The Meaning of Life and Other Vegetables

Hello everyone.

I (very naively) set out to obtain a good working understanding of Dopamine, addiction and related topics. With the amount of buzz, hype and chatter I felt around, I had the impression that a lot of related scientific knowledge was gathered in the last, say, 30-40 years; that a significant, solid consensus exists in this field; that the base terms, definitions and concepts have been laid out and clarified thoroughly; and that the field has already rightfully moved into the phase of elaboration as popular-science for the masses (implying an existing, solid formal-science foundation).

The result of that quest? A big confusion.

My impression was wrong.

The apparent reality: Terminology is vague and elusive. I bumped into a lot of loose “associated with” and “evolved essentially for”, and much less precise description of mechanisms or even high-level rationales. I came across a surprisingly low occurrence of unambiguous, scientific-style hypotheses. Consensus covers only the very crude, general ideas, and sources (including apparently highly qualified ones) often contradict each other, when a dive at any depth is attempted. Outdated / poorly conceived ideas, already demonstrated to be likely wrong up to a decade ago (“Dopamine is released when we feel pleasure”), are still perpetuated as if they were mainstream truths, including in, for example, professional instructional videos from esteemed institutions.

It’s not all dark, though. I came across a few, highly qualified scientists (think Oxford neuroscience professor level), who openly, though in a low-key tone, downright admit “The <x, related> mechanism in the brain is currently poorly understood” and “Our current thinking about <y> is based on animal research; we don’t really know about humans.” I highly respect this kind of honesty, yet the net effect is mostly adding to the sense of lacking knowledge.

So, I still haven’t found what I’m looking for (thank you U2, haha), and I’m unable to share any concise, second-hand insights; but I feel the topic is still worth a discussion here. I’d like to start today but I feel it’s a heavy / challenging topic, so I’ll hit it off and maybe revisit it later.

The sub-topic I’d like to discuss today is the internal workings of feeling pleasure. Almost any available discussion of Dopamine, its roles and its action mechanisms starts with highlighting Reward. But reward is not the same as pleasure. Most sources I came across seem to agree that a reward is a beneficial / wanted outcome, which might result from a possible, specific choice or action. At face value, Pleasure can be a Reward. Furthermore, the way we have evolved – I speculate – all types of rewards translate to pleasure it you dig a little. Hence, it seems that a clear concept of what pleasure essentially is, and how it works (preferably, eventually in precise formal-science terms) will be very useful in elaborating about Reward, Dopamine, addictions and related topics.

In trying to conceptualize pleasure, I chose to look at is from an evolutionary perspective. It’s not obviously related here, but I can’t help thinking about Prof. Hoffman’s take about subjective experiences, pleasure included (according to hm). As you might remember, he challenges the idea that consciousness (and conscious experiences) arises from non-conscious matter, which is by far the prevailing notion, and he repeatedly highlights that despite huge budgets being spent and the most clever people researching those topics over the last 50 years, not much progress has been made in explaining how conscious experiences arise from non-conscious matter. “How does the experience of the taste of chocolate happen? Where does it come from?”, in his words (it’s not that simplistic; I’ve written about his theory quite a lot in this blog and you are very welcome to read more). With pleasure apparently being a similar subjective experience, those points seem relevant here, and I feel that the confusion I currently feel around the topics I mentioned above sits very well with Hoffman’s attitude. Coming back to my choice to examine the phenomenon of pleasure from an evolutionary perspective, I find it a nice coincidence(?) that Hoffman’s thinking is strongly rooted in his earlier scientific interest in the (biological, Darwinian) evolution of visual perception.

So, what is Pleasure?

Animals are phenotypes (manifestations) of their DNA. Where a specific DNA is given, it manifests as a creature that would act in specific ways (driven by that DNA’s code). If those specific ways lead to survival/preservation (first) and procreation (second), that DNA will remain observable. Otherwise, it will perish and lose its observability. It’s not a matter of “better” or “worse”, “fit for purpose” or the likes. It’s simply an essentially-blind, cause-and-effect outcome.

Now let’s look at eating a benign, ripe banana, for example.

The animal approaches the banana and ingests it. Let’s assume that that specific animal derives objective biological benefit from digesting that banana, for example, it gains sugar which it needs for function, survival and maybe even procreation. While the animal is ingesting and digesting the banana, certain things happen inside its body, and some of them can theoretically be detected. Suppose that a specific set of chemical conditions (for example) takes place while the banana is being digested in the animal’s intestine. Let’s refer to that set as the “banana eating fingerprint”. It’s already established that eating that banana is beneficial to the animal, so that fingerprint can represent a desired state. If that animal pursued that fingerprint, it would likely be better off overall.

Now imagine two DNA versions of that animal, and their phenotypes / manifestations. One version can somehow memorise that beneficial banana fingerprint, and reference it in the future:
1. Ingest something (potential banana?)
2. Compare with stored fingerprint
3. Match? Continue, maybe ingest more
4. Not a match? Spit out, move away from source

The other DNA version / phenotype doesn’t. Either it doesn’t memorise, or it won’t act on the memory in an affective way, or otherwise. The important point is that one version can utilize that fingerprint reference to its benefit, and the other one can’t. On average, the former has an evolutionary advantage – it’s a tiny bit more likely to survive and procreate, to maintain observability. That DNA is more likely to “continue to the next round”, while the other one is more likely to become an evolutionary dead end.

Now consider a different aspect of the animal’s survival and procreation. For example, the set of touch/pressure sensations that it would feel during a mating act that is likely to end in conception. That’s another fingerprint that might be useful in identifying and pursuing an activity which, on average, contributes to maintaining a specific DNA version.

The number and variety of such beneficial fingerprints for a creature as complex as an ape (or a dog, or a mouse, for that matter) would be enormous. Suppose that a given DNA (or its phenotype) was to account for such an enormous “library” in a way that each one of them provided a clear motivation to pursue the related, beneficial activity – that might yield a very complex, perhaps less efficient, system.

Add onto that the complication of volition: Hard-coding a large library of trigger-and-reaction items is perhaps not a task too big for an ape DNA, but it seems to me that once conscious choice enters the picture it would become quite formidable. Managing a myriad of different kinds of stimuli, weighing them against background conditions and perhaps against each other, and consistently coming up with an optimal decision, in a timely manner, seems computation-demanding.

What if the coded benefit could be standardized? What if there was a universal switching centre that took the various fingerprints as input, and translated them all into a single type of signal? In that case the magnitude of that signal would be a simplified, efficient means of comparing the relative value of any given fingerprint (standing in for an actual benefit, like eating a banana).

I speculate that this is what pleasure is. Scientific research papers call that “universal switch” Hedonic Hot Spots, and locate them in this or that region of the human brain. A simplistic way to envision it would be a nerve cluster that would “light up” to signify that “something very good is going on”, that evolutionary benefit is being gained.

One scientific expression commonly used in this context is “endorphins are released”, but what does it actually mean? In the context of pleasure, endorphins act as neurotransmitters. Unlike situations where endorphins act as hormones, where they are released (for example, into the blood stream), neurotransmitters are hardly ever “released”. For the most part, neurotransmitters act in the very tiny gaps called synapses, between 2 neighbouring (and communicating) neurons. I’m not a neuroscientist, but the (simplified?) way I envision that specific cascade would be:

1. An encoded message about a beneficial fingerprint would arrive at the Hedonic Hot Spot via a nerve.
2. That nerve’s axon would “release” an endorphin.
3. That endorphin would land in a receptor on a neuron that is an integral part of the Hedonic centre nerve cluster.
4. Given enough such triggers (or proportional with their number), that nerve cluster would “light up” = the experience of pleasure.

Why does it “feel good”?

No particular reason. There is nothing absolutely “pleasurable” in that cluster lighting up. It’s merely shorthand that our body uses for denoting something which kept our specific DNA in circulation. DNA versions that didn’t do that are no longer around. They failed to signify the benefit in that manner, so their owners (actually, their phenotypes) didn’t pursue those benefits as efficiently and as ruthlessly as they could, and so they ended up inferior in terms of preservation and procreation.

One last comment: In such settings, it might still be useful for the creature to distinguish different kinds of benefits, hence “different kinds” of pleasure. The taste of a cube of chocolate and the sensation of orgasm are both pleasurable, yet they feel different and we can tell them apart regardless of magnitude. One might argue that they are “felt at different sites”, but technically they both occur in the brain (the location is merely referred). I speculate that in essence those two seemingly different signals are the same – they light up the Hedonic Hot Spot, and in doing that they serve as motivators to pursue actions likely to lead to gaining benefits they code for (that’s where Dopamine enters the picture – more on that later, maybe). I also speculate that “feeling different kinds of pleasure” is again a shorthand our brains use, a stand-in for the combination of “pure pleasure sensation” (in the Hedonic Hot Spot) and additional specific sensory data related to the specific experience. Let that be my modest contribution to the effort of framing clear and precise scientific hypotheses (which could then be tested, hopefully)…

That’s all for today. Peace to all.

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Did you know…? There are more posts in this blog than are presented to you right now. It’s an attribute of the template which I can’t change.
How to see all of them?
Click on the header – the bold “The Meaning of Life and Other Vegetables” at the top. You’ll get a list (which is not complete either), with a button at the bottom to access the next list, and so on. Those go all the way back to my first post in this blog.
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