A while ago, economist Paul Krugman described the institutional loss of knowledge in the discipline of economics:
And the latter group, the equilibrium macro side, was so convinced of the logical correctness of its position that schools dominated by that view stopped teaching demand-side economics. (Schools dominated by new Keynesians, on the other hand, did teach real business cycle theory.) I haven’t been able to dig up the quote, but somewhere along the line Ed Prescott declared that his students wondered who Keynes was, because he was never mentioned in their courses.
And those trained according to this dogma were and are utterly ignorant of what Keynes, or modern Keynesians, have to say. They know that Keynesianism is stupid nonsense, because that’s what they remember having been told. But they don’t actually know why they’re supposed to believe that; the serious debates the profession had in the 70s about the microfoundations of inflation and unemployment theory are lost in the mist.
And as a result we have the spectacle of well-known economists offering what they think are profound arguments, but are actually long-refuted fallacies. Most important is the “Treasury view” that government spending can’t affect demand. But there’s also the astonishing belief that Ricardian equivalence means that consumer spending automatically falls to offset even a temporary increase in government spending, which seem to be part of that Poole quote. (New Keynesian models in which consumers fully anticipate future taxes still leave room for fiscal policy — but they don’t know that.)
And the sad thing is that all of this matters. Our ability as a nation to respond to the current economic crisis is being seriously hampered by the gratuitous ignorance of many of our economists.
The post made me wonder what concepts are being neglected or not even taught in biology (I’m thinking about the graduate school level). I’ve come up with three things in evolutionary biology/genetics that I think we’re not teaching as much as we should:
- The neutralist/selectionist debate. While students, at least in evolutionary biology, are taught neutral theory, I think the history is important. I hear a lot of genomics seminars/talks and I keep hearing that genes found in one species and not another determine ecological differences between the two species. I think we’re going to end up replay the neutralist/selectionist debate (for at least the third time), this time regarding genome structure (i.e., gene order, gene number, gene presence and absence.
- Norms of reaction and phenotypic plasticity. The norm of reaction is the pattern of phenotypic expression of a single genotype across a range of environments. Some genotypes might have different trait values (e.g., plant height) in certain environments, but, in other environments, genotypes might not differ at all (or the differences could even reverse; genotype A is taller than genotype B in environment X, but shorter in environment Y).
A lot of the discussions about the genetic basis of human traits seem to ignore this (an aside: twin studies simply remove the issue of environmental effects to the level of twin pairs, as opposed to individuals). Evolutionary psychology is even worse (although ignoring norms of reaction and phenotypic plasticity isn’t the worse thing about evo psych).
- Heritability estimates are always environment-dependent. When the edifice of quantitative genetics was being developed (by Falconer and others), it relied heavily on agriculture (and agriculture was the main ‘consumer’). This provided a large body of empirical knowledge that made it impossible to forget that even small differences in environment can affect the strength of heritability estimates (as well as the type of correlations between traits–but that’s another argument all together). Human genetics in particular, which often does is piss-poor job of quantifying the environment (or incorrectly assumes that twin studies control for this effect) seems, to me, vulnerable to this.
That’s my list. So what things in biology (and it doesn’t have to be evolutionary biology) do you think we’ve forgotten to our loss?