People are irrational


One of my funnier stories comes from a conversation at a social gathering. I think it was a party involving parents of preschool-aged kids, but the details are fuzzy because I only really remember the funny part.

I was standing around with group when a guy asked us all the “So, what do you do?” question. I don’t remember if I said I was a biologist or a professor or an ecologist or whatnot. But the interrogation didn’t last long before he found out that I work with ants, in a Costa Rican rainforest. (Where I happen to be at this writing, by the way.)

After learning I work in a rainforest, this amiable guy spent a few minutes teaching the little group of us parents about the amazing ants of the rainforest. You know, he just met a bona fide expert on rainforest ants, so he thought it would be a good idea to share his own expertise. He was down here on vacation and had a guide show him all kinds of animals. He explained how leafcutter ants gather leaves, how sloths like a particular species of tree, and so on.

I’m okay with receiving a vague lesson in tropical natural history in this context. Frankly, this guy was more enthusiastic than I could ever get about leafcutter ants. If we are trying to get people interested in nature, the last thing that this conversation needs is The Expert correcting what might be considered to be nitpicking details. I prefer not to discuss the nuts-and-bolts of my research unless someone is particularly interested in asking about it. This guy was so excited about his trip to the rainforest, I didn’t intercede.

Well, I didn’t intercede until I did. I really couldn’t stop myself with this one:

He was saying that there was an ant in Costa Rica that was so poisonous that it could kill you with just one bite*. He said the guide pointed the ant out to him. He saw this deadly ant with his own eyes.

I’m down with enthusiastic-but-bumbling natural history, but I didn’t want to really be a bystander to promoting an irrational fear of insects, especially my organism of choice. Also, I was really curious how he learned this non-fact!? What kind of miscommunication happened that would lead to this kind of understanding? I didn’t want to embarrass the guy, nor did I want to be the know-it-all academic, but this was something I wanted to figure out.

I said, really? As far as I knew there were no deadly ants in Costa Rica, just some ones that rarely cause allergic reactions in Australia. He said no, he was sure. I asked if he remembered the name of the ant, or what it looked like. He couldn’t really fish it out, but the guide was so certain about it, and the guide was definitely an expert. (And that was probably true, many of the guides down here are truly expert.)

I took a different tack against this problem. I thought, what critters in the forest are capable of killing you with a single bite/sting? Hmm. Well, no invertebrates I can think of, though some have very painful stings. In theory a jaguar might be able to bite your head off, perhaps a puma. Then there are snakes: corals, and the vipers —  bushmaster, the eyelash viper, hog nose viper, and of course the fer-de-lance.


So I asked him, “Is it possible that these deadly animals were called Fairdell Ants?”

His eyes lit up, eyebrows animated: “Yes! That’s it! Fairdell ants! One bite from a Fairdell Ant will kill you. There’s no treatment for it.”

“Um, I’m not sure how to break this to you, but the Fer-De-Lance is not an ant, it’s a snake.”

“No, it’s not! It’s an ant.”

“Um, okay… Fer-de-lance is taken from French, meaning ‘tip of the spear.’ I’m betting you misheard the guide, who might not have expressed himself well. [I’ll throw the guide under the bus on this one it it helps the guy save face.] The fer-de-lance in Spanish is ‘terciopelo’ which means ‘velvet.’ For what it’s worth, the scientific name is Bothrops asper. But most North Americans just call them fer-de-lances.

“There might be a snake called that, but I’m telling you, it might have a different name, but there is this ant down there that can kill you.”

“Do you know what it looks like?”

“Well, it’s really really big, and it’s black.”

“That sounds like the bullet ant. It does have a really really painful sting, supposedly the most painful sting in the world. But as far as I know — and I do believe I would know — nobody has been killed by a single bullet ant sting.”

“How do you know that?”

“Well, I work on them. I’ve been stung, once. I go through risk management paperwork for students to do research down there. If anybody has been killed by any kind of ant bite or sting in Costa Rica, I’d know about it.”

“Well, I suppose bullet ants don’t kill, but the fairdell ants I saw do.”

I wish he was joking. I didn’t actually want to argue with this guy, I was just trying to let him and others know that ants don’t kill, and I solved the little mystery. So I let it go, and he went home thinking that Costa Rica has deadly Fairdell Ants. I honestly have no idea what the other people observing this conversation thought.

This conversation was about a venomous animal. But it may well have been about climate change, or evolution, or the big bang, or the relationship between genetic engineering and food safety. Or inquiry-based instruction. Or pay equity. Or any other topic in which evidence and rationality don’t seem to affect the outcome of discourse.

As a scientist, I like to think that I make decisions that make sense and are reasonable. I accomplish that at least sometimes.

I have expected the same from others. When I’m discussing something with someone — or trying to understand how or why people do things — I’ve started with the presumption that people make decisions that are logical, or based on actual facts. People might not be using high quality or true facts, but they’d be using information to make their decisions.

In recent months, I’ve decided to change my mind. I am no longer entering personal interactions with the assumption that people are using reason or assessing facts to make decisions. I am now entering interactions with a new expectation: People make decisions based on preexisting bias and emotion. People rarely use facts to assess a situation. For big things and small things, for complex things and simple things. Bias and emotion. Not facts, not logic.

I’m open to the notion that people will make rational decisions, but I’m no longer making that assumption. (I recognize that people in marketing and trial lawyers must be thinking to themselves, duh, of course.)

This has worked out remarkably well for me, because now the world makes a helluva lot more sense than it used to.

Now I get why the Fairdell Ant guy didn’t believe me. He had an emotional experience visiting the rainforest and getting a tour from a guide. He was thrilled about it. And he wasn’t going to let facts from an expert get in the way of his experience that was more important to him.

A lot of other things make sense now too. Why is it that so many students won’t do easy assignments worth 20% of their grade but will go through hell to get extra credit worth 0.5% of their grade? Why is it that so many professors insist that inquiry-based lessons are not as good as lecturing when the data are so clearly in contradiction? Why is it that an administrator is so opposed to policy X but pushes for policy Y even though data clearly show that policy Y is more effective? Why did plate tectonics take so long to catch on? Why do people keep insisting that competition structures ant communities even though there is almost no evidence to support that claim? Why do taxpayers continually take money away from education even though every dollar invested in education results in massive financial gain in the long run?

It’s just this simple: People are irrational.

Going through life with an expectation that people should be acting rationally is a recipe for disappointment.

As a corollary, if you are attempting to elicit certain kinds of responses from people, then you need to appeal to their biases and emotions at least as much as their rationality. This goes a long way towards having healthy interactions with students. And colleagues. And reviewers. And everybody else in your professional and private life.

Perhaps embracing this fact can help us understand ourselves a little better too. Don’t decide whether that is true based on your emotions! If so many other people make most of their decisions principally using bias and emotion, why should we be any different? Well, we’re special, because we’re scientists? Maybe just a little bit. Or maybe not.




*That is quite false. Putting aside the distinction between poison and venom, there is actually one kind of ant that is capable of killing some people with a single sting, those in the Myrmecia pilosula complex, Australian and introduced into New Zealand. When people die, it is from an allergic reaction, just like a small fraction of people go into anaphylactic shock when stung by a single honeybee. Considering how variable ant venoms are, it’s interesting that no other species is known to cause deadly allergic reactions.

14 thoughts on “People are irrational

  1. This blog struck a cord with me. Especially the bit “Why do taxpayers continually take money away from education even though every dollar invested in education results in massive financial gain in the long run?”. But I like to think it is the role of scientists to put right some of these things, put the facts in the correct places. Great blog!

  2. Ha — congratulations, you were just mansplained to! I suspect a lot of other female scientists recognize this type of interaction and have many stories about dealing with it during social engagements. Not to minimize what you went through at all — and I think you’ve identified some important broader issues that contributed to it — it just was such a familiar experience that I had to laugh! I love the “Fairdell ants” malapropism. It’s so obvious that you had figured out exactly where the misunderstanding arose that the guy’s continued resistance is just comical.

  3. Great post Terry! The only real thing that may sometimes distinguish scientists is that we can acknowledge what we don’t know. Or catch ourselves when we’re going on about something we really know nothing about (or only a little about). I like to ask questions now, more than pontificate…I operate like Jon Snow “I know nothing”.

    It’s a hard thing to balance; we’re supposed to be experts in one thing, but I find it hard to keep up with my field let alone anything else. So we’re both knowledgeable and not all at the same time; like nearly every scientist can explain evolution or climate change and how certain the science is without being an expert; since we trust our colleagues in other fields have come to a consensus or see how it shows up in our own work sometimes.

    Also, I love the eggcorn here. Fer-de-lance to Fairdell ants. The guy probably heard both and conflated them in his mind some how.

    It’s hard to be a confident individual given what we now know about hte human mind & its cognitive biases…it stops me from moving forward sometimes (as do too many facts…analysis paralysis!). Trying to get over it so maybe I can grow and move forward in life re: career, and other things.

    OK, done pontificating. Thanks for the great post. & hope the field season is going well in CR!

  4. I try to talk about this with students and I joke about what our “monkey brains” are good or bad at doing. So much more of the world makes more sense when we remember how irrational we are. It takes continual practice to work against. We tend to have areas of thought were we are more rational and areas where we are less so.

  5. This was a very cool post Terry! As a plant biologist I’ve had many of these dinner party conversations about genetically modified plants with people who “just know that they are bad and dangerous”, but have no understanding of the science. It used to be incredibly frustrating, but now I just do my best to educate people in a non-condescending way and consider that a win. I agree with lyra211 that this is exactly what mansplaining is like.

  6. Yes! I’ve had a few of these discussions re: GMOs too. And like you, I try to just state the facts & be humorous about it & say what is/isn’t possible w/ GM, but unsure if I’ve actually convinced anyone. I actually run more into the “Monsanto rules the world” narrative most often…which they don’t, but at the same time, they do carry some weight in the biotech world (I know many scientists that work there).

  7. Very relatable. As a Ph.D. toxicologist, I cringe when health nuts talk about “detoxing” or “sweating out toxins” or some other variation. On the rare occasions when I try to correct the pseudoscience (rare because I know that it’s usually wasted effort), the argument to which many people retreat is the old “I heard this (or read it in a book/website) from a REAL doctor.” (Thanks, Dr. Oz.) Then I feel compelled to explain that an MD is a professional degree, not a true doctorate because it is does not require an original contribution to our collective knowledge (not in the US, anyway). At that point, the other person’s eyes usually glaze over and they probably think I’m just a bitter jerk.

  8. Great story! Spot on analysis! I’m sure we can all relate. I research advanced nuclear power — the cleanest and safest baseload power source known to man — and whooo baby, the “well-know” misinformation I’ve tried ( and failed) to correct….

  9. You’ll probably like the books by Dan Ariely on the topic of irrationality – which totally support your point and are a funny read.

  10. I love the term mansplaining! I was the only woman working in the construction industry for many years in my greater neighborhood. I experienced mansplaining on a regular basis. Thanks for the term.

    I once made to mistake of mentioning the butter/margarine choice to a bunch of nutritionist. I was almost guilty of mansplaining, but thankful I was smart enough to stop talking then.

    Great blog, Terry!

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