Reconnect With Nature Blog

A Conversation On Anecdotal Evidence

This is an email conversation between Randall Johnson and Con Slobodchikoff on the value of anecdotal evidence in biology.

Randall Johnson:
I've submitted a new Dog Behavior Blog comment (http://www/dogbehaviorblog.com) in response to your latest entry, "A Dog's Concern for a Cat". Focus: anecdotal evidence as a useful source of information.

Comment on Dog Behavior Blog: This incident joins a long list of other reported observations that clearly show that dogs are capable of feelings we associate with empathy and sympathy and that they extend these feelings toward other species.  If we had only a handful of stories like this one, then we could say this is anecdotal evidence, but when there are hundreds of stories reporting similar behavior, we no longer have anecdotal evidence, but rather a solid body of observational evidence. Since the human environment is the dog’s natural habitat, then these reports can also be considered as field observations, which is a respected source of data-gathering. I don’t know if anyone has decided how many anecdotes it takes to cross over to the realm of observational field data, but if this hasn’t been done yet, it’s high time some kind of marker was devised. And, in defense of anecdotal evidence, Hungarian ethologist Vilmos Csányi of the Eötvös Loránd University, who has devoted more than a decade to investigating dogs’ cognitive abilities, has used anecdotes on many occasions to inspire more formal experimental investigations.

Con Slobodchikoff:
Thank you for your insightful comment, which I published on the dog behavior blog.  As you know, "anecdotal evidence" can sometimes be used as a convenient way to sweep inconvenient evidence under the proverbial rug. There surely has to be some kind of standard for how much anecdotal evidence constitutes proof, but I don't know of any standards. However, if you go back to the papers in biology journals of 60-70 years ago, much of what was presented there was in the form of anecdotal evidence. Where would science be today if we discounted such evidence?

Randall Johnson:
While writing my comment, I was pretty sure there was no standard for anecdotal evidence. You raised a good point about this kind of evidence having played an honorable role in science in the past.
Somewhere along the way, it was stripped of some of its original credibility and we need to get it back or devise some clear guidelines for its use as a source of evidence.

I am submitting a brief comment in response to the "Are We Unique?" essay on the Reconnect With Nature blog. (I'm surprised this one hasn't generated more responses.)

Con Slobodchikoff:
First, thanks for your comment on Are We Unique. As usual, a great comment! I have posted it, and I hope that it raises some discussion or at least some thoughts on the part of the readers.

For the anecdotal evidence part, it seems to me that biologists have bought into the idea that experimentation is the only way to obtain valid biological data. This is fine for lab studies, but experiments are often difficult to do in nature, under field conditions, and a lot of the time we are left with observations that cannot be quantified or even repeated. In my mind, this does not make them any the less valid. I think we need to come back to a point where a certain quantity of similar observations is accepted as proof of the validity of a particular behavior or biological circumstance.

Randall Johnson:
My question, at the beginning of this discussion, was: At what point does an observed behavior stop being treated as anecdotal evidence and be recognized as observational data? Most definitions I’ve looked at stated that anecdotal evidence is limited to one or a small number of cases, but no one, so far, has said, “Well, if you have 10 cases of “X” behavior, it’s anecdotal, but if you have 11 cases, it’s observational data.” Maybe it’s not all that important, but considering science strives for precision, there’s a big fuzzy area here that’s calling out for better definition.

However, the larger issue is still related to the credibility of anecdotal evidence. In the late 19th century, it fell under some heavy criticism, largely because George Romanes, Charles Darwin’s protégé and an eminent biologist in his own right, relied heavily on anecdotal methodology to develop his theory of comparative psychology and, to this day, there still seems to be a lingering ‘cloud of doubt’ hanging over it.

Then, the other day, I came across a news item from 2005 on the Science Week web site that I found particularly insightful. In discussing numbers and counting in chimpanzees, the writer pointed out that one problem with investigating non-human primates is that experiments can’t be done on large populations because such populations either don’t exist or are prohibitively expensive to maintain. The result is that reported experiments are often "anecdotal", i.e., experiments involving only a few or even a single animal subject. The writer then stated: “But anecdotal evidence can often be of great significance and have startling implications: a report, even in a single animal, of important abstract abilities, numeric or conceptual, is worthy of attention, if only because it may destroy old myths and point to new directions in methodology.”

The debate continues. Although I’m not a gambling man myself, I’m willing to bet that, in the end, anecdotal evidence will regain its former luster and that the academic / scientific community will universally recognize it as a valid—and valuable—source of data. Let’s face it. There are still lots of old myths out waiting to be slain.

Con Slobodchikoff:
Yes, it is true that many experiments cannot be done on multiple animals because of the cost or the lack of animals. I was talking just the other day to someone about Alex, the parrot (see earlier post: A Tribute To Washoe And Alex), and the person I was talking to pointed out that we can’t generalize from only one parrot to say that parrots might have language-like abilities or the cognitive skills to count and identify colors and shapes: Alex might have been a genius among parrots, a feathered Einstein. That might very well be true, and Irene Pepperberg is doing careful experiments with other parrots to test for this possibility. However, Pepperberg’s extensive experiments with Alex show that not all parrots are incapable of complex cognitive skills.

Unlike Pepperberg’s work with Alex, many observations cannot be repeated on command. Does that invalidate them? I guess it depends on the credibility of the observer and the relative novelty of the observation.  If I say that I saw my dog burying a bone in my back yard, no one would question this anecdotal observation. However, if I say that I saw my dog surfing the internet on my computer, lots of people would probably discount that as pure fantasy, because it does not fit the current dogma of what dogs are capable of doing and no one else has reported this (and no, my dog does not surf the internet).

But we have to be careful about discarding observations that do not fit our preconceived notions. If an observation comes from a credible source and can be documented, then that observation can have the seeds of changing our thinking about the world around us.

As William James once said, you need only one white crow to disprove the assertion that all crows are black.

A Wasp Tale

At the beginning of summer, my wife opened up our outdoor grill, only to find that paper wasps (Polistes arizonensis) had built a nest hanging from the upper grill shelf. The nest formed a disk that was about 5 cm (about 2 inches) in diameter. She quickly closed the grill cover and came to ask me to do something about the wasps.

We did not want to kill them, so I thought that if I left the grill cover open, the heat of our summer days would drive the wasps to abandon the nest.  I opened the grill cover in the early morning, when the temperature was still cool and the wasps were not active. Since the temperature really soars during the heat of the day, I thought it would take the wasps only a few days to leave their nest.

Every day I watched them through our kitchen window to see what they would do. Rather than abandoning the nest, the wasps took their exposure to the sun in stride. During the heat of the day, they would all cluster on the underside of the nest, in the shade. As the sun started going down and the temperature started cooling off, they would crawl up to the topside of the nest and absorb some heat for the coming cooler night.

For the next month, I watched the wasps building up and maintaining their nest. The diameter of the nest is now about 13 cm (about 7 inches), and the wasps show no inclination to slow down their activity.

But now the Arizona monsoon is gathering. This is a time of violent rainstorms and thunderstorms. Each morning during the monsoon the day dawns clear and sunny, but by noon the clouds gather and the rain starts, lasting in fitful bursts of moisture through the early evening hours, and sometimes throughout the night.

I know that the rains are coming, and when they arrive, the paper construction of the wasp nest will be destroyed. Yet the wasps continue unfazed by the coming prospect of losing their nest.

I can say that the wasps are operating on sheer instinct and have no prior knowledge of the coming debacle that will engulf their home.   But then I think of how we humans do exactly the same thing, even though we supposedly are aware of the consequences. I remember watching villagers build houses of out lava on the slopes of a still-rumbling and smoking volcano in Guatemala. And I lived in San Francisco, where everyone knows that a big earthquake is going to arrive someday, but everyone hopes that it won’t be during their time.

We humans live in perilous places and we hope for the best. Perhaps the wasps are also hoping for the best. (I’m sure that some dogmatic scientists will say that wasps are not capable of hope, to which my reply is, how exactly do you know this, other than through your unverified opinion?).

But it does show that we humans and the wasps have something in common: We all are reluctant to leave behind the place that we call home.