Another odd observation, stevenlmeyer.

>>"modern medical care and sanitation practices,…" is, in evolutionary terms, a recent innovation. It has existed for a few hundred years at most. We now know that evolution works much faster than we thought. But it does not work THAT fast.<<

Our previous lack of understanding of the function of the appendix has nothing to do with evolution,

While in former times it had a valuable function to perform, it is no longer required to perform that function.

The chances are that the appendix, absent a reason for existence, will ultimately disappear from the human body.

In the meantime, it is still there, but for no apparent reason. That's why it took so long to work out what, in our less sanitary past, it did.

Evolution will continue to work at its own pace.

>>In the past few decades we have seen the rise of a Hindu nationalist party in India and the rapid spread of both Christianity and Islam in China.<<

The politicization of religion comes and goes. The "rise" of a Hindu nationalist party is akin to the militarization of Protestants and Catholics in Northern Ireland in the Sixties. Religious affiliations didn't actually change, they became more visible.

As for the "spread" of religion in China, that is to be expected - at least, in my understanding of why people are attracted to it. There will always be a percentage of the population who feel the need to believe in the existence of a God or Gods, and are consequently attracted to the formalization of such beliefs.

In a country where it has previously been dangerous to express such feelings, it is hardly a surprise that those emotions will now come to the surface.

Interestingly, it would appear that both mainstream religions are growing at the same pace. That indicates to me that it is not the external "message" that is creating the conversions; it's simply a matter of who gets to your vulnerability first, and fills you with the necessary amount of fear.

Steven,

An interesting thread.

Yes, MZ and DZ twin studies provide a good comparison to how to start to understand religiosity. Extracting factors from a principal components analysis would seem a good intermediate step. However, a structural equation model drawing upon nature and nurture components might prove more beneficial. Using path diagram software interrelationships should emerge. Of course, one would need to know a sufficient about potential genetic (or genetically-based neurological consequences) and social memes to build the model.

On the side of genetically-based neurological components, we have the Limbic System,which is part of the older brain and necessary for the survival instinct and; we have the Neo-cortex, which is responsible for higher thought. Religiosity built on spirituality could be a result of higher brain rationalising more primitive instincts: e.g., the rationalised notion (new/high brain) of an after-life as a response to survival instincts (old/low brain).

On the side of social memes, the basic model is that culture is a product of ecology (Triandis) and people are a product of their (cultural) environment (Skinner).

In sum, our genetically determined multilayered-brain might produce spirituality engrams along the lines of the above-stated. Also, we, live in environments which shapes spirituality predisposition to religiosity.

The above does not address brain chemistry. Susan Greenfield et al. note, many psycho-active drugs prevent the formation of undesirable neural nets.

Perhaps, our ancestors could have prevented the crimes of the religious zealots in history,given the right psychopharmacology. Else put, stopping the rationalising of the survival instinct, towards having the generalised spirituality coalescing to crystalise as a specific religiosity: e.g., belief in Zeus, Jesus or Alah as gods.

If the penchant towards religiosity is some sort of mental appendix (no longer needed), should we treat the condition? Or, would addressing/treating any society-wide pathology be unwise? Are delusions still delusions, when these staies are hard-wired into the brain and reinforced by society?

Appendum:

Maybe survival is hard-wired, spirituality firm-wired and religiosity soft-wired.

Bugsy,

If you are truly interested you should, at the very least, be reading New Scientist and Scientific American. American Scientist is also an excellent publication.

I built up a network during my years in and out of academe. So, yes, I do correspond frequently with scientists here and abroad.

If you have a specific question and you are able to frame it concisely and in such a way that you demonstrate your understanding of the topic you have a reasonable chance of getting a response. It's usually best to frame the question around a journal article your correspondent has published. A follow up phone call after an initial email can help.

However, if you want to be part of the global "scientific conversation" you have to participate in research. Why not do a research based Ph.D?

Of course if you know scientists who are involved in research you may be able to use them to start a network.

I keep my hand in by helping researchers with their statistics. (So, yes, I do know what it mean to say that genes are responsible for 40% of the variance of a trait :-D)

Incidentally, we now know that the simple Mendelian model of dominant and recessive genes does not adequately explain evolution. In the last decade or so we have learned that genes function in networks. We have also learned that parts of what was previously dismissed as "junk DNA" plays a vital role, perhaps THE vital role, in evolution. See:

Regulating Evolution; May 2008; Scientific American Magazine; by Sean B. Carroll, Benjamin Prud'homme and Nicolas Gompel; May 2008. This article is a MUST READ for anyone interested in evolution.

Hope that helps Bugsy.

Pericles,

Until recently we thought that we had kept our appendixes as useless appendages over "evolutionary time" – ie hundreds of generations AT LEAST. We now know that is not correct.

However since we are able to treat the difficulties caused by an appendix there will be no selective pressure to lose it.

My point exactly, stevenlmeyer.

>>Until recently we thought that we had kept our appendixes as useless appendages over "evolutionary time" – ie hundreds of generations AT LEAST. We now know that is not correct.<<

So it is in fact our knowledge of its historical function that has changed, not evolution.

Which continues to work at its own pace.

This I don't understand, though.

>>However since we are able to treat the difficulties caused by an appendix there will be no selective pressure to lose it.<<

How does the ability of our Health System to address appendicitis through surgery, reduce the likelihood that the appendix itself will eventually be "deselected" by evolution?

Or have I misunderstood i) you or ii) how natural selection operates?

Pericles

If having an appendix increased the likelihood that, say, you will die before having children, there would be selective pressure against an appendix. So the proportion of the population with appendixes could decline quite rapidly – say within a few hundred generation. More likely the nature of the organ itself would change within a few hundred generations.

However it seems that until recently having an appendix MAY have conferred a slight advantage – ie it would help you survive to have children. This is contrary to what had been thought. It may help explain why appendixes have survived in their current form over what appears to be tens of thousands of generation.

Then again it is possible that appendixes only became a liability with the advent of modern diet.

Right now having an appendix causes neither a significant advantage nor a disadvantage. Over evolutionary time it will probably wither but this could take many thousands, perhaps tens of thousands, of generations.

I am not sure why you are so focussed on this. I included the link to the article merely because I thought it was an interesting tidbit.

A much more interesting discussion is when and how we became NAKED primates. This is still very much an open question. Speculations abound and some have gained popular currency but no one is certain.