Wednesday, January 21, 2009

Instinct Defined?

Heather and I have — or had, anyway, in the early ’90s — a bête noire.

I think that I disliked the man instinctively — or at least had deep reservations — the instant I saw him. It may sound strange coming from me, a round-spectacled dude. But there’s a kind of passive-aggressive (or sometimes just aggressive) asshole who takes on the crunchy-earthy, round-glasses demeanor to hide a level of human empathy that would make the average Wall Street speculator seem grandmotherly.

He was a sales clerk at the main L.L. Bean store in Maine, and as I said I got a weird vibe from him the second Heather and I came into the backpack section. I was looking for a new external-frame pack to take on what was to be a life-transforming, 45-mile through-hike of Isle Royale National Park. He took me to a stand of internal-frame packs, and asked me why I was set on an external.

“Educate me,” he said. I wondered if he realized that I wasn’t dumb enough to miss his patronizing tone.

I don’t remember what I said, but it was probably something along the lines of not wanting to pay more for a pack that wouldn’t tolerate the kind of itinerant-tinker style of packing I was doing at the time. I certainly don’t feel all that strongly about the issue and, both then and now, owned more than one internal frame pack. What turned me off was the feeling that he wanted me, the customer, to justify my choice.

Needless to say, we didn’t buy. But the punch line was that every time thereafter, whenever we visited the main store, we ran into him. Didn’t matter what department; didn’t matter what day of the week, he’d be there. And his looks were nondescript — or maybe context-typical — enough that at first we wouldn’t recognize him. We’d be talking to a clerk, and at some point in an increasingly off-putting conversation we’d realize it was him.

One time, at least, I did recognize him instantly. I saw him, about halfway across the fairly large main floor, standing behind a service counter. Our eyes met, and — I swear to God — he pounded the counter with both fists, like a cave man. It might have been intimidating if it hadn’t been so damned distractingly bizarre.

All of which to make the point that I don’t know why the first encounter with this fellow started off on a weird footing — but a lot of researchers are open to the idea that smells may have something to do with it.

I’m talking about pheromones: airborne chemicals that members of the same species use to communicate with each other. The signal can serve sexual, social, alarm, or even identification purposes. Though the concept is hardly new — people have realized for thousands of years that a bitch in heat will draw males by smell — the word, and the specific definition of what a pheromone is and does, is exactly 50 years old this month, a bit of trivia I learned from an essay in Nature by Oxford pheromone expert Tristram D. Wyatt.

People use the word “instinctive” quite a bit without stopping to think of how meaningless it is. When we say an animal — let alone a human — reacts instinctively to a situation, in fact we’re saying we don’t have the slightest idea how or why she reacted that way, only that, in retrospect, the reaction was appropriate for reasons she couldn’t have thought through.

But what, then, is instinct? How does anybody’s “gut” tell them how to react, often in a split second? Subtle visual cues? ESP? Or are we just judging after the fact, putting a label on lucky guesses and conveniently ignoring the times our guts told us wrong?

The existence of pheromones in species from bacteria to mammals argues that, at least for some situations, the cue may be chemical. And it may be very real.

Now, pheromones are a tricky business in vertebrates, and especially mammals. In insects, where the concept was first defined, it couldn’t be simpler: a male moth encounters a female’s pheromone plume in the air, and he homes in to do the dirty (or try to talk her into it). Signal, response. Easy to conceptualize, easy to measure.

Problem is, mammals don’t do anything for just one reason. So rather than a clear signal/response arc, you get increased interest — subtle, and hard-to-pin-down, changes in behavior as each of the many factors that weigh in on what the animal does next gets its vote. Another level of complication comes from the fact that pheromone signals aren’t single molecules; they’re tightly controlled bouquets of different chemicals, containing strict ratios of each component. That’s one reason the same molecule can be a vital component of the come-hither signal for both Asian elephants and 140 kinds of moth, as Wyatt points out.

The big question, of course, is whether human beings respond to pheromones. We have a number of tantalizing hints that we do:

That last one deserves some elaboration. A lot of people have the common-wisdom version of this story: In 1971, Martha K. McClintock reported that women who lived together tended to synchronize their menstrual periods. In the popluar imagination, this has translated into: when women room together, they have their periods at the same time.

The key word, though, was “tended;” the kind of lock-step synchronization that people often assume doesn’t happen more often than we’d expect by chance. What McClintock actually saw was that, when women lived together, their periods would move toward each other a modest amount that was statistically greater than random chance. She didn’t actually see anything like perfect timing. And subsequent researchers have questioned whether the phenomenon even takes place.

Which is not to say that humans don’t use pheromones to transmit chemical messages that transcend verbal or visual cues. I think that we’re likely to see that idea verified by more data; but the jury’s still out at the moment.

Still, I know there was something I didn’t like about that guy ...


Anonymous said...

I'm pretty sure that the first time I met you, you smelled like scotch.

That, of course, explains why I liked you.

Ken Chiacchia said...

That's 'cause it was the good stuff ...

Sarah said...

I find myself wanting to comment on almost every paragraph of this quite interesting post.

I think I originally read the post just after coming back from a social event that I had gone to alone. I do not tend to like to go to events such as this by myself- even though once you get to know me, you wonder where the off button is, I am horrid at making the first approach. But, I did not want to stay home while everyone else was out celebrating, and the significant other was working, so off I went. Most people there knew each other, I only knew the throwers of the party, so there were many awkward moments, but near to when I had decided to leave, this guy came walking out of a room and we locked eyes about 15 feet from each other. I know I don't *know* this guy, but a jolt went through me, and clearly something similar happened to him. Some sort of (perhapse) primal recognition, even though I am 98% sure I have never seen this person before in my life. I broke eye contact eventually because the staring was becoming pretty obvious. We locked eyes again about 15 minutes later and it happened again- there was unmistakable energy (or something) passing between us. I decided to leave shortly there after, especially due to the aforementioned significant other.

Sounds like that something could have just been a whole bunch of pheremones floating around. I felt better after reading this post, since that would help explain what could have just happened.

Also, having a herd of mammals that come into heat every 18-21 days, there may be a few days a month when no one is in heat, but they certainly don't all come into heat at the same time, or even all in the same week. Most of the females in the herd have been on my farm either since they were born, or were brought in 4-5 years ago.

Heather Houlahan said...

Sarah --

What species is your herd? Cattle? Sheep? Both have about that estrus interval, though sheep of most breeds tend to be seasonal.

Seasonal breeders are typically more influenced by day-length than by their herdmates. But "more influenced" doesn't necessarily mean "only caused by."

Every species' reproductive physiology is unique (that bare fact may be what drives speciation in the first place). Human reproductive physiology is frankly bizarre. But then, so is every species' when you really look at it.

In dogs (non-seasonal breeders descended from probably seasonal breeders), it is butt-obvious that they synchronize estrus. The first bitch in a group to begin estrus almost always "pulls in" other bitches, as much as two months earlier than they would normally cycle. When the influenced bitch is far from her normal estrus schedule, she will often have an abnormal estrus -- a "split heat" or one that is extended. If she is fairly close to her normal time anyway, she will usually have a normal estrus.

But of course, dogs only cycle every six months (on average) not every few weeks.

I expect that the evolutionary explanation is that among herd animals in which one male attaches himself to a group of females and drives off other males (called a "harem" by male biologists), it would be maladaptive for all the females to become receptive and fertile at once. This social pattern would also account for the short cycling in that species. It's also maladaptive to be calving too far apart in time, since the herd in nature has to adjust its movements to accommodate newborns. And there's an advantage to "flooding" with newborns, in that predators simply cannot eat them all if they all arrive at once.

Sarah said...


I have Nigerian Dwarf goats which are year-round breeders. Being Equatorial in origin means that there is little advantage to having kids at one time of year versus another. I can clearly see that it makes sense to have lots of kids arrive at once because the predators can really only eat so many. It has appeared to us that part of the reason for baby buck kids is to act as easy prey to allow their sisters to get away. My husband has been heard saying to a young baby goat "Geeze, you're so dumb you must be a buck".

Having attended a women's college for two years, I was interested to see if we would (as my mom had speculated) all start cycling on the same schedule by the end of the school year. There were nine of us in my suite all living pretty closely together, and I don't think anyone noticed any changes in when they cycled- and yes, this was the land of TMI, so we would have noted something along those lines.

I hadn't realized that bitches could have that much of a pull on each other- that's pretty impressive.

Ken Chiacchia said...

I stand corrected: My comments on synchronization really only applied to bizarre (Heather picked the right word) human reproduction and may not hold for pack or herd animals that cycle regularly through the year and may in fact need to reproduce at the same time.

Anonymous said...

I seem to be in heat every eight (8) hours, on average, I believe. However, that's only a subjective impression.