Apologies, I'm still stuck typing with one hand so my response won't be as robust as I might like.

The fool's errand you mention is commonly referred to (often pejoratively) as "biological determinism". We are in agreement on the emptiness of that line of inquiry.

What's interesting to me is that various cultural and environmental inputs are not absorbed equally by human brains. You mentioned bigotry, I mentioned in-group/out-group bias; these are fundamentally similar (as are ethnocentricity and xenophobia). It turns out that humans are more susceptible to absorbing, developing, and maintaining this sort of bias than say… a bias toward the typeface Helvetica. Evolutionarily speaking, this served as a heuristic that conferred a survival advantage. It's safer to avoid strangers in an unknown world (especially a pre-language world). This type of behavioral shortcut is described by "error management theory", which I'll write more about later.

Why I find this important to explore and understand is that, in the modern world, one's views on Helvetica might be more important from a rational standpoint.

It also turns out that fear works in a non-rational way in the human brain. We generally develop fears of snakes and spiders easily, but rarely develop fears of driving 80mph on the freeway. The latter is much more likely to kill us today, but spiders and snakes provided selection pressure over evolutionary time. People with a fear of spiders and snakes tended to survive longer. Hence the cliche "a healthy fear".

Because humans have a bigotry bias and a strong visual bias, we could predict (retrodiction may be more accurate) that a bigotry bias delimited by visual cues would be particularly likely in our species. Understanding the alignment of multiple non-rational biases is an important bit of information if we hope to survive as a species. I'd go further and say that rather than culture creating, then imparting, these biases, it has subsumed the inherent human impulses and reflects them back on us in a way that amplifies them.

Question #3 in my (unfinished) evolutionary psychology FAQ was an early attempt to answer this type of question more generally.

You might also glance at Blank Slate, SSSM, and Biological Determinism on my evolutionary psychology definitions page.

Ah the 'why'. I would lean more towards modern (last 2-3000 yrs) social/religious constraints but I could be way off. I would think someone has done a study (or maybe not) on 'primitive' tribes, the few that remain, and their reaction or non reaction to porn. If the society is open about sex, nudity, etc.. is porn that influential?

I'll have to wait for your next article on the subject. Thanks for all the great info here btw…you helped start me on the paleo diet…so far so good.

Again, we don't disagree. The only difference is that you're talking about the how of evolution and I'm thinking about the why. That is, why did the brain get "wired up" in such a way that porn works. My thinking was that it's an odd abstraction of visual bias and cognition/imagination.

To make that connection, it's necessary to describe the connection between our visual sense and the fitness indicators we've developed because of it that are used in sexual selection. I'll cover that in upcoming post(s) I alluded to involving beauty and attraction.

"…why would the human mind be wired up to trigger a dopamine release at the sight of any 2D image?"

My guess would be that due to human brain evolution from reptilian brain (archicortex?) to mammalian (paleocortex) to human (neocortex) brain…. the visual cortex enlarged through evolution (includes Primary (V1) plus extrastriate regions through the dorsal and ventral pathways). Basically the visual information is passed on to most parts of the brain for information dissemination. We evolved to become a visual species. It makes sense that visual stimulation is more powerful…at least to my simple brain. Of course it is interesting that we pursue a complex type of stimulation to activate a rather primitive part of the brain. Our other sensory areas have declined in size such as olfactory which is in the more primitive section at the base.

Interesting. This is the first I've heard about it, but it looks to be right up my alley (aside from the fact that I don't have kids). It gets super-high Amazon ratings from a lot of people. Anyway, I've linked it up in your comment. Thanks!

I don't understand the concept of "too deep". 🙂 I want to hit the bedrock foundation and the very very bottom.

We're not in disagreement on the proximate mechanism of dopamine reactivity. My question to you would be, why would the human mind be wired up to trigger a dopamine release at the sight of any 2D image?

This relates to your point about regional race biases being a shortcut to identifying potential threats (a point with which I also agree)… Error Management Theory: A New Perspective on Biases

Racism may also be rather simplistic, rooted perhaps in a primal segregation for climatic survival purposes. Skin pigment, muscle/fat ratio and density, even eyelid shape and body hair all are due to environmental factors our ancestors evolved in order to survive their particular climates. Thus racism could be a deep primal bias that someone of a different race couldn't survive (be successful provider/produce viable offspring) in ones 'home' region. This of course doesn't matter in present time since climate can be controlled (indoors), clothing evolution and new tools can make anyone successful in most climate regions. But is it reasonable to expect that primal bias to vanish? Should we be able to 'mentally evolve' past that? I would like to think so, but reality proves different.