Archive for the ‘experiments’ Category
Bayesian probability, sans maths (mostly)
Okay time to get back to sciency stuff, to try to get my head around things I should know more about. Bayesian statistics and probability have been brought to the periphery of my attention many times over the years, but my current slow reading of Daniel Kahneman’s Thinking fast and slow has challenged me to master it once and for all (and then doubtless to forget about it forevermore).
I’ve started a couple of pieces on this topic in the past week or so, and abandoned them along with all hope of making sense of what is no doubt a doddle for the cognoscenti, so I clearly need to keep it simple for my own sake. The reason I’m interested is because critics and analysts of both scientific research and political policy-making often complain that Bayesian reasoning is insufficiently utilised, to the detriment of such activities. I can’t pretend that I’ll be able to help out though!
So Thomas Bayes was an 18th century English statistician who left a theorem behind in his unpublished papers, apparently underestimating its significance. The person most responsible for utilising and popularising Bayes’ work was the French polymath Pierre-Simon Laplace. The theorem, or rule, is captured mathematically thusly:
where A and B are events, and P(B), that is, the probability of event B, is not equal to zero. In statistics, the probability of an event’s occurrence ranges from 0 to 1 – meaning zero probability to total certainty.
I do, at least, understand the above equation, which, wordwise, means that the probability of A occurring, given that B has occurred, is equal to the probability of B occurring, given that A has occurred, multiplied by the probability of A’s occurrence, all divided by the probability of B’s occurrence. However, after tackling a few video mini-lectures on the topic I’ve decided to give up and focus on Kahneman’s largely non-mathematical treatment with regard to decision-making. The theorem, or rule, presents, as Kahneman puts it, ‘the logic of how people should change their mind in the light of evidence’. Here’s how Kahneman first describes it:
Bayes’ rule specifies how prior beliefs… should be combined with the diagnosticity of the evidence, the degree to which it favours the hypothesis over the alternative.
D Kahneman, Thinking fast and slow, p154
In the most simple example – if you believe that there’s a 65% chance of rain tomorrow, you really need to believe that there’s a 35% chance of no rain tomorrow, rather than any alternative figure. That seems logical enough, but take this example re US Presidential elections:
… if you believe there’s a 30% chance that candidate x will be elected President, and an 80% chance that he’ll be re-elected if he wins first time, then you must believe that the chances that he will be elected twice in a row are 24%.
This is also logical, but not obvious to a surprisingly large percentage of people. What appears to ‘throw’ people is a story, a causal narrative. They imagine a candidate winning, somewhat against the odds, then proving her worth in office and winning easily next time round – this story deceives them into defying logic and imagining that the chance of her winning twice in a row is greater than that of winning first time around – which is a logical impossibility. Kahneman places this kind of irrationalism within the frame of system 1 v system 2 thinking – roughly equivalent to intuition v concentrated reasoning. His solution to the problem of this kind of suasion-by-story is to step back and take greater stock of the ‘diagnosticity’ of what you already know, or what you have predicted, and how it affects any further related predictions. We’re apparently very bad at this.
There are many examples throughout the book of failure to reason effectively from information about base rates, often described as ‘base-rate neglect’. A base rate is a statistical fact which should be taken into account when considering a further probability. For example, when given information about the character of a a fictional person T, information that was deliberately designed to suggest he was stereotypical of a librarian, research participants gave the person a much higher probability of being a librarian rather than a farmer, even though they knew, or should have known, that the number of persons employed as farmers was higher by a large factor than those employed as librarians (the base rate of librarians in the workforce). Of course the degree to which the base rate was made salient to participants affected their predictions.
Here’s a delicious example of the application, or failure to apply, Bayes’ rule:
A cab was involved in a hit-and-run at night. Two cab companies, Green Cabs and Blue Cabs, operate in the city. You’re given the following data:
– 85% of the cabs in the city are Green, 15% are Blue.
– A witness identified the cab as Blue. The court tested the reliability of the witness under the circumstances that existed on the night of the accident and concluded that the witness correctly identified each one of the two colours 80% of the time and failed 20% of the time.
What is the probability that the car involved in the accident was Blue rather than Green?
D Kahneman, Thinking fast and slow, p166
It’s an artificial scenario, granted, but if we accept the accuracy of those probabilities, we can say this: given that the base rate of Blue cars is 15%, and the probability of the witness identifying the car accurately is 80%, we have this figure for the dividend – (.15/.85) x (.8/.2) =.706. Dividing this by the range of probabilities plus the dividend (1.706) gives approximately 41%.
So how close were the research participants to this figure? Most participants ignored the statistical data – the base rates – and gave the figure of 80%. They were more convinced by the witness. However, when the problem was framed differently, by providing causal rather than statistical data, participants’ guesses were more accurate. Here’s the alternative presentation of the scenario:
You’re given the following data:
– the two companies operate the same number of cabs, but Green cabs are involved in 85% of accidents
– the information about the witness is the same as previously presented
The mathematical result is the same, but this time the guesses were much closer to the correct figure. The difference lay in the framing. Green cabs cause accidents. That was the fact that jumped out, whereas in the first scenario, the fact that most clearly jumped out was that the witness identified the offending car as Blue. The statistical data in scenario 1 was largely ignored. In the second scenario, the witness’s identification of the Blue car moderated the tendency to blame the Green cars, whereas in scenario 1 there was no ‘story’ about Green cars causing accidents and the blame shifted almost entirely to the Blue cars, based on the witness’s story. Kahneman named his chapter about this tendency ‘Causes trump statistics’.
So there are causal and statistical base rates, and the lesson is that in much of our intuitive understanding of probability, we simply pay far more attention to causal base rates, largely to our detriment. Also, our causal inferences tend to be stereotyped, so that only if we are faced with surprising causal rates, in particular cases and not presented statistically, are we liable to adjust our probabilistic assessments. Kahneman presents some striking illustrations of this in the research literature. Causal information creates bias in other areas of behaviour assessment too, of course, as in the phenomenon of regression to the mean, but that’s for another day, perhaps.
On Massimo Pigliucci on scientism: part 1 – what is science?
I’ve written a couple of posts on scientism (all references below), which is for some reason a topic that always gets me exercised. So a recent brief interview with the philosopher Massimo Pigliucci, on the Point of Inquiry podcast, has set me back on the wagon. This blog post will be a piece by piece analysis of (some bits of) the interview.
I’ll begin with the Point of Inquiry host Kavin Senapathy’s intro, in which she gives a definition of scientism as:
this idea that the scientific method is the only worthwhile way of answering questions, and that any question that can’t be tackled using science is therefore unimportant or frivolous, and this often seems to apply to areas of social or political concern. In practice, those with a scientific approach try to colonise other areas of expertise and call them science. So this is really an ideology
So scientism is an ideology (and Pigliucci agrees with this later in the interview). I must say I’m skeptical of both terms, but let me focus for now on ‘ideology’. I once recall, during a meeting of secular and religious humanists, an old bloke beside me describing atheism as an ideology. The term’s often abused, and almost invariably used as a put-down. Only the other day, our former PM, John Howard, not known for his scientific literacy, complained that the recent federal election was marred by ‘climate change ideology’, by which he clearly meant the view that anthropogenic global warming is an issue.
More important here, though, is the attempt to define scientism, which makes me wonder if scientism is really a thing at all. The problem for me here is that it’s obvious that any area of ‘social or political concern’ will benefit from rigorous thought, or inference, based on various forms of evidence. Whether you want to call it science or not isn’t, for me, a major issue. For example, a state’s immigration policy would best be based on a range of concerns and analyses about its population, its resources, its productivity, its degree of integration, its previous experience of immigration, its relations with neighbours, the needs and aspirations of the immigrants, and so on. These factors can’t simply be intuited (though politicians generally do base their decisions on intuition, or ideology), but whether such analysis rises to the level of science doubtless depends on how you define science. However, it would clearly benefit from science in the form of number-crunching computer technology – always bearing in mind the garbage-in-garbage-out caveat.
So, it’s not about ‘colonising’ – it’s about applying more rigour, and more questioning, to every area of human activity. And this is why ‘scientism’ is often a term of abuse used by the religious, and by ‘alternative medicine’ and ‘new age’ aficionados, who are always more interested in converts than critiques.
Returning to the interview, Pigliucci was asked first off whether it’s a common misconception among skeptics that there’s a thing called ‘the scientific method’:
Yes I think it is, and it’s actually a common misconception among scientists, which is more worrisome. If you pick up a typical science textbook… it usually starts out with a short section on the scientific method, by which they usually mean some version of… the nomological deductive model. The idea is that science is based firstly on laws…. the discovery of laws of nature, and ‘deductive’ means that mostly what is done is deduction, the kind of inferential reasoning that mathematicians and logicians do. But no scientists have ever used this model, and philosophers of science have debated the issue over the last century of so and now the consensus among such philosophers is that scientists do whatever the hell works….
(I’ve ‘smoothed out’ the actual words of Pigliucci here and elsewhere, but I believe I’ve represented his ideas accurately). I found this an extraordinary confession, by a philosopher of science, that after a century of theorising, philosophers have failed abysmally in trying to define the parameters of the scientific process. I’m not sure if Pigliucci understands the significance, for his own profession, of what he’s claiming here.
I have no problems with Pigliucci’s description that scientists ‘do what works’, though I think there’s a little more to it than that. Interestingly, I read a few books and essays on the philosophy of science way back in my youth, before I actually started reading popular science books and magazines, and once I plugged into the world of actual scientific experimentation and discovery I was rarely tempted to read that kind of philosophy again (mainly because scientists and science writers tend to do their own practical philosophising about the field they focus on, which is usually more relevant than the work of academic philosophers). I came up, years ago, with my own amateur description of the scientific process, which I’ll raise here to the status of Universal Law:
Scientists employ an open-ended set of methods to arrive at reliable and confirmable knowledge about the world.
So, while there’s no single scientific method, methodology is vital to good science, for hopefully obvious reasons. Arriving at this definition doesn’t require much in the way of philosophical training, so I rather sympathise with those, such as Neil Degrasse Tyson, Sam Harris and Richard Dawkins, who are targeted by Pigliucci as promoters or practitioners of scientism (largely because they feel much in the philosophy of science is irrelevant to their field). But first we really need to get a clearer view of what Pigliucci means by the term. Here’s his attempt at a definition:
Scientism is the notion that some people apply science where either it doesn’t belong or it’s not particularly useful. So, as betrayed by the ‘ism’, it’s an ideology. It’s the notion that it’s an all-powerful activity and that all interesting questions should be reducible to scientific questions. If they’re not, if science can’t tell you anything, then either the question is uninteresting or incoherent. This description of scientism is generally seen as a critique, though there are some who see scientism as a badge of honour.
Now I must say that I first came across scientism in this critical sense, while watching a collection of speeches by Christians and pro-religion philosophers getting stuck into ye olde ‘new atheism’ (see the references below). Their views were of course very defensive, and not very sophisticated IMHO, but scientism was clearly being used to shelter religious beliefs, which cover everything from morality to cosmology, from any sort of critique. There was also a lot of bristling about scientific investigations of religion, which raises the question, I suppose, as to whether anthropology is a science. It’s obvious enough that some anthropological analyses are more rigorous than others, but again, I wouldn’t lose any sleep over such questions.
But the beauty of the scientific quest is that every ‘answer’ opens up new questions. Good science is always productive of further science. For example, when we reliably learned that genes and their ‘mutations’ were the source of the random variation essential to the Darwin-Wallace theory of evolution, myriad questions were raised about the molecular structure of genes, where they were to be found, how they were transferred from parents to offspring, how they brought about replication and variation, and so forth. Science is like that, the gift that keeps on giving, turning ‘unknown unknowns’ into ‘known unknowns’ on a regular basis.
I’ve read countless books of ‘popular’ science – actually many of them, such as Robert Sapolsky’s Behave, James Gleick’s The information, and Oliver Morton’s Eating the the sun, are fiendishly complex, so not particularly ‘popular’ – as well as a ton of New Scientist, Scientific American and Cosmos magazines, and no mention has been made of ‘the scientific method’ in any of them, so Pigliucci’s claim that many scientists believe in some specific method just doesn’t ring true to me. But let me turn to some more specific critiques.
When Sam Harris wrote The Moral Landscape…he wrote in an endnote to the book that by science he meant any kind of reasoning that is informed by facts. Well, by that standard when my grandmother used to make mushroom risotto for me on Sundays, she was using science, because she was reasoning about what to do, based on factual experience. Surely that doesn’t count as science [laughing]… Even if you think of ‘food science’ as a science that’s definitely not what my grandmother was doing. It’s this attempt to colonise other areas of expertise and call them science…
In my view Pigliucci disastrously misses the point here. Making a delicious risotto is all about method, as is conducting an effective scientific experiment. It’s not metaphorical to say that every act of cooking is a scientific experiment – though of course if you apply the same method to the same ingredients, MacDonalds-style, the experimental element diminishes pretty rapidly. Once someone, or some group, work out how to make a delicious mushroom risotto (I’m glad Pigliucci chose this example as I’ve cooked this dish countless times myself!) they can set down the recipe – usually in two parts, ingredients and method – so that it can be more or less replicated by anyone. Similarly, once scientists and technologists work out how to construct a functioning computer, they can set down a ‘computer recipe’ (components and method of construction) so that it can be mass-produced. There’s barely any daylight between the two processes. The first bread-makers arguably advanced human technology as much as did the first computer-makers.
I have quite a bit more to say, so I’ll break this essay into two parts. More soon.
References – apart from the first and the last, these are all to pieces written by me.
Point of Inquiry interview with Massimo Pigliucci
Discussion on scientific progress and scientism, posted April 2019
A post about truth, knowledge and other heavy stuff, posted March 2013
politics and science need to mix, posted August 2011
On supervenience, posted January 2011
Roger Scruton and the atheist ‘fashion’, posted January 2011
a critique of Johnathan Ree’s contribution, posted January 2011
Marilynne Robinson tries her hand at taking on ‘new atheism’, posted January 2011
towards James Clerk Maxwell 3 – Benjamin Franklin and Coulomb’s Law
Canto: So we’ve been looking at electricity and magnetism historically, as researchers, scientists, thinkers, experimenters and so on have managed to piece these processes together and combine them into the one thing, electromagnetism, culminating in J C Maxwell’s equations…
Jacinta: Or going beyond those equations into the implications. But of course we’re novices regarding the science and maths of it all, so we should recommend that real students of this stuff should go to the Khan academy lectures, or Matt Anderson’s lectures for the real expert low-down. As will we. But we need to point out, if only to ourselves, that what we’re trying to get our heads around is really fundamental stuff about existence. Light, which is obviously fundamental to our existence, is an electromagnetic wave. So, think magnetism, think electricity, and think light.
Canto: Right, so we’re going back to the eighteenth century, and whatever happens after Hauksbee and Polinière.
Jacinta: Well, scientists – or shall we say physical scientists, the predecessors of modern physicists – were much influenced throughout the eighteenth century by Newton, in particular his inverse square law of gravity:
Newton saw gravity as a force (F), and formulated the theory that this force acted between any two objects (m1 and m2 – indicating their masses) in a direct line between their respective centres of mass (r being the length of that line, or the distance between those centres of mass). This force is directly proportional to the product of the two masses and inversely proportional to the distance. As to G, the gravitational constant, that’s something I don’t get, as yet. Anyway, the success of Newton’s theory, especially the central insight that a force diminishes, in a precise way, with distance, affected the thinking of a number of early physical scientists. Could a similar theory, or law (they didn’t think in terms of theory then) apply to electrical forces? Among those who suspected as much were the mathematician Daniel Bernoulli, who made major contributions to fluid dynamics and probability, and Alessandro Volta, who worked on electrical capacitance and storage, the earliest batteries.
Canto: And Joseph Priestley actually proposed an inverse square law for electricity, but didn’t work out the details. Franz Aepinus and Benjamin Franklin were also important 18th century figures in trying to nut out how this force worked. All of this post-Newtonian activity was putting physical science on a more rigorous and mathematical footing. But before we get to Coulomb and his law, what was a Leyden Jar?
Jacinta: Leyden jars were the first capacitors. They were made of glass. This takes us back to the days of Matthias Bose earlier in the 18th century, and even back to Hauksbee. Bose, a professor of natural philosophy at the University of Wittenberg, worked with and improved Hauksbee’s revolving glass-globe machine to experiment with static electricity. He added a metal ‘prime conductor’ which accumulated a higher level of static charge, and gave spectacular public demonstrations of the sparks he created, using them to set alcohol alight and to create ‘beatification’ effects on a woman wearing a metal helmet. All great japes, but it promoted interest in electricity on the continent. The trick with alcohol inspired another experimenter, Jurgen von Kleist, to invent his Leyden jar, named for Kleist’s university. It was a glass container filled with alcohol (or water) into which was suspended a metal rod or wire, connected to a prime conductor. The fluid collected a great deal of electric charge, which turned out to be very shocking to anyone who touched the metal rod. Later Leyden jars used metal foil instead of liquid. These early capacitors could store many thousands of volts of electricity.
Canto: At this time, in the mid-eighteenth century, nobody was thinking much about a use for electricity, though I suppose the powerful shocks experienced by the tinkerers with Leyden jars might’ve been light-bulb moments, so to speak.
Jacinta: Well, take Ben Franklin. He wasn’t of course the first to notice that electrostatic sparks were like lightning, but he was possibly the first to conduct experiments to prove the connection. And of course he knew the power of lightning, how it could burn down houses. Franklin invented the lightning rod – his proudest invention – to minimise this damage.
Canto: They’re made of metal aren’t they? How do they work? How did Franklin know they would work?
Jacinta: Although the details weren’t well understood, it was known in Franklin’s time that some materials, particularly metals (copper and aluminium are among the best), were conductors of electricity, while others, such as glass, were insulators. He speculated that a pointed metal rod, fixed on top of buildings, would provide a focal point for the electrical charge in the clouds. As he wrote: “The electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike….” He also had at least an inkling of what we now call ‘grounding’, as per this quote about the design, which should use “upright Rods of Iron, made sharp as a Needle and gilt to prevent Rusting, and from the Foot of those Rods a Wire down the outside of the Building into the Ground”. He was also, apparently the inventor of the terms negative and positive for different kinds of charge.
Canto: There are different kinds of charge? I didn’t know that.
Jacinta: Well you know of course that a molecule is positively charged if it has more protons than electrons, and vice versa for negative charge, but this molecular understanding came much later. In the eighteenth century electricity was generally considered in terms of the flow of a fluid. Franklin posited that objects with an excess of fluid (though he called it ‘electrical fire’) were positively charged, and those with a deficit were negatively charged. And those terms have stuck.
Canto: As have other other electrical terms first used by Franklin, such as battery, conductor, charge and discharge.
Jacinta: So let’s move on to Charles-Augustin De Coulomb (1736-1806), who was of course one of many scientists and engineers of the late eighteenth century who were progressing our understanding and application of electricity, but the most important one in leading to the theories of Maxwell. Coulomb was both brilliant and rich, at least initially, so that he was afforded the best education available, particularly in mathematics…
Canto: Let me write down Coulomb’s Law before you go on, because of its interesting similarity to Newton’s inverse-square gravity law. It even has one of those mysterious ‘constants’:
where F is the electrostatic force, the qs are particular magnitudes of charges, and r is the distance between those charges.
Jacinta: Yes, the Coulomb constant, ke, or k, is a constant of proportionality, as is the gravitational constant. Hopefully we’ll get to that. Coulomb had a varied, peripatetic existence, including a period of wise retirement to his country estate during the French revolution. Much of his work involved applied engineering and mechanics, but in the 1780s he wrote a number of breakthrough papers, including three ‘reports on electricity and magnetism’. He was interested in the effect that distance might have on electrostatic force or charge, but it’s interesting that these papers placed electricity and magnetism together. His experiments led him to conclude that an inverse square law applied to both.
Canto: I imagine that these constants required a lot of experimentation and calculation to work out?
Jacinta: This is where I really get lost, but I don’t think Coulomb worked out the constant of proportionality, he simply found by experimentation that there was a general law, which he more or less stated as follows:
The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.
The force is along the straight line joining them. If the two charges have the same sign, the electrostatic force between them is repulsive; if they have different signs, the force between them is attractive.
It seems the constants of proportionality are just about units of measurement, which of course were different in the days of Coulomb and Newton. So it’s just about measuring stuff in modern SI units using these laws. It’s about conventions used in everyday engineering, basically. I think.
Canto: Equations like these have scalar and vector forms. What does that mean?
Jacinta: Basically, vector quantities have both magnitude and direction, while scalar quantities have magnitude only. The usual example is speed v velocity. Velocity has magnitude and direction, speed only has magnitude. Or more generally, a scalar quantity has only one ‘dimension’ or feature to it in an equation – say, mass, or temperature. A vector quantity has more than one.
Canto: So are we ready to tackle Maxwell now?
Jacinta: Hell, no. We have a long way to go, with names like Gauss, Cavendish and Faraday to hopefully help us along the path to semi-enlightenment. And I think we need to pursue a few of these excellent online courses before we go much further.
References
Khan academy physics (160 lectures)
Matt Anderson physics (191 lectures)
https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation
https://www.britannica.com/technology/Leyden-jar
http://www.americaslibrary.gov/aa/franklinb/aa_franklinb_electric_1.html
http://www.revolutionary-war-and-beyond.com/benjamin-franklin-and-electricity-letters.html
https://en.wikipedia.org/wiki/Coulomb_constant
https://www.britannica.com/biography/Charles-Augustin-de-Coulomb
https://www.britannica.com/science/Coulombs-law
https://en.wikipedia.org/wiki/Coulomb%27s_law
kin selection – some fascinating stuff
Canto: So we’ve done four blogs on Palestine and we’ve barely scratched the surface, but we’re having trouble going forward with that project because, frankly, it’s so depressing and anger-inducing that it’s affecting our well-being.
Jacinta: Yes, an undoubtedly selfish excuse, but we do plan to go on with that project – we’re definitely not abandoning it, and meanwhile we should recommend such books as Tears for Tarshiha by the Palestinian peace activist Olfat Mahmoud, and Goliath by the Jewish American journalist Max Blumenthal, which highlight the sufferings of Palestinian people in diaspora, and the major stresses of trying to exist under zionist monoculturalism. But for now, something completely different, we’re going to delve into the fascinating facts around kin selection, with thanks to Robert Sapolski’s landmark book Behave.
Canto: The term ‘kin selection’ was first used by John Maynard Smith in the early sixties but it was first mooted by Darwin (who got it right about honey bees), and its mathematics were worked out back in the 1930s.
Jacinta: What’s immediately interesting to me is that we humans tend to think we alone know who our kin are, especially our extended or most distant kin, because only we know about aunties, uncles and second and third cousins. We have language and writing and record-keeping, so we can keep track of those things as no other creatures can. But it’s our genes that are the key to kin selection, not our brains.
Canto: Yes, and let’s start with distinguishing between kin selection and group selection, which Sapolsky deals with well. Group selection, popularised in the sixties by the evolutionary biologist V C Wynne-Edwards and by the US TV program Wild Kingdom, which I remember well, was the view that individuals behaved, sometimes or often, for the good of the species rather than for themselves as individuals of that species. However, every case that seemed to illustrate group selection behaviour could easily be interpreted otherwise. Take the case of ‘eusocial’ insects such as ants and bees, where most individuals don’t reproduce. This was seen as a prime case of group selection, where individuals sacrifice themselves for the sake of the highly reproductive queen. However, as evolutionary biologists George Williams and W D Hamilton later showed, eusocial insects have a unique genetic system in which they are all more or less equally ‘kin’, so it’s really another form of kin selection. This eusociality exists in some mammals too, such as mole rats.
Jacinta: The famous primatologist Sarah Hrdy dealt something of a death-blow to group selection in the seventies by observing that male langur monkeys in India commit infanticide with some regularity, and, more importantly, she worked out why. Langurs live in groups with one resident male to a bunch of females, with whom he makes babies. Meanwhile the other males tend to hang around in groups brooding instead of breeding, and infighting. Eventually, one of this male gang feels powerful enough to challenge the resident male. If he wins, he takes over the female group, and their babies. He knows they’re not his, and his time is short before he gets booted out by the next tough guy. Further, the females aren’t ovulating because they’re nursing their kids. The whole aim is to pass on his genes (this is individual rather than kin selection), so his best course of action is to kill the babs, get the females ovulating as quickly as possible, and impregnate them himself.
Canto: Yes, but it gets more complicated, because the females have just as much interest in passing on their genes as the male, and a bird in the hand is worth two in the bush…
Jacinta: Let me see, a babe in your arms is worth a thousand erections?
Canto: More or less precisely. So they fight the male to protect their infants, and can even go into ‘fake’ estrus, and mate with the male, fooling the dumb cluck into thinking he’s a daddy.
Jacinta: And since Hrdy’s work, infanticide of this kind has been documented in well over 100 species, even though it can sometimes threaten the species’ survival, as in the case of mountain gorillas. So much for group selection.
Canto: So now to kin selection. Here are some facts. If you have an identical twin your genome is identical with hers. If you have a full sibling you’re sharing 50% and with a half-sibling 25%. As you can see, the mathematics of genes and relatedness can be widened out to great degrees of complexity. And since this is all about passing on all, or most, or some of your genes, it means that ‘in countless species, whom you co-operate with, compete with, or mate with depends on their degree of relatedness to you’, to quote Sapolsky.
Jacinta: Yes, so here’s a term to introduce and then fairly promptly forget about: allomothering. This is when a mother of a newborn enlists the assistance of another female in the process of child-rearing. It’s a commonplace among primate species, but also occurs in many bird species. The mother herself benefits from an occasional rest, and the allomother, more often than not a younger relation such as the mother’s kid sister, gets to practice mothering.
Canto: So this is part of what is called ‘inclusive fitness’, where, in this case, the kid gets all-day mothering (if of varying quality) the kid sister gets to learn about mothering, thereby increasing her fitness when the time comes, and the mother gets a rest to recharge her batteries for future mothering. It’s hopefully win-win-win.
Jacinta: Yes, there are negatives and positives to altruistic behaviour, but according to Hamilton’s Rule, r.B > C, kin selection favours altruism when the reproductive success of relatives is greater than the cost to the altruistic individual.
Canto: To explain that rule, r equals degree of relatedness between the altruist and the beneficiary (aka coefficient of relatedness), B is the benefit (measured in offspring) to the recipient, and C is the cost to the altruist. What interests me most, though, about this kin stuff, is how other, dumb primates know who is their kin. Sapolsky describes experiments with wild vervet monkeys by Dorothy Cheney and Robert Seyfarth which show that if monkey A behaves badly to monkey B, this will adversely affect B’s behaviour towards A’s relatives, as well as B’s relatives’ behaviour to A, as well as B’s relatives’ behaviour to A’s relatives. How do they all know who those relatives are? Good question. The same researchers proved this recognition by playing a recording of a juvenile distress call to a group of monkeys hanging around. The female monkeys all looked at the mother of the owner of that distress call to see what she would do. And there were other experiments of the sort.
Jacinta: And even when we can’t prove knowledge of kin relations (kin recognition) among the studied animals, we find their actual behaviour tends always to conform to Hamilton’s Rule. Or almost always… In any case there are probably other cues, including odours, which may be unconsciously sensed, which might aid in inclusive fitness and also avoiding inbreeding.
Canto: Yes and It’s interesting how this closeness, this familiarity, breeds contempt in some ways. Among humans too. Well, maybe not contempt but we tend not to be sexually attracted to those we grow up with and, for example, take baths with as kids, whether or not they’re related to us. But I suppose that has nothing to do with kin selection. And yet…
Jacinta: And yet it’s more often than not siblings or kin that we have baths with. As kids. But getting back to odours, we have more detail about that, as described in Sapolski. Place a mouse in an enclosed space, then introduce two other mice, one unrelated to her, another a full sister from another litter, never encountered before. The mouse will hang out with the sister. This is called innate recognition, and it’s due to olfactory signatures. Pheromones. From proteins which come from genes in the major histocompatibility complex (MHC).
Canto: Histowhat?
Jacinta: Okay, you know histology is the study of bodily tissues, so think of the compatibility or otherwise of tissues that come into contact. Immunology. Recognising friend or foe, at the cellular, subcellular level. The MHC, this cluster of genes, kicks off the production of proteins which produce pheromones with a unique odour, and because your relatives have similar MHC genes, they’re treated as friends because they have a similar olfactory signature. Which doesn’t mean the other mouse in the enclosure is treated as a foe. It’s a mouse, after all. But other animals have their own olfactory signatures, and that’s another story.
Canto: And there are other forms of kin recognition. Get this – birds recognise their parents from the songs sung to them before they were hatched. Birds have distinctive songs, passed down from father to son, since its mostly the males that do the singing. And as you get to more complex species, such as primates – though maybe they’re not all as complex as some bird species – there might even be a bit of reasoning involved, or at least consciousness of what’s going on.
Jacinta: So that’s kin selection, but can’t we superior humans rise above that sort of thing? Australians marry Japanese, or have close friendships with Nigerians, at least sometimes.
Canto: Sometimes, and this is the point. Kinship selection is an important factor in shaping behaviour and relations, but it’s one of a multiple of factors, and they all have differential influences in different individuals. It’s just that such influences may go below the level of awareness, and being aware of the factors shaping our behaviour is always the key, if we want to understand ourselves and everyone else, human or non-human.
Jacinta: Good to stop there. As we’ve said, much of our understanding has come from reading Sapolsky’s Behave, because we’re old-fashioned types who still read books, but I’ve just discovered that there’s a whole series of lectures by Sapolsky, about 25, on human behaviour, which employs the same structure as the book (which is clearly based on the lectures), and is available on youtube here. So all that’s highly recommended, and we’ll be watching them.
References
R Sapolski, Behave: the biology of humans at our best and worst. Bodley Head, 2017
https://www.britannica.com/science/animal-behavior/Function#ref1043131
https://en.wikipedia.org/wiki/Kin_selection
https://en.wikipedia.org/wiki/Eusociality
is this the best use of journalism?: attn Katie McBride and Outline magazine
Rat Park, in colour
Jacinta: Now we’re going to do something slightly unpleasant but wholly necessary: take someone to task, as teachers must occasionally do.
Canto: Yes, it relates to a previous post, a recent one, about Rat Farm and the war on drugs.
Jacinta: In writing that post we happened upon an article entitled ‘This 38-year-old study is still spreading bad ideas about addiction” – which kind of shocked me with its provocative title. It was written by Katie MacBride and published by Outline, an online magazine. I only skimmed the article at the time, bemused to find the Rat Park experiment still creating such negative vibes after all these years, but some obvious problems in the article stood out, even on the most cursory reading, so I’ve decided to revisit it with a more careful analysis, with Canto’s help.
Canto: Well the first red flag with the article comes with the first words, before even the title. Pop science. In other words, this article, or rather its subject, should be filed in the category of ‘pop science’, as opposed to real science. This is designed to instil prejudice in the reader from the outset, and is clearly a cheap trick.
Jacinta: Yes, and for an immediate antidote to this kind of cheapsterism, I’d advise anyone to read the Wikipedia article on the rat park experiment, which is calmly and reasonably presented, as is usual. And let me here heap praise on Wikipedia for its general reliability, its objectivity and its pro-science approach. It’s one of the greatest gifts the internet has provided to our world, IMHO.
Canto: The next red flag comes with the title – ’38 years old and still spreading bad ideas’…. As if the date of the study is relevant. There are a number of landmark psychology studies even older than Bruce Alexander’s Rat Park, and also ‘flawed’ – of which more later, – which continue to resonate today for obvious reasons…
Jacinta: Yes, for example Stanley Milgram’s electric shock experiments, over fifty years ago now, and the Stanford Prison experiment of 1971. These, and Alexander’s Rat Park experiment, deserve to be regarded as landmark pieces of work because they make you think. And they often overturn previous thinking. They shake our complacency.
Canto: And what about the latter part of the title, that Alexander’s work is still spreading bad ideas?
Jacinta: It’s interesting that she claims this, considering that the main reason Alexander embarked on this study was to combat bad ideas – particularly the war on drugs itself, and the prevailing view, promoted by the likes of Harry Anslinger and his zero tolerance approach to drugs such as cannabis and cocaine, that use of these drugs led inevitably to a kind of madness that was extremely harmful to self and others. Remember the rat adverts of the time, which showed rats dropping dead after regularly imbibing morphene-laced water, with the message ‘this could happen to you’.
Canto: Yes, and the rats may well have been choosing the drug over plain water because, like many lab rats of the time – hopefully things have changed – the conditions they were kept in made their life something of a living hell. What Alexander’s experiment showed was that, given a far more enriched environment, rats made far less simplistic and self-destroying choices. That’s all. So how could this be a ‘bad idea?’
Jacinta: MacBride doesn’t say. But to be fair, Alexander’s thesis may have been that opiates aren’t addictive at all, which is not what his results showed – they showed that environment matters hugely in respect to the willingness to get hooked on drugs. And that’s a really really important finding, not a ‘bad idea’.
Canto: And we’re still on the title of MacBride’s essay, which is followed by a tiny summary remark, ‘The Rat Park study was flawed and its findings have been oversimplified, but it keeps getting cited.’ Any comments?
Jacinta: Yes – as a regular listener to the podcasts of the Skeptic’s Guide to the Universe (SGU) over the years, as well as a reader of Ben Goldacre and other science-based critics of medical/psychological studies and experiments, I can safely say that every piece of research or experimentation, since the dawn of time, is flawed. Or imperfect. Or limited. Some more than others. of course. So to say the study is flawed is to say nothing at all. Every episode of SGU, and I’ve listened to hundreds, features one piece of published research or other, which Steve Novella picks to pieces to determine whether it’s very or mildly interesting, or a piece of rubbish, but even with the best study, the mantra is generally ‘needs more research’. So a critic needs to show how an experiment is flawed, and how those flaws affect the results. And MacBride’s effort to do this is pretty abysmal.
Canto: Okay, before we examine that effort, I’d like to quote something from early on in MacBride’s article:
The Rat Park study undermined one popular misconception about addiction, that chemistry of drugs is the single most important factor in addiction. But instead of pushing the popular understanding forward, it merely replaced that misconception with a new one: that environment is the most important factor.
What do you make of that? Do you think it a fair description of the study?
Jacinta: It’s an odd description, or mis-description, of the study. The first sentence you quoted isn’t problematic. The study did undermine the idea that it was all about chemistry. Or rather it would have, had anyone paid attention to it. It should have, as MacBride implies, but instead of then regretting that the study didn’t have any impact, she presents it as deserving of oblivion. It doesn’t make much sense.
Canto: The quote claims that it’s a misconception that environment is the most important factor in drug addiction. Do you agree?
Jacinta: I don’t know if it’s the most important factor, but it’s obviously an important factor, and the Rat Park experiment provided strong evidence for this. It seems MacBride is confusing Alexander’s possible claims or commentary on the study with the study itself. The study doesn’t prove that environment is the most important factor, but it certainly makes you think about addiction in a very different way from the horrific but dumb rat ads that prompted it. It makes you think, as all good studies do, and that’s something MacBride seems extremely reluctant to admit. And I wonder why.
Canto: But MacBride does provide cogent criticisms of the study, doesn’t she?
Jacinta: Well, she quotes one particular critique of the study, by a Dr Sam Snodgrass, who found that the Rat Park environment, in which rats were no longer isolated and therefore mated, as rats are wont to do, would have rendered the findings questionable. According to Snodgrass, “You can’t have one group of subjects mating and with pups and compare it to a group that doesn’t engage in these behaviors and say that the difference between the two groups is caused by environmental differences.” But I beg to differ. An environment in which you’re isolated and unable to have sex is obviously very different from an environment in which you breed as normal – especially for rats. As to the rat pups ruining the experiment, I think if you looked closely at any rat study in which rats get to live together and breed, the actual experiment would be more messy than the published results indicate, but I doubt the problems would be so great as to invalidate those results.
Canto: And what about attempts to replicate the experiment?
Jacinta: Well there seem not to have been enough of them, and that’s not Alexander’s fault. Above all, similar experiments should have been conducted with different drugs and different concentrations etc. And of course rats aren’t humans, and it’s hard to bridge that gap, especially these days, as lab testing of other non-human animals (and rats too) is increasingly frowned upon, for good reason. I note that MacBride briefly mentions that others did replicate Alexander’s results, but she chooses to focus almost wholly on those who found differences. She’s also quite brief in describing the obvious parallel, presented in much greater detail in Johann Hari’s Chasing the scream, of American soldiers taking heavily to heroin in the alienating environment of Vietnam and giving them up on their return to what was for them an obviously more enriched environment. The facts were startling – 20 time the heroin addiction in Vietnam, as MacBride admits – but not much is made of them, as she is more concerned to pour cold water on Rat Park, so to speak.
Canto: Yes it’s strange – MacBride admits that the war on drugs has been an abject failure, but her obsession with criticising Rat Park prevents her from carrying through on that with, for example, the alternatives to this American approach in Europe. She mentions the again startling fact, reported by the Brookings Institute, that the combined hardcore user rate for hard drugs was approximately 4 times higher in the US than in Europe, after decades of the US war on drugs, but fails to note that the Rat Park experiment was one of the main inspirations in implementing more humane and vastly more successful policies, not only in Europe but, more recently, in some US states.
Jacinta: Yes MacBride is clearly concerned to get everyone’s facts straight on the opioid epidemic that’s currently gripping the US, and about which I honestly know little, but I think she has gone overboard in seeking to vilify the Rat Park study, which surely has little to do with that epidemic. The Rat Park experiment hardly promotes drug-taking; what it does strongly suggest, as does Johann Hari’s book, is that environment is one of the most important factors in determining a person’s willingness to escape into drugs. My own personal experience tallies with that, having been brought up in a depressed and disadvantaged region, hard-hit in the seventies by economic recession, and watching the illicit drug trade take off around me, as houses and gardens became more and more derelict.
Canto: Yes, it’s hard to understand why she’s focusing so negatively on Rat Park, when the problem is really one of interpretation, insofar as there is a problem. And I don’t know how it relates negatively to the opioid crisis. Maybe we should find out more about this crisis, and do a follow-up?
Jacinta: Maybe, but it’s so hard trying to fix the world’s problems… but of course that’s what we’re here for…