By Dr. Robert Thorson

We scientists can be terrible movie critics, especially for science fiction sagas such as “Star Wars.” Though we can appreciate the power of myth, sensory arousal, dramatic chase scenes and buttered popcorn as much as the next guy, our day jobs require we be on guard for natural phenomenon that just don’t make sense. Sometimes, however, science fiction is truer than science fact.

At least this was the case in 1980, when I watched the release of the second “Star Wars” epic. Everything was fine until Yoda appeared. He was portrayed as a wise Jedi master, yet his skull looked no bigger than a grapefruit, meaning his brain was fairly small. This contradicted the conventional science wisdom of the time, which held that large brains and high intelligence went hand in hand. This is what most baby boomers had been taught in school, that the evolution from ape to Australopithicenes, to Homo erectus, to Homo sapiens was accompanied by a steady increase in cranial capacity, and that this capacity is what made us smarter than your average monkey (never mind the fact that Neanderthals had big brains, too).

The ultimate insult at the time was to be called a pea-brain. In fact, fraternity boys getting C’s felt smarter than sorority sisters getting A’s simply because their brains were larger (never mind the fact that elephants had bigger brains than both). This big-brain/ smart-guy connection was reinforced by the Hollywood norms of my youth, which portrayed science fiction aliens as top-heavy creatures; all brains, no body, so to speak. By this standard, the science fiction Yoda was a bottom-heavy dullard.

But George Lucas had it right. The scientists had it wrong.

In the spring of 2005, we’ve learned that the tiniest human species of all — Homo floresiensis — was probably a smart one, at least for the scientists who reviewed a study published online by the journal Science. Though officially named for the bones and stones discovered on an Indonesian island, these human “hobbits,” as the scientists have nicknamed them, had chimp-sized brains, yet were smart enough to make fancy stone tools and to hunt alligator-sized lizards. For the study, the investigators made a cast of a hobbit’s brain. The skull was too fragile to do this the normal way, which is to pour liquid latex rubber onto the mold, let it stiffen, then pull it out, yielding something like those rubbery Halloween masks. Instead, they made a virtual cast with radiation tomography, which synthesizes thousands of measurements into a complex three- dimensional image. They did the same thing with other skulls from a modern woman, a pygmy, a chimpanzee and a microcephalic modern human (a condition leading to mental retardation). The tomographic casts were then compared with latex casts of extinct hominids and other primates.

The results were stunning. In spite of its diminutive size, the brain casts of Homo floresiensis exhibited three advanced anatomical features. Its temporal lobes, a region of the brain associated with language, were greatly enlarged. Even more stunning was the convolution of the frontal lobes, a feature that gives rise to increased brain surface area and which is associated with advanced cognition. Finally, the most convoluted part of the brain — something called Brodmann’s area 10 — is the one associated with executive function, the ability to think and plan ahead.

The take-home message is clear. Brain size may be crudely correlated with intelligence, at least on the continuum from garden slug to gorilla. But on the evolutionary line that includes Luke Skywalker, Princess Leia and Yoda, it’s the brain structure that counts, not the brain volume.

I first met these characters more than two decades ago. Since then, Lucas has given us one fine sequel after another. Taking a cue from his success, I decided to try a sequel of my own. Part 1, titled “Fossils From Out Of Left Field,” was published on Nov. 4, 2004, and reported the initial discovery of Homo floresiensis. Part 2, this column, is my sequel, reporting on the high intelligence of these human hobbits. Looking ahead, I’m wondering if next year will bring another study linking their small brains to a Yoda-like body. At that point, I would be willing to concede that science truth can indeed be stranger than science fiction.