Snailfinity Gauntlet

There’s much debate about the emergence of human intelligence. While one could dismiss the gift as a simple evolutionary tool, akin to how fish have gills and birds have wings, our gift is different. Not only has it been a tool for survival, but also one that has given our otherwise weak species dominance over the planet. It’d be like if one day a snail pieced together the Infinity Gauntlet, and no one even questions how the snail could have done it.

Intelligence Is More Than an Evolutionary Race

Add in a cup of Darwinism, a teaspoon of Hollywood Sci-Fi, and maybe a sprinkle of Pokemon for taste, and you get a very slanted view of the influence of evolution on intelligence. Evolution is a game of chance, for the purpose of survival, but is often portrayed similarly to watching a baby turn into a smart adult. Often, though, evolution doesn’t require you to become smarter, just more adapted. Intelligence might be mixed into the equation, but it is not a necessity.

Evolution doesn’t necessarily make you smarter.

Take, for example, the rat. We can all agree that rats are an inferior to humans when it comes to intelligence (at least as we understand it). Around 80 million years ago, the lineage between humans and rats split from a common ancestor. Scientists estimate that, since that split, rats have evolved at a rate three times faster than humans, a metric derived from the diversity of the rat genome compared to that of the human. Despite the rat’s superior evolutionary speed, humans still possess superior intellect.

That being said, the adaptations emerging from evolution vary by species depending on the variables that impact the species’ survival. For humans, that variable may very well be intelligence, while for birds it might be more efficient wings. In other words, an individual species’ intelligence may be enhanced through evolution, but evolution as a broad umbrella across all organisms does not necessarily produce an enhancement in intelligence.

How Intelligence Works

Over the past century, scientists have studied human intelligence through the lens of a variety of hypotheses. Regardless of the approach, though, one thing has been certain: the human benchmark. If humans weren’t at the top of the list, then the analysis was most certainly flawed. This measurement has aided in weeding out some prior popular theories, especially as a direct correlation to brain metrics.

Size Doesn’t Matter

We humans are fond of comparing the sizes of our body parts. While most of those size comparisons fall short compared to many other species, the brain has been one that we could proudly display as a testament to human achievement. With such an impressive brain it is no wonder why the idea that sheer brain size determined intelligence floated around as an acceptable natural law for a while. That is, until other contenders entered the arena — notably, the sperm whale.

No, the sperm whale is not called a sperm whale because it looks like a top-heavy sperm cell. Sperm is comically short for spermaceti, which is a liquid found inside the sperm[aceti] whale’s head. It was a really valuable liquid for quite some time, because it was used in oil lamps, candles, lubricants, etc.

But enough about its comical name, let’s talk about the relevance — the sperm whale has the largest brain on the planet. But sperm whales are not (at least to current human understanding) smarter than humans. So what was that giant brain doing if it wasn’t trying to make the next breakthrough in quantum physics? As obvious as it may sound, bigger animals just need bigger brains to manage normal daily functions. In scientific terms, it’s called allometric scaling.

Allometric scaling only explains why bigger organisms need bigger brains, it doesn’t claim that a bigger brain results in greater intelligence. Either the assumption of brain-size-to-intelligence correlation was wrong, or there was a missing piece that must be added to the consideration in order to validate it. That missing piece was the brain-to-body ratio.

Brain Mass Vs. Expected Brain Size

The brain-to-body ratio metric as a measurement of intelligence has been floating around as mainstream truth more recently, similar to the myth that humans only use 10% of their brain (popularized by really awesome movies like Limitless and Lucy). But much like the 10% brain rumor, the brain-to-body ratio metric is also a flawed myth (that was once taken as truth).

This brain-to-body ratio is scientifically referred to as the encephalization (in-seh-full-I-zay-shun) quotient (EQ for short). Despite what may seem to be an intimidating name for those not fluent in Latin, the idea is simple and derives from allometric scaling (the correlation between body and brain size discussed in the previous myth). Allometric scaling tells us what a brain size should be depending on what a species’ body size is.

The EQ takes it a step further — e.g., what happens when the brain is larger than the size we expected it to be from allometric scaling. From the EQ, we expect that the larger the brain is in comparison to what is expected from allometric sizing, the more intelligent the species is.

Not to brag, but my encephalization quotient is huge.

Well, so is yours. Humans have the largest EQ of all similarly sized mammals: 7.4–7.8. Read that as: human brains are 7.4–7 .8x larger than what we expect a similarly sized mammal to have. The EQ hypothesis is seemingly validated by the fact that humans rank at the top.

But things start to fall apart in the middle. For example, a 2007 study of 25 primates concluded that orangutans are the most intelligent primate besides humans — more intelligent than chimpanzees and gorillas. Orangutans are the only primates that can communicate about the past. By EQ, Orangutans (1.9 EQ) rank above chimpanzees (1.7 EQ) and gorillas (1.5 EQ). On the other hand, they fall short when compared to the EQs of capuchin monkeys (4.8 EQ) and squirrel monkeys (2.8 EQ).

It’s What’s On the Inside That Matters

So far, attempts to correlate sheer brain size with intelligence (whether by size or by ratio) have not been successful. Experiments have turned to other theories, and we have now stumbled across one that seems to fit pretty well: it’s not about the brain size, it’s about what’s inside.

The powercells of the brain are the neurons. So maybe it’s as simple as counting the number of neurons, rather than looking at the overall size of the brain. Across all my research so far in trying to understand intelligence, I’ve come across many impressive researchers, but a psychologist named Suzana Herculano-Houzel stood out by far due to her unique techniques to linking brain composition and intelligence: making brain soup.