Human Brainpower Bested

Sometimes I think we humans suffer from deep feelings of inferiority, because we so often tout reasons for our being best, or belonging to the better group. It's as if we are trying to convince ourselves of being superior, by expressing that my religion is better than yours, my team is number one, my kid is at the top of her class, and other such bolstered beliefs.

We especially fall into this game of snobbish notions when we compare humans to animals. Several hundred years ago it was an unquestioned conviction that we were absolutely superior to animals. We had utter faith in the divinely-created hierarchy, that placed God at the top, angels and other celestial beings next, humans next, and all the animals at the bottom. The major source of our supremacy was believed to be our brain—clearly larger and more complex than any other critter. And look around you... don't we dominate the planet? Is that not proof that we are number one?

That sense of superiority has been hard to deflate, but science has gradually been chipping away at our edifice of arrogance. Recent research is discovering many ways in which features of some animal brains, in fact, best ours. Here are a few examples.

Neurogenesis is the process of growth of new neurons, and thus compensates for the loss of neurons as a critter ages. Only in recent years have neuroscientists shown that we human oldsters do indeed create new neurons—though we get increasingly slower at doing so as we age. Yet we're bested by several animals, including some species of fish, who perform neurogenesis about 100 times faster than we do.

Secondly, we pride ourselves on our good memories, but chimps do much better at remembering. So do some species of birds and squirrels, who stash thousands of seeds in times of plenty, and then remember the locations, months later.

Thirdly, our sense of smell—a key brain function—is quite inferior to many animals, because that part of our brain (the olfactory bulb) devoted to smell is relatively small. A bear's olfactory bulb is five times the size of ours—even with a brain that is one-third the size of ours. The super smellers—sharks--devote one-third of their entire brain just to detecting smells.

Fourthly, our brain weighs about 2.5 pounds (1.2 kg). That is quite large, compared to our ape cousins, but a dolphin's brain weights 3.5 pounds (1.5 kg). And we are dwarfed by elephants and whales, whose brain weighs 11 pounds (5 kg). Now, brain size is not the sole governing factor... the brain-to-body mass ratio is a better measure, but even there we are overshadowed by our ocean-dwelling cousins.

Fifthly, without our GPS software on our smart phones, we are lost. Many folks today cannot even make use of a map.  Birds—especially pigeons—possess brain cells that are sensitive to the Earth's magnetic field. Rain or shine, sunny or nocturnally, they know their geographical location.

There are several other examples of how animal brains surpass ours, but that’s a good overall view. We may be the smartest (when is the last time you read about a pigeon winning at Jeopardy!?), but we trail animals in many brain functions. It might be useful for us to cultivate a little humility and recognize those brain functions where we are bested by the beasts.

Adult Absentmindedness

As I have aged (I recently entered my 75^th year), I have increasingly experienced a phenomenon that most anyone over 50 can attest to: there is a chunk of memory, say, a word, that you are positive is stored deep in your brain, but at the moment refuses to be recalled. You are either thinking to yourself or talking to someone, and in mid sentence, the next word just won't come. It can be a minor irritation or it could seriously rattle your cage, as the threat of Alzheimer's comes to mind... but not that damned word!

My wife and I know each other well enough by now that we can usually save our spouse fretting over such a brain fart, by supplying the missing word for the other. That's only a minor consolation, however, since the affliction seems to continue to grow as we age. Maybe we can try learning how to read minds.

I decided to grasp onto a little consolation a few years ago, when I conjured up the notion that my brain is not deteriorating—it's simply the case that I've continued to cause it to soak up so much new and wonderful information that it's become fully saturated with knowledge. As I add more new things, some of the old, stale things necessarily get pushed off my mental plate—they get purged from my memory banks. Although I liked the sound of that notion, it really was little comfort, since I had to admit that it might just be wishful thinking.

Then I was rescued this last spring, when researchers announced that they had discovered the cause of something dubbed “infantile amnesia.” Although this refers to a person's general inability to recall events before about age three, the process can also occur later in life, the scientists said. The cause (the culprit): something called “neurogenesis”—when new neurons in the brain rearrange its connections and destabilize existing memories.

We humans are born with an incomplete brain. (If it were any more complete than it is at birth, our head would be too big to squeeze through mom's birth canal.) So, in the first few years we grow many new neurons at a rapid pace, as our skull doubles in size. All this new gray matter disrupts existing neurons, trashing some of those early infant memories.

So what about us elders? Up until a few years ago, neuroscientists believed that an adult brain cannot grow new neurons—only kids can. Now we know that's not the case. We old farts can do it too.

Where does this leave me (and countless other elders)? Well, if we are able to generate new neurons, there's the possibility that they then muscle in and trash some of our earlier memories. Aha! That's why I can't remember that word! My earlier notion that new knowledge is pushing some old memories off my mental plate is not so unlikely after all. OK, so I lose a few memories: but look at all the new ones I can gain at my age!

Now... what was that next neat idea I was gonna write about...?