What Makes Us Special: The Evolution of the Cortex and Memory

Last Sunday, as my parents and brother talked about their upcoming trip to Disney World, my mom asked me if I remembered much from my trip to Disney at 3. I replied in typical psych student fashion, that unfortunately 3 is the time when you’re first forming memories and that I read recently that by the age of 7 you start losing your earliest memories, so no.

Apparently I met these folks, I've got their signatures. That's about all I have. source.

Apparently I met these folks, I’ve got their signatures. That’s about all I have.
source.

Fact is that I can’t really remember what courses I am currently enrolled in some most days. This strikes me because  throughout my university career I have been told that our memory capacity is virtually limitless. And yet giant limits appear in our long term memory. Memories are constantly fading for me, for everyone, which is explained as a sort of use it or lose it principle. My professors assure me that the memories are all still there, it’s just a retrieval issue, but really, the result is the same. What good is my car still being in the secure lot if the valet driver is unable to get it for me? How can they argue that our memory is limitless if we lose our childhood memories. The most sweet and innocent times of our lives, the moments where we are most curious and interested in everything, and we forget what it was to wonder at the world. We lose the ability to recall many events, even the big things, we may recall some details but there a number of chunks missing. Add to this that the memories we do hold onto are neither necessarily wholly accurate nor wholly complete. We tweek things, omit certain things, incorporate false details (it’s a thing, they’ve done studies), and at the end of the day we still call it a “true memory”.  Since we are biologically driven to pay attention to certain stimuli, we can miss big things in the environment…

Exhibit A:

See the ape? (if you’re a psych major or have seen it doesn’t count) How about the changing colour of the curtain? AND the missing player?

I rest my case.

Thanks to the power of emotion in creating memory, we often remember the exact things we wish we could forget – the moments of complete and utter heartbreak and loss, but for some reason can’t remember which room of the house we left our cell phone in.

Seems pretty limited to me…

Way back, maybe not quite as far as the dinosaurs, early hominid species roamed the earth. According to the evolutionary theorists, these guys and gals were guided by pure instinct. They ate because they were hungry, had sex because of advantages of the match and because of pheromones and such. We fear snakes today because of those guys apparently implanting these fears in our genes.

Not quite this far back..

Not quite this far back..

...maybe like here....  Source.

…maybe like here….
Source.

I’ve been exploring what makes humans unique for a several months, even stumbling across an absolutely enthralling TED talk on what makes our brain so special (hint: We learned to use a frying pan as more than a weapon).

When you get down to it though, beyond the whole bipedialism, differentiation of the cortices of our brain and other markers, what makes homo sapiens “man the wise” is our frontal cortex. We won the evolutionary lottery and somewhere down the line something went wrong, and bam! We have this massive frontal cortex and can now imagine things, do trial runs in our mind, formulate a future in our head without ever lifting a finger. And that’s incredible.

Just think about that for a second because it’s got some big implications and can lead to some incredible thoughts

  1. Something went totally wrong in the genetic part of breeding, and it was the best thing that happened to the hominids. It allowed us to form more complex social structures and to … well think outside of the current state of things. We could now grasp objects metaphorically speaking with our hands, understand things that could not be perceived. A lot of things are like that with humans – blue eyes are a mutation, our opposable thumbs were probably a mistake somewhere in the code, in Africa there is a mutation that protects individuals from sickle cell anemia, but hey stuff happened and it worked. So yay for serendipitous mistakes.
  2. Recent media attention has been dedicated to the issue of genetically modified plants and the fear that, like in the 1997 movie Gattaca, we will move towards designer babies and genetic discrimination. And I think that when you orient your view to this whole idea of mistakes as potentially beneficial, this issue becomes even more interesting. Genetic modification of plants has increased crop yield and holds a lot of potential, so the question becomes – are mutations and modifications a benefit or are we preventing the best things from happening? Also, how are these genetically modified plants affecting us epigenetically (fancy science word meaning are they changing our genes through gene x environment interactions, REALLY cool stuff!)? Are we in the process of evolving into a new homind species?
  3. What happened before this frontal lobe came to be so big? The hippocampus is one of the primary areas for memory, but it’s in one of the oldest parts of the brain. All mammals have a hippocampus, even non-mammals have analogous structures. So we…had a place to store memories?… But they were somewhat useless to us? The hippocampus is present and functioning in even lower animals – your cat has a hippocampus, and yes, science thinks it’s involved in memory in cats too. Our prefrontal cortex evolved as we progressed through the hominid evolution, and it grew and allowed us to plan in a much more sophisticated way. What about when it wasn’t evolved though? I’m not saying that I think we were completely useless, but if my memory and planning abilities are still fairly flawed, I shudder to think how much trouble the Australopithecus robustus was in.
  4. Our memories became so much more useful as the neocortex grew. Homo Sapiens have much more white matter than previous hominid species  Essentially this is how we learn, we take the information and add connections, we use what we experienced and heard in the past to build on and expand the information. Can you imagine how little you would accomplish in a course if every time the professor started the lecture he or she had to review all the content previously covered. We would get no where. I am of course being mildly hyperbolic, but it logistically follows that if throughout evolution the neocortex has increased both in size and connectivity, then earlier species were up a bit of a creek without a paddle. Not that they knew it really. They didn’t think to pack the paddle really.
  5. In a sense, this ability to see beyond the present has handicapped us, created a new problem in solving another. In a sense, it is why we developed internalizing disorders such as depression and anxiety. In a way this ability to imagine gave us not only the ability to imagine innovations like the wheel, cell phones, and sliced bread, and a bigger, better world, it also gave us the ability to imagine the not so rosy world. It allowed us to ruminate on disappointments and manipulate the future into a terrifying and depressing world. But it is also our big beautiful frontal cortex that allows therapies to work. We have the power to change our outlook, we are no longer slave to instinct, but this freedom means that we sometimes can see too much or too little and think we’ve seen reality.

So recap what fresh horrors have I meditated on this week?

  • The structures for memory were developed a lot sooner than the structures for planning and using those memories.*
  • Our “limitless” memory is limitless only in theory. Where this theory came from I am not really sure.
  • Sometimes progress looks a bit like a mistake.
  • I’m really hoping that based on the state of my memory that evolution isn’t done yet.

On that last point – you may wish to watch this video:

*As a side note – if you’re interested in the topic – this is a fantastic article, that discusses how our short term memory strategies were shaped by the development of language! Really cool stuff. If you’re really interested! I have heard some fantastic things about The Rise of Homo Sapiens: The Evolution of Modern Thinking.  

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