How well are we currently adapted to our environment?
The human evolutionary environment underwent a drastic change when, with the Neolithic Revolution we adopted agriculture and began to live in settled communities. Put in the simplest terms – at this point in history our environment of evolutionary adaptiveness changed from from ‘wild’ to ‘man-made’, from ‘natural’ to ‘artificial’, from ‘nature’ to ‘culture’. From living in temporary dwellings, gathering plants and hunting animals we began eating domesticated plants and animals and living in larger more population-dense and built environments: it was the first major step on the path to modern city living. Some, like Jared Diamond, believe that it was the reason for a profound schism between humanity and nature. “With agriculture came the gross social and sexual inequality, the disease and despotism that are the curse of our existence”.[Diamond, J. 1987. The Worst Mistake in the History of the Human Race. Discover, May edition.] Others see the matter differently. Do we have pre-agrarian bodies and minds – stone age genes in a space-age environment? Does it matter that when once we were with our animal relatives in the wild and now we live in buildings and cars with artificial climates and we sit in front of computers and assorted electronic gadgetry for hourse every day? For an account of the discussion see see Neolithic Revolution. Writers also make the general points that with the Neolithic Revolution our basic attitude to nature changed from one of ‘respect’ to one of ‘control’. Associated with this is an increasing detachment. Once part of nature we were now separate from it, a view reinforced by the advent of Christianity which reinforced the primacy of humanity in the scheme of things and removed spirituality from nature and placing it in an afterlife. Here we can consider some of the pros and cons of our evolutionary psychology.
Are we now misfits – have we created an evolutionary mismatch?
How well do we fit into our present-day environment of evolutionary adaptedness? What are the selection pressures operating in modern industrial societies and where are they taking our future evolution? They certainly do appear very different from those operating in the Palaeolithic?
Though we cannot assume that we were once perfectly adapted and in sync with our ancestral environment, or that we are no longer evolving, evolving slowly maybe, but not stuck and frozen in the past, there is substantial evidence to suggest that evolution has not prepared us for the 21st century and that culture must address deficiencies that are our evolutionary legacy. Here is some of the downside in our biology:
1.Our craving for salt, sugar and fats which probably relate to our evolutionarty history such as the need for the quick energy present in the sugar of scarce fruits – leading today to obesity, hypertension, heart disease and other physical ailments.
2. An absorption with passive TV viewing because we have are hard-wired to respond to exaggerated social cues like laughter, smiling faces, and attention-grabbing action.
3. Our enormous emotional investment in the inconsequential outcomes of sporting activity
4. Our ancestral fear of dangerous natural objects like snakes and spiders has not been matched by a similar fear of much more dangerous man-made objects like guns and cars? Evolutionary psychology has a major task in taking such theories from the realms of ‘plausible’ to ‘likely’ or preferably ‘scientifically proven’. Cases like this though do illustrate what novelists and playwrights have been telling us for a long time: that humans-evolution is flawed. The array of emotions and drives we have inherited from the past – love, hate, jealousy, anger, fear, and sexual attraction can go awry as it does with crime, they have trade-offs.
5. The psychological drive that stimulates us to reproduce and pass on our genes is the same drive that can lead to rape, sexual harrassment and so on.
6. Much of morality and the law is concerned with the repression of natural desires and emotions.
7. Our demand for meat has, through agriculture and pastoralism, placed an enormous burden on the natural environment.
Can we assume that because our environment of evolutionary adaptiveness has changed so drastically that we are therefore now poorly adapted – we have modern diseases like diabetes, hypertension, and rheumatoid arthritis. Modern medicine has now vastly reduced the high mortality rates that once ‘weeded out’ mal-adapted individuals. Everyone from the mild asthmatic to people with major genetic disorders now live to pass on their genes, if they wish to do so as a result of improved medicine, food production, and sanitation. In Shakespeare’s time only about 35% of babies reached 21; in Darwin’s day it was 50%; nowadays it is over 90%. Indeed it appears inevitable that through this mechanism we are progressively introducing genetic ‘weakness’ into the human race.
Back to the Palaeolithic?
Should be living more like Palaeolithic humans with more ‘natural’ lifestyles and diets that contain more fruit, nuts and cereal and less fats, salt and processed food? Should we be getting back to nature, re-connecting with the natural world and paying more attention to primal needs?
In making such judgments we are not assuming that life ‘then’ was better than ‘now’ or that the way it was then was the way it was ‘meant to be’ or that we were at some time perfectly adapted to our environment, or that there was a period in our cave-living days of blissful harmony when, like noble savages, we lived at peace with our environment and fellow humans. In all probability Palaeolithic humans, like many of us, looked to the past in the belief that this was a better time. Evolution has surely never been ‘finished’ always a constant tussle of trade-offs.
But if we were hunter-gatherers for 99% of our history as Homo sapiens, isn’t this more likely to be a lifestyle to which our bodies and brains are better (but not perfectly) adapted?
There are several ironies here.
Firstly, if this is indeed the case then it would seem that through the effectiveness of our short-term medical expertise that we are increasing the likelihood of our longer-term demise, this is akin to the way that inoculating domestic animals to resist organisms that would normally affect them perpetuates the rist of the spread of those organisms.
Secondly, much of modern medicine is combating infections due to organisms that are themselves evolving and in doing so, overcoming our medical remedies (vaccines, antibiotics and the like) – this is in a sense an arms race with an uncertain outcome: there would always seem to be the chance of a disease arising to which we have no remedy – in which case raw natural selection will return with avengeance.
Apart from this particular scenario, humanity has now entered a new phase of evolution in which through medical technology and genetic engineering we are now writing our own evolutionary future. We are close to the point where we can manipulate our genetic makeup in whatever way we please. Designer children are just a first step along this road.
We are accustomed to the religious idea of life being sacred and sacrosanct. We also at present accept without protest our genetic fate. As genetic knowledge increases it seems likely that acceptance of the ‘genetic lottery’ will diminish.
Tinkering with the DNA at the core of all life is a matter for bioethicists, biotechnology companies and likely to become increasingly a matter of public engagement.
See BBC Television Program Are we still evolving? [reproductive success not mortality]
How fast are we evolving?
Gene frequencies indicate that human evolution has never ben more rapid than in the last 20,000 years, presumably as a result in the huge changes in lifestyles, adjustment to agriculture, new foods, cities and communal disease.
A key example is European lactose-tolerance absent about 20,000 years ago, fairly common at the time of the Romans and now present in over 90% of people.