Misconceptions about Evolution: A Defense of Terence McKenna’s “Stoned Ape Theory”

Recently I was reading a “Reality Sandwich” blog post written by a Brian Akers from 2011 titled: “Concerning Terence McKenna’s “Stoned Apes” ” which attempted to de-bunk Terence McKenna’s “Stoned Ape Theory”.  I am a proponent of at least some concepts that lie within this theory, specifically that the ingestion of psilocybin cubensis, i.e., “Magic mushrooms” (as well as other psychedelics) played a role in altering the course of early human and/or pre-human (i.e. homo-erectus) evolution.  Needless to say I was interested in hearing what Akers had to say, as he was critiquing one of TM’s best works titled: “Food of the Gods”, which discusses this theory in detail.  Akers went to some length to explain the flaws in TM’s theory, based on Akers’ idea of how evolution “really works”, and he also questioned the credibility of some of TM’s claims based on a lack of citing enough references to support his position, and also questioned the credibility of some references he did have.  I agreed with some of the points that Akers made but I took issue with some of the reasoning that Akers used in refuting the theory, specifically regarding the mechanisms behind sexual selection and evolution in general.  Here is the first excerpt I disagreed with:

Even if psilocybin did enhance visual acuity however, or make you more “horny,” such effects could not play a role in selective processes along lines TM argued.  Why?  Beyond false facts lies a general problem of fallacious reasoning from misconceptions about evolutionary processes.  Such misunderstanding is not uncommon, TM and his audience hold no monopoly on it.

In this light, suppose this attention-grabbing ‘horny’ claim were true. “Horniness” neither produces children, nor success in competition for mates.  Just ask males of a sexually dimorphic species like lions, who must fight each other tooth fang and claw in a run-off that ends in only one having breeding privileges, the rest left to console each other, out of luck. They can be as “horny” as they want, it makes no difference whatsoever for chances of their genes passing into the next generation.  The predicted winner is the bigger, more powerful male, with thick mane — not “horniest” (that’s irrelevant).  For possible adaptive advantage, ‘visual acuity’ enhancement seems less nonsensical, by comparison.

It appears that Akers has implied at least three things here: 1) the mating and sexual selection characteristics of a sexually dimorphic species such as lions matches (or closely resembles) that of humans, 2) which animal is the “horninest” is irrelevant to sexual selection (changes in the gene pool), and 3) physical competition (i.e. fighting) is the dominant, if not the only, mechanism for sexual selection.

Since when do all sexually dimorphic species share the same mate selection criteria and mechanisms? I can’t remember fighting another male such that I could have sexual intercourse with a potential mate. All of my relationships (especially those that led to sexual intercourse) were built upon a foundation of dialogue, shared experiences, and some level of mental and physical attraction. Has Akers never “won” over a mate by utilizing some degree of either good looks, charm, wit, and/or other intellectual prowess? If he has only physically fought other males in order to have sexual intercourse with a potential mate, then I don’t think he has had an experience like most, if not all others that are taking the time to read my (as well as Akers’) post. Akers also needs to realize that there are different degrees of dimorphism which are correlated with completely different types of sexual behavior.

If Akers really thinks that “horniness” is irrelevant to evolutionary changes in the gene pool, then I’d like him to support this position with sociological data that demonstrates that humans with a high libido (and little or no access to birth control) have no correlation with higher pregnancy rates. I don’t think the data is there to support this, especially given the fact that, as I mentioned in the previous paragraph, humans often are not physically fighting over mates. If the relationship is mutual and/or an open relationship with multiple sexual partners, then libido will certainly be a large factor when predicting which genes are most likely to pass on to the next generation. “Horniness” is far from irrelevant.  One could go so far as to argue that in the case of the male lions, having a high libido may actually increase their physical aggressiveness in the fight to come.  However it’s not necessary to limit sexual selection mechanisms to that of physical competition.

Sperm Competition

Akers has implied that physical competition is the dominant, if not the only mechanism affecting the fate of the gene pool. Another huge mechanism that Akers failed to consider for natural selection is that of sperm competition.

If we want to hypothesize what our early human or pre-human (i.e. homo-erectus) ancestors may have been like in terms of their sexual selection mechanisms and sexual behavior, it would be reasonable to look at the behavior and anatomical differences of other primates living among us now. Bonobos for instance have a degree of sexual dimorphism that is similar to that of humans (e.g. a level around 15-25 percent), whereas gorillas and orangutans (which tend to fight over mates and have harems dominated by an alpha male) have a much larger degree of this dimorphism (e.g. a level which is around 100 percent). Bonobos are incredibly promiscuous where the females often copulate with a large number of males, sometimes as often as 50 times a day, and the evolutionary trade-off that primatologists propose is that this sexual behavior increases the level of social cohesion between the males as well as the females. Even the females are often seen rubbing their own genitalia against one another to increase this cohesion.  It’s easy enough to see that if the males are not fighting in a pecking order or battling over “who gets the booty”, then they are able to form strong symbiotic relationships and bonds which foster more cooperation thus benefiting the group overall.  In effect, the sperm competition between males is nature’s way of eliminating the external physical battle, and moving it to a scale that no longer risks the elimination of the gene’s vehicle (i.e. the battling males).

The loud vocalization of female bonobos (and human females) during orgasm suggests an audible invitation for other males to join in on the fun. There doesn’t appear to be any other advantage, as making noise in the wild often draws attention to predators and thus the benefits of this “female call” may compensate for this predatory vulnerability.  Also, the fact that it takes women as well as female bonobos a significantly longer time to orgasm when compared to the males of the same species also supports the idea that we are perfect for promiscuous sexual relationships with multiple males copulating with each female. This is not a type of behavior that we see in polygynous or monogamous species that simply fight over mates, and thus this behavior is again seen as another example of sperm competition in action.

The sperm count of humans and bonobos are also much larger than that of orangutans and gorillas, which is not necessary if we evolved to fight and win over a mate with which we could copulate with as often as needed to impregnate. Human males also have a penis with unique physical characteristics that support sperm competition. For example, the glans (or head) of the penis is shaped like a plunger which sexual and evolutionary biologists believe is perfect for creating a vacuum in the vagina in order to pull out previously deposited seminal fluid and sperm such that the male is able to impregnate the female with his own deposit. This theory has actually been validated in a laboratory setting with artificial molds of a penis, vagina, and corn-starch based seminal fluid (some tests showed as much as 90% of seminal fluid was displaced after a single thrust). The relatively large number of thrusts during human sexual intercourse as well as the duration when compared to many other primates amplifies this seminal displacement effect.

The fact that human males have their sperm production sites and testicles located in an external, physically vulnerable location is correlated with an increased number of sperm and is correlated with primates that are promiscuous. There is even a form of rapid-reaction DNA present in humans which mediates testicular tissue development allowing humans to rapidly change their testicle size and sperm production capabilities in evolutionary time scales often thought to be too short (thousands of years). This rapid-reaction DNA is not present in monogamous or polygynous primates for obvious reasons.

Let’s not forget about some characteristics of the human female’s sexual anatomy. The complexity of the human cervix which filters sperm by creating countless hurdles suggests sperm competition and selection is at play. Women have anti-sperm leucocytes located in their reproductive tract who’s sole purpose is to kill sperm, such that only the strongest (or chemically compatible) sperm will survive to the end in order to fertilize the egg. It seems that in this case, whether or not a male is stronger or able to fight over a mate is less relevant than the compatibility between the male’s sperm and the woman’s egg. In this case, the woman is actually choosing the sperm on several levels (physical filtration, chemical filtration, and even the sporadic occurrence of an egg “enveloping” a reluctant sperm).

So clearly, by looking at the facts, sperm competition is much more likely as the dominant mechanism behind evolutionary changes to the human gene pool. It is also likely that this was the case with our closest ancestor (i.e. homo-erectus).  Many similarities can be seen in bonobos which live among us today and share so many other characteristics of human beings.  It’s more appropriate to hypothesize our immediate ancestors as being similar to these primates rather than to those that are similar to the dimorphic lions (e.g. gorillas) which Akers assumed.

The Baldwin Effect

Next, Akers makes some more narrow-minded claims about how natural selection operates in the following excerpt:

But it’s nonsense still, because of how evolution actually occurs. In favoring adaptive traits, it’s the genome selection operates on, across generations in a reproducing population. If an individual carrying whatever gene reproduces, he or she serves as a means for its transmission to the next generation. Biological evolution = change, to any degree, from one generation to the next, in proportions of GENES in a population. To my knowledge TM never proposed a gene for “eat psilocybin” in the hominids who in his fanciful scenario ate mushrooms, vs. those who did not. Genes may render some particular food(s) indigestible, but no gene governs that we eat mushrooms or don’t.  Without a gene that could be selected if adaptive, there’s nothing to inherit from eating fungi; thus no toehold for selection, regardless how many offspring.

Akers has completely failed to consider the Baldwin Effect on evolution. If there are any benefits provided by eating these psilocybin-containing mushrooms including but not limited to: increased visual acuity, increased libido, increased social cohesiveness due to ego-boundary dissolution, or otherwise, then by learning the behavior of eating those mushrooms, and having that behavior imitated by other individuals in the population — one can change the gene pool. If a species gains any advantage at all by eating these mushrooms, and these advantages are spread through the population by those that imitate the behavior, then only those that have the ability to imitate this behavior will gain the advantage. If this is the case, then those that have this ability will be more likely to reproduce if said advantages exist. The same situation applies if a species learns how to evade a new predator which it has not evolved to avoid with instinct alone. If certain other individuals in the population learn that new advantageous behavior, eventually the gene pool will start to show a greater proportion of individuals that imitate this behavior. Thus the ease of learning a particular behavior affects evolution of the species — even if the ability to learn this new behavior is mediated by genes (which mediates brain wiring, its level of plasticity, etc.). Learning is just another dimension of ontogenic evolution that affects the gene pool based on the success of the meme, as long as the behavior learned provides some advantage. So if eating psilocybin cubensis has any positive effects whether it’s stress relief, ego-boundary dissolution promoting social cohesiveness, increased visual acuity (or other visual changes), synesthesia, increased hearing acuity, linguistic thinking (leading to better organization of thoughts as well as more complex levels of thought), beneficial altered perceptions of space and time, increased libido, etc., then those organisms that pick up the behavior of eating that food preferentially over other foods may be more likely to survive longer and/or reproduce.

I do appreciate Akers’ research into the credibility of some of TM’s claims as there were certainly a few instances of either misinformation or poorly formulated claims within the theory, but his theory, at least in part, still stands. There may be flaws in his theory, but that doesn’t mean that we can dismiss the theory in it’s entirety, that is, that mushrooms played a role in human evolution. The fact that humans eat mushrooms and they are/were present in Africa where our early hominid ancestors originated implies that it is certainly possible. The fact that there are some attributes of a psilocybin cubensis trip (under certain dosages) which may be advantageous to a species implies that it is certainly capable of altering the gene pool through the Baldwin effect, and thus it is quite plausible that it may have altered the course of human evolution for these aforementioned reasons.