Evolutionary changes in modern humans due to increased dependance on technology?

Replies to This Discussion

Permalink Reply by ROMAN ROMACH on December 3, 2010 at 4:27pm

Besides the effect of technology on our evolution there are also cultural and environmental factors. For example, because of dairy farming almost everyone in Sweden and Denmark can digest fresh milk, but very few can in Africa and China. There is more resistance to the virus causing Lassa fever; more resistance to malaria in some Mideastern populations, and 10% of the European population showing immunity to HIV.

Although societal mores and and medical advances now make it easier for defective genes to increase in the population, I think it is premature to predict the evolutionary "weakening" of Homo sapiens. We can make generalizations only about specific, stable populations in specific geographical areas.

Although technology has influenced our evolution, I believe other factors will eventually play a greater role:
The homogenization of the world population
Pandemics
Gradual climate change
Rapid climate change
Catastrophic geological events
Large-scale drought
Overpopulation
Increased UV radiation
Big things falling from the sky

Permalink Reply by Joseph P on December 3, 2010 at 6:06pm

Cell phones and wireless internet signals

Permalink Reply by Jack Harkness on December 3, 2010 at 7:14pm

As a layman in this field I would think that survival to breed would be unaffected by technological gadgets, so would likely have little effect on human evolution on average. However the ability to find a suitable partner has increased with the internet so I think more intelligent people will find each other easier than in the past. Could this lead to an intellectual elite strain of humans developing in parallel to a normal strain? As labour saving devices and technologies advance the lower end of the human intellectual spectrum becomes obsolete, out of work couch potatoes. Better social support in richer parts of the world allows them to breed so is it possible that an intellectually stratifying evolutionary phase could develop. Add to this the high birth rate in third world countries where poor nutrition, education, etc, lead to stunted intellectual growth compared to low birth rates in first world countries where better nutrition, education, etc, leads to higher intellectual growth and the elements are in place for this to add to the stratification. Could this result in two or more sub species of humans developing differentiated by intelligence? Is Japan a less war like nation now because so many of the most warlike males died in the war? Will Muslim suicide bombers become harder to find as less with these tendencies reach breeding age? I think we are still evolving and cyborg developments coupled with space exploration may accelerate it physically as well as mentally.

Permalink Reply by ROMAN ROMACH on December 3, 2010 at 10:19pm

Technology allows EVERYONE to reproduce, not just the "fittest". So, yes, it very much has had an effect on human evolution.

Your assuming that only smart people produce smart babies. There is no correlation between smart parents and smart babies or dumb parents and dumb babies. (And does everyone want to marry their intellectual equal?) So, there has never been an intellectually elite strain of humans (despite Hitler's efforts.), other than that based on education.

Poor nutrition does effect physical and mental growth, but acquired traits are not passed on from one generation to another. Since smartness cannot be passed on, I don't see our species splitting into two branches on that basis. In fact, technological advances allow all of us the same chance of passing along our genes.

The Japanese are less warlike because after WWII, their constitution limits their military to self-defence only.

There is no suicide-bomber gene. People are simply coerced or brainwashed.

Permalink Reply by Taran Rampersad on December 3, 2010 at 10:34pm

Good points. Reminded me of how I was considering whether or not socioeconomics has taken a more aggressive role in evolution of our species. While there are people who try to eat better and receive better healthcare at lower income levels, those at higher income levels have the potential for better foods and healthcare. This is not an original thought of my own, I read it somewhere and cannot remember who to credit. But it has been on the backburner of my mind for some time. There's a problem with it.

Hypothetically, a rich person who can afford more children (afford better education, food, healthcare, access to information, etc) is more likely to survive in today's modern environment. The problem with this is that the rich are by no means the majority. Figure 2-20% in any given country. And that's kind of where I left it.

Dusted off, I present it here for discussion.

Permalink Reply by Jack Harkness on December 4, 2010 at 6:54am

While I may stray into the realms of science fiction in some of what I said several hours of research has convinced me that the heritability of IQ is from .4 upwards. One study refers to the age related IQ heritability which starts at .4 and increases to .8 in later life. Below is a quote from ”The General Intelligence Factor by Linda S. Gottfredson”.
”One is that the heritability of IQ rises with age--that is to say, the extent to which genetics accounts for differences in IQ among individuals increases as people get older. Studies comparing identical and fraternal twins, published in the past decade by a group led by Thomas J. Bouchard, Jr., of the University of Minnesota and other scholars, show that about 40 percent of IQ differences among preschoolers stems from genetic differences but that heritability rises to 60 percent by adolescence and to 80 percent by late adulthood. With age, differences among individuals in their developed intelligence come to mirror more closely their genetic differences. It appears that the effects of environment on intelligence fade rather than grow with time. In hindsight, perhaps this should have come as no surprise. Young children have the circumstances of their lives imposed on them by parents, schools and other agents of society, but as people get older they become more independent and tend to seek out the life niches that are most congenial to their genetic proclivities.”
Although there is some disagreement of the degree of genetic vs. Environmental influence in relation to IQ, the assertion that there is no correlation between smart parents and smart babies or dumb parents and dumb babies is incorrect.

Permalink Reply by Taran Rampersad on December 4, 2010 at 8:00am

Wow. I'd read the SciAm that the article was in (http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview&... ) and had forgotten that specific article (http://www.psych.utoronto.ca/users/reingold/courses/intelligence/ca... ) and its mention of heritability of intelligence. I was more interested in whether intelligence testing was to be considered worthwhile. Gottfredson wrote 'yes', but that same SciAm (1998) also had a few other articles that weren't complementary. Good special edition of SciAm; oddly enough I only recently got rid of my hard copy.

That said, the same author says in the very same article (the paragraph before your quote, strangely enough):

"...The existence of biological correlates of intelligence does not necessarily mean that intelligence is dictated by genes. Decades of genetics research have shown, however, that people are born with different hereditary potentials for intelligence and that these genetic endowments are responsible for much of the variation in mental ability among individuals..."

So it may be too much to say that intelligence is inheritable. The section you quote on heritability says that a person's intelligence is more affected by genetics as they grow older - not that it is determined by genetics. And those genetics have to do with the factors mentioned earlier:

"After taking into account gender and physical stature, brain size as determined by magnetic resonance imaging is moderately correlated with IQ (about 0.4 on a scale of 0 to 1). So is the speed of nerve conduction. The brains of bright people also use less energy during problem solving than do those of their less able peers. And various qualities of brain waves correlate strongly (about 0.5 to 0.7) with IQ: the brain waves of individuals with higher IQs, for example, respond more promptly and consistently to simple sensory stimuli such as audible clicks. These observations have led some investigators to posit that differences in g result from differences in the speed and efficiency of neural processing."

You'll note that these are physical attributes that are affected by genetics. A good metaphor would be 'bandwidth available' to be used for intelligence. It is not intelligence itself.

Thus, it would be more accurate to say that intelligence is still not determined by genetics, but that the potential for intelligence is inheritable.

And really... I wasn't there this morning when I first read what you wrote, but after re-reading that article, I realized what I missed 12 years ago.

An honest thanks! :-)

Permalink Reply by ROMAN ROMACH on December 4, 2010 at 9:10am

Thanks, Taran.
Jack, I wrote my piece late at night and was in a hurry.
My point is that it would be virtually impossible to take two, vast populations such as you mention and have them diverge in such profound ways. There is just too much genetic variability. You would need a small, carefully selected group for "breeding"... and the thought just creeps me out.

The suicide-bomber thing is purely cultural and religious, and not based on genetics. However, there is an interesting story which is loosely related to the subject: Why are French men shorter, on average, than other Europeans? Because Napoleon wanted only the tallest and biggest for his army and Imperial Guard.

I'll buy it!

Permalink Reply by Susan Stanko on December 4, 2010 at 10:02am

small, carefully selected group for "breeding"... and the thought just creeps me out.

Wouldn't work anyway. This has been tried in athletics and the results weren't anything less than you would expect.

Permalink Reply by ROMAN ROMACH on December 4, 2010 at 1:14pm

Another rare sighting of TESS (The Elusive Susan Stanko).

I don't know where people got the notion of producing a superior Homo sapiens? Superior for what? If I'm immune to all diseases but can't reproduce am I still superior? Wow, I was bred to compete in the Olympics - how cool is that!

And so it goes.

Permalink Reply by Jack Harkness on December 4, 2010 at 11:04am

Google the two articles below, especially the first one. It’s pretty heavy going but proves the almost direct correlation between processing speed and IQ.

The genetic correlation between intelligence and speed of information processing
Laura A. Baker, Phillip A. Vernon and Hsiu-Zu Ho

I.Q. - Genetics or Environment
Fabian Grasso
July 1, 2002

I have bred dogs for many years, though not so much now, and had 10 phenotypical traits to improve and maintain. They are working sled dogs and intelligence is one of the most important. This is why I have no doubt that intelligence is very heritable. Even a .4 or 40% heritable trait is significant. It means 40% is genetic and 60% is environmental. I agree it is an unlikely scenario for our species to split here on earth, (after all most men would choose a Paris Hilton type regardless of intelligence), but once on colonies off earth on say the asteroid Ceres, which would likely be a one way trip you would have your isolation of what will undoubtedly be a group of 130+ IQ people, (probably also with a much higher percentage of Atheists), who may not be able to return to earth for purely economic reasons. Ultimately the low gravity will prevent a physical return and evolution both physically and mentally will literally shape them. Sure not every child will be a genius, but the ones not able to take over the functions of their parents will have a definite lower breeding attractiveness to the opposite sex. The bell curve on Ceres will have shifted so far to the right that the non-genius will be an exception and the genius the norm!

Permalink Reply by Taran Rampersad on December 4, 2010 at 4:41pm

I know what you mean about dogs and intelligence - but the trouble is, how do you decide which dog is more intelligent (not 'trainable' than which? My brother-in-law was telling me how smart crows are, that somewhere they have them picking up loose change for nuts - I still have to look at that. That's adaptability, intelligence, whatever we want to call it.

While I see your point, I do believe that the potential for intelligence is heritable. I am uncertain that intelligence itself is heritable.

I wonder - with your experience... is the most intelligent dog the one who leads the pack?

I think it was the same SciAm mentioned above that also had the article regarding how people of above and below average intelligence have problems fitting into a society of average people.

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