The Ghost In The Pepper

Ghost PepperJust the other day, I had the rare pleasure of eating chicken curry fortified with a healthy dose of “Nai Mirris” (cobra chili in Sinhalese, or better known internationally as the Indian Ghost Pepper). Hot chicken curry is a local delicacy, although of late the dose of “heat” in curry seems to be waning, due to 21st century gastronomic trending that delivers mild, watery food that “damages the system less” (sorry for the gripe). Anyways, after enjoying a lovely meal of hot meat and rice, I got myself thinking about the origin of the “heat” in peppers, and how they might have evolved this adaptation (if at all “heat” is one).

A quick side note; seemingly, the pleasure of eating very hot curry is an acquired taste. This idea is reinforced by the observation that little children are most vehemently repulsed by chili. One would suppose that it would take years of gradual conditioning of one’s taste buds to enjoy the “tasty” side of the chilies’ flavor, whilst ignoring the fiery mucosal reaction.

Back to my philosophical musing. Let us assume for a moment that the “heat” in peppers is an evolved defense mechanism of the seedpod to favor certain dispersal mechanisms over others. If this is true, have you ever wondered whether the existence of “hot” pepper bearing plants in the wild, might predicate the existence of qualia or subjective (taste) experiences in certain animals that the pepper has evolved to repulse?

Here is how I’d argue the case. The pepper’s heat gets selected in Darwinian terms because it repulses certain higher animals (e.g. mammals like cows or goats) that have a quail about capsaicin, the active “hot” ingredient. Less of the seeds get destroyed or deposited in nearby soil after digestion by mammals, and more are distributed to far out places via birds, who apparently don’t seem to have a quail or mucosal reaction for capsaicin. Wider dispersal increases the durability of the pepper species, and hence any mutations that increase their seedpod’s capsaicin content get adapted in a Darwinian sense.

So, where’s the evidence to confirm the existence of qualia or a subjective experience in the mammals that hangout near pepper trees? After all, couldn’t the aversion to the early peppers be an unconscious defense reaction to save the mammal from bodily damage caused by the capsaicin? This assertion might be false. The damage to the mucosa that is caused by the dilute capsaicin dose found in wild peppers is localized, temporary and nowhere near life-threatening proportions at first bite. So how could a random, unconscious aversion to pepper in a given mammal get selected down its evolutionary tree?

Let us juxtapose a case from the evolution of danger awareness. Consider the aversion to poisonous snakes that many animals display (unconscious or otherwise). In this case, contact with a poisonous snake clearly increases the likelihood of death. This is of Darwinian consequence. Any mutation that causes unconscious aversion to snakes will be selected in a Darwinian sense. There is no need for the aversion to have been consciously thought-out or “felt” (i.e. generate a quail). In the case of capsaicin, there was never a danger of death, especially in the early peppers. So any mild aversion to pepper in the genes of a mammal will probably dilute or die out. It cannot be the start of a typical evolutionary “arms race”.

My conjecture is that way back in the evolution of pepper plants, there would have arisen a mutation that generated capsaicin, which caused unpleasant or “hot” qualia in mammals, from day #1 of the mutation. The original aversion might have been a mere spandrel. This aversion caused the corresponding pepper strain to gain an immediate survival advantage, due to the opening up of alternate dispersal vectors such as birds, who dispersed the ripe seeds far and wide. The fiery peppers spread – the hotter the better. In other words, the original mutation caused a behavioral change in other species that predated on the pepper, giving the pepper an immediate survival advantage.

It is noteworthy that a conventional evolutionary “arms race” requires death or sexual selection in the equation. I cannot see he role of either death or sexual selection in the case of the evolution of the Ghost Pepper. Instead, there seems to be a dependency on revulsion due to distaste – as a result of subjective brain-states in the animals concerned.

The above hypothesis is based on many fundamental assumptions about the nuances of animal evolution, such as the reason why animals react to pin-pricks is because, way back in their evolutionary past, the damage to bodily integrity caused death in some creatures, whilst others who had the mutation of sudden movement survived (in an oversimplified sense). I cannot fathom a similar “ancestral” argument in favor of the revulsion for hot peppers; e.g. the ancestors of mammals died consuming the capsaicin in the ancestors of peppers, thus both propagating the revulsion in mammals and benefiting the pepper – sounds rather unlikely.

I concede I could be clean wrong about my notion of qualia bootstrapping the evolution of peppers; so I’d greatly appreciate critical comment, particularly by those who have studied the heat in peppers from an evolutionary biological standpoint.

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