ISTM that human technological and cultural evolution swamps genetic evolution every time. That’s why a species that evolved in the savannas of Africa can exist above the Arctic Circle - and even in space. We don’t need to evolve fur if we develop clothes. We don’t need to grow claws - a knife works better. And cultural change spreads (in an age of mass communication) in a matter of days or hours - not generations.
And now that we have begun to engineer genes, all bets are off.
I believe it is literally true that humans represent the next stage of evolution.
I attended a lecture by (IIRC) John Robinson, a co-discoverer of Australopithecus africanus, who argued this. I have been convinced ever since.
There’s also a very interesting book out by Steven Johnson called Everything Bad is Good For You. While some of his points are a bit simplistic, and he does a good job setting up certain strawmen (especially on the section on video games; he completely mischaracterizes his opponents’ arguments), he also makes a convincing argument that humans are getting smarter and smarter with each generation.
The most essential problem with the “dysgenic pressure” argument is that it makes the assumption that human intelligence is mainly based upon genetics. While there is some truth that there is correlation between the intelligence of parents and their children, there is much more evidence that someone’s intelligence is determined by upbringing and culture. Johnson’s argument is that our popular culture has gotten more complex as time has progressed, and therefore children being brought up now learn how to assimliate knowledge, prioritize information, and process stimuli faster than their parents. So, even the “slow” children are better at understanding complex plots and stories delivered at a rapid pace than their parents, or even “smart” adults.
Highly dubious, if only for its oversimplication. Even after we start genetically engineering ourselves, we’ll still be subject to natural selection, and our entire species could easily be wiped out by some environmental catstrophy or some new disease.
Nitpick: Robinson found some A. africanus fossils in the 40s, but I’ve never heard him called a co-discoverer of that species. Raymond Dart discovered the famous Taung child skull in 1924 and gave it the name A. africanus. If anyone might share the glory with Dart it would be Robert Broom, not Robinson (who was born in 1923 and would have been only 1 year old when the Taung skull was discovered).
If people who could not have survived in the past are now able to survive, how can that not be a good thing? The objective of any species (if they can be said to have one) is to survive. On the whole, we are doing a better job of that than we have ever done before. If “weaker” people survive, that’s exactly the idea. We want our conditions to be less harsh.
I’m not sure that superstition is the right word, but I do think that people who think in terms of dysgenics are looking at it the wrong way.
This is where is argument is particularly weak, IMO, because being able to avoid selection against physical disability is one of the great boons of civilization. Consider Stephen Hawking: in an earlier age, he’d have been left for the wolves, or set afloat on an ice floe, or something. But because his physical disadvantages can be managed to the extent that he can survive and prosper, his real advantage - his incredible intellect - can be exploited to the advancement of the entire species. Sure, if there’s a catastrophic failure of society and we’re reduced to living in caves and beating eachother over the head with clubs, he’s SOL, but I think that a society nurtures intellects such as Hawking’s is less likely to revert to a stage where it cannot support physiologies such as Hawking’s.
Yep. The more diverse the gene pool, the better. Even if those “weak” individuals aren’t technically pulling their weight in the society, who knows what genes they might have that will come in handy in the future. ANd if there are “smart genes”, they aren’t necessarily being lost just because there are more “stupid genes” out there.
It doesn’t mean we are exempt from extinction, but that we are now evolving culturally rather than biologically.
IIRC, Robinson was Broom’s assistant. [Broom, R. and J.T. Robinson. 1949 “A new mandible of the ape-man Plesianthropus transvaalensis.” In American Journal of Physical Anthropology, vo. 7, pp. 123-127.
I surprised that this thread has gone this long with no mention of the Flynn effect:
Regardless of what your theories say should happen to the average I.Q. because of dysgenic pressure, it hasn’t happened. On the contrary, since the first general use of I.Q. tests in the 1920’s, the average I.Q. has risen in every country where there has been a general use of I.Q. tests. On the average, the average I.Q. has risen by about three points a decade. Now, although this statistic is not much disputed, its significance is greatly disputed. If one wants to dispute it, it would seem that then there is no easy way to measure the average I.Q. and perhaps no easy way to measure any individual’s I.Q. So what’s the point of discussing dysgenic pressure when the only good measurement of its supposed effect says that it isn’t having any effect and that in fact the only measurable trend is in the opposite direction?
Do you really believe the IQ of a population is measurable. These tests are concocted and remade endlessly. It is for the benefit of those on topand who administer them. When will a test say that our polititicians are getting stupider. This I believe.
Evolution is a long process. A snapshot of a day ,week month or year provide no useful information. It just gives academics something to do.
Plus society needs laborers and warriors. They must be able to accept training and control.
As I said, “there is no easy way to measure the average I.Q. and perhaps no easy way to measure any individual’s I.Q.” So I’ve already said that I don’t know if it’s possible even to measure an individual’s I.Q., let alone the average I.Q. of an entire country. My point, once again, is the following:
The results of the best tests of average I.Q. (assuming that it actually measures anything) is that average I.Q. is rising, which is the exact opposite of what a theory of dysgenic pressure would predict.
Therefore one of the following is true:
(1) Dysgenic pressure is having no effect on average I.Q., assuming that dysgenic pressure even exists.
(2) We can’t accurately measure average I.Q. Perhaps we can’t even accurately measure a single person’s I.Q.
I’m not drawing any dichotomies. Our biological evolution is drowned out by the pace of our cultural and technological change, because we are far less subject to selection pressure.
Children who would have died a thousand years ago survive to reproduce. Education pushes IQ upwards faster than selective reproductive success. Etc.
Certainly our cultural evolution proceeds at a faster clip than our biological evolution, but the former certainly doesn’t “drown out” the later. That’s also different from your original statement that we are now no longer evolving biologically. That is demostrably untrue.
All you need do is look at the effects of disesaes (small pox on Native Americans, AIDS on certain populations today). I think you’re focusing too much on superficial physcial triats and ignoring things like our immune system, which certaily is quite different from our ancestors of 10,000 years ago.
Well, “Eve” existed before any of the extant races (or ethnic groups) evolved, so that pretty much takes care of your assertion right there. However, we also know, for example, that the gene for lactose tolerance evolved in certain human populations (perhaps twice, independently) in the last 6,000 years or so.
There is no reason that “Eve” had to be a member of the species Homo sapiens. Had we not passed thru an evolutionary bottleneck (or two), she could very well have belonged to an earlier species-- in fact, she amost did, given that she existed about 150k years ago.
There are all kinds of known mutations of genes which can determine mental ability in a negative sense. They may have systemic effects plus neurodegeneration as a prominant symptom of the syndrome associated with the disease, or their effects may be most pronounced in or limited to the CNS. PKU, Tay Sach’s, Alzheimer’s, Huntington’s, just to give some obvious examples. Every once in a while someone publishes a paper describing some-or-other gene that may be implicated in determining g (I’d rather not get into a discussion about the very existence of g, thanks), often genes associated with glutamate function (perhaps directly at the receptor level, or maybe indirectly, such as some recent work on dysbindin-1). As the glutamate/GABA system is often implicated in schizophrenia as well, it’s interesting to speculate about the biological origins of that that age-old association of genius and madness.
There’s likely not a single gene that can play a large role in conferring superior intelligence, but that “general intelligence” is to a great degree a multiallelic inherited trait is not so controversial a notion, and it appears we’re zeroing in on some of the genes (or, at least, common haplotypes) that are associated with high IQ.
A current Scientific American special edition on “Becoming Human” has an interesting article on why many genetic diseases persist in the gene pool. It’s because while having two copies of the gene can be fatal, having only one copy apparently can provide significant benefits.
The Hbs gene which causes sickle-cell anemia when you have two copies provides protection from malaria with only one copy. The CFTR cystic fibrosis gene protects against diarrhea if you only have one copy, while the FV Leiden gene which causes thrombosis with two copies increases resistance to blood sepsis with only one copy.
Another article in the same issue discusses the significant role that social interaction plays in developing the use of intelligence in apes, reinforcing the arguments of Der Trihs and John Corrado above.
