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:

• our olfactory epithelia contain receptors similar to those that detect pheromones in other species
• our armpits (with some help from bacteria) produce molecules similar to animal pheromones
• we tend to marry people whose pheromone-associated genes complement our own
• all those musky colognes and perfumes, which employ animal pheromones to get oomph
• the college roommate thing
  

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 ...