The recent US election brought home once again the reluctance of large swathes of educated population to accept the ‘theory’ of evolution. A mere passing mention of the ceaseless creationist vs evolutionist debate triggers a stereotypical reaction from anyone who considers oneself even remotely related to scientific circles (graduate students, for example): a sigh, an awkward little laugh and apparent willingness to change subject, or – if you are lucky – a feat of righteous wrath and an impromptu lecture on the dire necessity of ‘educating the masses’.
Apparently 4 in 10 Americans Believe God Created Earth 10,000 Years Ago. NBC news.
Nevertheless, if we take a long and honest look at the scientific community itself, it is hard to sustain an impression of impeccably reasoned unified position on the topic. To start with, even though Dobzhanky’s quote has been worn and torn, getting tacked onto every undergraduate biology powerpoint, and even occasionally making it onto life science researchers’ slides when they preach to a crowd of gadget-armed AI folks, I would hesitate to claim that many working biologists have a good grasp beyond the modern synthesis and fewer still have kept up with molecular genetics and its implications. Now, important issues as these are, they seem relegated to cottage industries prefaced by the cautionary note ‘Evolutionary’ or ‘Comparative’ – Evolutionary Biology, Comparative Anatomy. And then within these academic oases, the dons are left to argue about homologues and analogues, pallia and subpallia.
In Europe the situation is slightly better, but do our practices conform to our alleged beliefs? New Scientist. 198 (2652): 31
It seems to me that the term itself – ‘Evolutionary Biology’ – is a pleonasm. All biology is ‘evolutionary’. If we follow Darwin and Dobzhansky. But we do not. Or at least, we want to keep one foot at the top of the scala naturae. At this point, you may be justifiably wondering what launched me into this rant. Let’s take a look at three telling examples.
Guidelines for ethical animal experimentation
All good intentions seem to start with three Rs. Only if in the case of environmentalism it is ‘reduce, reuse, recycle’, in the context of animal experiments they refer to ‘replace, reduce, refine’. This trinity was first enshrined in the 1959 book ‘The Principles of Humane Experimental Technique’ by Russell and Burch, which has become a veritable Bible of experimental ethics. Of particular interest to us, is the first ‘R’ on the list. Replace, Russel & Bruch, urge the researches, higher animals with the lower ones. Or, better yet, satisfy your curiosity with tissue culture and computer simulations.
Despite the seemingly unanimous acceptance of evolution among biologists, our ethical guidelines lag far behind. Just as in this 1579 drawing of the great chain of being from Didacus Valades Rhetorica Christiana, we talk about ‘higher’ and ‘lower’ animals.
At first sight, it seems plausible: surely, fish cannot feel pain, but the cuddly warm little mice will. So let’s try and shove all our experiments ‘down to the root’ of the ‘evolutionary tree’. Except, of course, there is no vertical hierarchy. And as much as we like to assuage our conscience, there simply doesn’t appear to be a good argument for why if we care about the feelings of mammals, the same does not apply to fish and invertebrates. There’s a never-ending game of double-standards: bees are paraded as paragons of intelligence, prime communicators; crows are poster children for ingenuity, figuring out complex task sequences to get what they want. That’s on the one hand. On the other, however, the knee jerk reaction – if you have to choose whether to decapitate one mouse or to eradicate a hive swarming with bees, you are, in fact, ethically obliged to choose the latter.
Intuitively obvious misconceptions about ‘the human advantage’
Dr. Suzana Herculano-Houzel stormed into the field of neuroanatomy and debunked quite a few unanimously accepted orthodoxies appeared to be written in stone. She was first to question the beautiful ubiquitously cited number of 100 billion neurons in the human brain (it’s 86 billion, in fact). She drew attention to the fact (for this, one didn’t even have to grind brains and count neurons, just go look at a modern species ‘dendrogram’, tracing the evolutionary development of major clades from a common ancestor) that the sheer idea of the ‘reptilian brain’ in humans is downright incoherent. It is impossible to inherit a large chunk of the brain from the clade that is at best our ‘evolutionary cousin’, but not a direct predecessor. She showed that the human brain is not ‘too big for our body’. Within the primate species, the scaling law is different from other mammals. In this context, the human brain is just as big as would be expected for the primate of our size.
In her book, Dr. Herculano-Houzel gives a summary of her illuminating research in comparative neuroanatomy and recounts just how many ‘hoops’ she had to jump through to get the acceptance of the scientific community
It is hard not to be astounded by how all these ideas have gone unquestioned for years because of a dubious merit of ‘intuitive plausibility’. Humans like to think of themselves as being ‘higher, faster, stronger’. And even if they accept evolution, they want to be the crowning jewel of it with the most neurons, biggest brains and the nakedness of reptilian appendages having been long covered with the exalting power of the neocortex. Dr. Herculano- Houzel met enormous resistance (and even scorn) in response to her reports. Underneath all this, by now a familiar adage is lurking: if we ‘buy’ into evolution, it has to be goal-directed and progressive, paving out for us a highway to heaven.
Painful facial expressions and prefrontal cortex in the mouse
Last but not least, my favorite example of the Dr. Jekyll & Mr. Hyde co-existing in the scientific community in broad daylight.
It’s been reported (and apparently taken seriously enough to be included in the official training handbook for obtaining an animal experimenter license in Germany) that mice not only are capable of perceiving pain, but also are skilled at communicating it to their cage mates through an array of distinct facial expressions.
When it is fitting to our purposes, we are willing to ‘look into the rodent soul’ and concede a mouse is not much of a ‘lower’ animal than a human.
Across the hallway, however, there’s an ongoing controversy about the existence (or lack thereof) of the prefrontal cortex in the mouse. On the one hand, cytoarchitectonic and genetic markers do not support this claim. On the other hand, if one applies for grants to model higher cognitive functions in mice (and eventually cure schizophrenia, AD, Parkinson’s and figure out decision-making on the way), then one is forced to push the poor mouse cortex into the Procrustean bed of the human brain theory. Thus for decades goes the back and forth of this make-believe, generations change, new enthusiasts search with ever bigger torchlights, and the lab expenditure sheet is the only thing staring back at them.
There are different ways to cobble together a brain that’s good enough for survival (change size of structures, number of neurons, dispense with unnecessary appendages altogether) of a particular species. And it’s OK. We’d do better if we admit it and start studying animal brains in their own right, in terms of their particular ecology and evolutionary history. From Herculano-Houzel (2012) PNAS.
Apparently, when it’s good for us to grant mice the ability to express pain (and, seamlessly, giving ourselves the capacity to unambiguously decipher it) so that we can don our saintly robes and deign to relieving their suffering, mice have enough cognitive ‘juice’ and we are happy to proclaim allegiance to the idea that ‘all species are made equal’. The baton is then immediately picked up by the supporters of the mouse PFC. But this highly selective acceptance of evolution is tragically misplaced. It appears that precisely in this case a clear-eyed, long and hard look would be needed to put the debate on solid evolutionary grounds. This is a crucial issue with acute practical consequences: more drugs go into clinical trials each month, some of which will never be ‘translational’ for the reasons that any non-partisan high school biology student can name.
This illuminating talk on the contradictions in arguments about animal models was given at the NIH (whose videocasts are an all-round wonderful source of reviews on many neuroscience fields by the most active and forward-looking PIs).
All this is not to say that we should try to avail ourselves of the ethical guidelines, or that human brains are just like your next chimp’s, or stop animal experiments. It is just to emphasize once again the brute fact of the sociology of science. Science is done by people, and we are prone to biases. If we do not correct each other, or worse still, institutionalize faulty beliefs and bash dissenters, this activity that we are engaging in becomes a self-congratulatory collective exercise in confirmation bias.
This has not been meant as a philosophical treatise, the arguments are not razor sharp. My aim was to canvass the situation as it appears to me and, hopefully, give you some food for thought too.