likely places like under the bed.  When the search was unsuccessful, apparently she seemed extremely worried for the rest of the evening.

Not that this was all that different from her usual expression.

One thing that always puzzled us, though, was her ability to sense when we were about to get home.  Doolin would routinely go to the door and stand there on guard before Carol's car pulled into the driveway.  She did the same thing, I heard, when I was about to arrive.  In each case, there was no obvious cue that she could have relied on; we live on a fairly well-traveled stretch of rural highway and even if she heard our cars in the distance, I can't imagine they sound that different from any of the other hundreds of cars that pass by daily.  And my arrival time, especially, varied considerably from day to day, because of after-school commitments.  How, then, did she figure out we were about to get home -- or was it just dart-thrower's bias again, and we were noticing the times she got it right and ignoring all the times she didn't?

According to Alexandra Horowitz, a professor of psychology at Barnard University, there's actually something to this observation.  There are hundreds of anecdotal accounts of the same kind of behavior, enough that (although there hasn't been much in the way of a systematic study) there's almost certainly a reason behind it other than chance.  Horowitz considered the well-documented ability of dogs to follow a scent trail the right direction by sensing where the signal was weakest -- presumably the oldest part of the trail -- and heading toward where it was stronger.  The difference in intensity is minuscule, especially given that to go the right direction the dog can't directly compare the scent right here to the scent a half a kilometer away, but has to compare the scent here to the scent a couple of meters away.

What Horowitz wondered is if dogs are using scent intensity as a kind of clock -- the diminishment of a person's scent signal after they leave the house gives the dog a way of knowing how much time has elapsed.  This makes more sense than any other explanation I've heard, which include (no lie) that dogs are psychic and are telepathically sensing your approach.  Biological clocks of all kinds are only now being investigated and understood, including how they are entrained -- how the internal state is aligned to external cues.  (The most obvious examples of entrainment are the alignment of our sleep cycle to light/dark fluctuations, and seasonal behaviors in other animals like hibernation and migration in response to cues like decreasing day length.)

So it's possible that dogs are entraining this bit of their behavior using their phenomenally sensitive noses.  It'll be interesting to see what Horowitz does with her hypothesis; it's certainly worth testing.  Now, I need to wrap this up because Guinness's biological clock just went off and told him it was time to play ball.  Of course, that happens about fifty times a day, so there may not be anything particularly surprising there.

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This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

[Note: if you purchase this book from the image/link below, part of the proceeds goes to support Skeptophilia!]

The smell of death

In Agatha Christie's wonderful novel The Pale Horse, a group of self-styled witches claim to be able to curse someone to death.  And they're happy to do it for you -- under a dubiously moral but entirely legal scheme wherein you bet the ringleader that your worst enemy is going to die within six weeks.  If your enemy dies, as promised, you pay up.  If not, the witches pay you.

Because, after all, you haven't asked anyone to act as a hit man -- all you've done is speculate that someone is going to die.

Of course, given that it's Christie, there's no chance that there's actually anything supernatural going on, and the death-by-curse scheme is actually a cover for very deliberate murder.  I won't spoil it further for you, because it's a hell of a read (you can buy it at the link above); but the point is that even when things look their woo-iest, there's usually some sort of completely rational explanation behind it.

This all comes up because of a claim I ran across over at the site Mysterious Universe, in an article by Paul Seaburn called, "Psychic Claims She Can Smell Your Impending Doom."  In it, we hear about a woman named Ari Kala, of Hunter Valley, New South Wales, Australia, who claims that she can tell if someone's going to die -- by their smell.

Kala tells about her first experience with this alleged ability, at age twelve, when she detected an odd odor from someone who was dying.  'The night before his death I picked up this odd, sickly sweet rotten kind of smell in the house," Kala said.  "I thought it was the smell of his remains as I had never smelled that before.  But no one else could smell it."

[Image is in the Public Domain]

When she became an adult, she became aware of other psychic abilities (she claims), and started working as a "psychic coach."  But the ability to smell death remained with her.  It wasn't pleasant, she says, and not just because death doesn't smell so good:

Sometimes it feels like a burden.  I used to want to say something, however, I realized it’s not my duty.  It’s kind of useless – how could it help anyone?  How I can walk up to strangers with this smell and help them?  What if they don’t know they are going to die soon?  If I told them that and they weren’t aware, it could be catastrophic.  I don’t see how it’s up to me to interfere with their fate.

Which I suppose makes sense, not to mention the fact that it would make her sound more than a little threatening -- rather like our witches-for-hire in The Pale Horse.

So is there anything to this?  If she'd claimed that she could tell if anyone was going to die, by any means, I'd be inclined to laugh it off.  Such abilities also appear in fiction, most famously in one of the best-ever episodes of The X Files, "Clyde Bruckman's Final Repose."  As interesting as this idea is, there's no way I'll believe someone who claims that they can tell that tomorrow I'm going to get pushed in front of a Mack truck or something because I smell funny.

But what makes me wonder is that Kala says she's only picked up the smell in places where people are dying of natural causes -- hospitals and old-age homes.  It made me think of a study two years ago of dogs that can detect cancer by smell -- in some cases, before the tumor is causing any obvious symptoms.  The ability, which has not been thoroughly researched, is thought to come from dogs' sensitivity to volatile organic compounds released either by the cancer itself or by the body's attempt to fight it, but that piece is speculative.

So could Kala be picking up on something like that?  I suppose it's possible, but the difficulty is that it's not going to be easy to test.  It's not like hospitals would welcome the Death-Sniffing Psychic to wander around in the ICU.

And whatever's going on here -- whether it's a hoax (after all, she's only made the claim after the person in question has died, making it easy enough for her to say she smelled it beforehand), or whether she actually has a nose sensitive to the onset of death -- I'd be willing to bet a significant amount of money that there's a perfectly rational explanation behind it, just as there was with our group of Evil Witches For Hire in The Pale Horse.

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This week's featured book is the amazing Thinking, Fast and Slow by Daniel Kahneman, which looks at the fact that we have two modules in our brain for making decisions -- a fast one, that mostly works intuitively, and a slower one that is logical and rational.  Unfortunately, they frequently disagree on what's the best course of action.  Worse still, trouble ensues when we rely on the intuitive one to the exclusion of the logical one, calling it "common sense" when in fact it's far more likely to come from biases rather than evidence.

Kahneman's book will make you rethink how you come to conclusions -- and make you all too aware of how frail the human reasoning capacity is.

Some call me the pumpkin of love

So it's fall, and the season of pumpkin everything.  Pumpkin pie, pumpkin bread, pumpkin candy, pumpkin pudding, and pumpkin-flavored coffee, for pity's sake.  So I found myself wondering why folks like the stuff so much, to the point where people were basically having multiple orgasms over the latest pumpkin recipe.  So imagine my surprise when I ran across a story in which researchers have found that men consider the smell of pumpkins sexually arousing.

I am not making this up, and if you don't believe me, go here.  Apparently, Dr. Alan Hirsch of the Smell and Taste Research Foundation in Chicago decided to do a study to, and I quote, "investigate the impact of ambient olfactory stimuli upon sexual response in the human male."  And upon much research, they found that the smell that ranked number one in the, um, ready-to-party department was... pumpkin.

[image courtesy of the Wikimedia Commons]

Apparently, the response was especially pronounced when the pumpkin smell was combined with lavender.  And when you added the smell of doughnuts... well, it caused horniness levels that pegged the meters.  All of which made me think, "Were the guys just hungry?"

You may be wondering how they measured all of this stuff.  I know I did, so I did a little research into it.  It turned out that while the guys in the study were breathing air infused with various scents, the researchers were measuring blood flow into their naughty bits.  Blood flow increases during sexual arousal, so there you are.  And lemme tell you, that pumpkin/lavender/doughnut combination really did the trick.

My next question was, who thought of that combination?   It seems like a pretty weird trio to put together.  Did the researchers try various other combinations, and they didn't work so well, and they kept combining random scents until they found one that caused the test subject to get a hard-on?  "Let's see... bologna/caramel/anchovy... nope.   Cinnamon/shrimp/peanut butter... nope. Vinegar/chocolate/bacon... nope."  Until they finally happened to hit on pumpkin/lavender/doughnut, and they found that one was, as it were, hard to beat.

The thing I found the funniest was that although the Triple Threat of pumpkin/lavender/doughnut worked the best, none of the scents turned guys off.  The reason I found this funny is that most guys could have told you that without lots of expensive research.  If a pretty, willing young woman wanted to get seriously amorous in, say, a sewage treatment facility, I suspect that most guys would not be dissuaded by a trivial little thing like an odor so bad that it's actually visible.  Now, the women, on the other hand... in my experience, women are thousands of times more sensitive to odors than guys are.  My wife will come home, and will immediately wrinkle her nose and say, "What in god's name is that smell?" and it will turn out that the cat puked up bits of dead rodent in five separate locations in the living room, and I didn't notice a thing.  Now, I'm willing to entertain the possibility that I am simply oblivious, but I know that other guy friends have corroborated my experience -- women are just more sensitive to smells.  This, I suspect, also explains why guys' locker rooms smell, by and large, like your face is wrapped in a bundle of dirty sweat socks, and nobody seems to mind it all that much.   I can't vouch for what the ladies' locker room smells like, having never been in there, but I don't think I'm going out on a limb in speculating that it's better.

In any case, I can't wait to see what's going to happen when the perfume manufacturers get a hold of this research.  We'll have a whole new line of ladies' scents, with names like "Chanel Eau de Pumpkinne."

So this, I suspect, may explain the rapturous comments that are all over social media about the many ways to consume the signature fall cuisine item.   So however you choose to partake of pumpkin, I hope you enjoy it... and its aftereffects.