Kolb – prefrontal cortex

So, the question is why do animals have a prefrontal cortex, why is it bigger in people, in humans than in other species, and the thing we have to recognize is that the prefrontal cortex was not selected by nature, behaviour was, behaviour that the prefrontal cortex is engaged in. So now you say well what is it that the prefrontal cortex’s function is that was being selected for, which made it bigger. One of the things it does is it clearly is a way in which you can take all sorts of sensory experiences and put them together and make a single, unifying theory as to what’s going on. So if I’m wandering around the world I’ve got visual experiences, auditory experiences, tactile experiences, I’ve got experiences that are internal, memories, things from the past, thoughts about the future and so on, how does it all fit together? How do I make some sort of story up about the world? The more complicated the information is that’s coming in, the more complicated the prefrontal cortex is going to be. So we know that as the number of sensory areas increases in evolution, and it does, so if you look at rodents versus primates, the number of visual areas goes from three or four up to 20, 25 visual areas. That’s a huge increase. So obviously whatever we’re doing with visual information, we’re really making the visual world more complex. The world we’re creating is more and more complicated; the frontal lobe increases in lock step with that, so the prefrontal cortex increases with it.  

So as that frontal lobe has gotten bigger and bigger, our schema that describes the world has gotten more and more complicated. One of the real complications is what I’ll call autobiography. So if I said to you, tell me something that happened to you in grade three, you can not only tell me that you went to in my case Glengary school in Calgary, but you can tell me, well, we used to have fire drills and air raid drills and these were some things we did and I remember this experience that happened. I can also go in the future. That’s autobiographical information that happened in the past, I can also say well what do I plan to do? I’m 65, what am I going to do when I’m 70? What’s my plan? I can actually give you that plan. I’m willing to reckon that a chimpanzee who’s got a pretty big frontal lobe does not have the capacity to recall a specific memory, although we can’t really tell, from when it was young, that’s a hard thing to determine, but I’m pretty darn sure it doesn’t think about tomorrow very much, whereas we have this unifying element of time, past, present, future, that’s in the frontal lobe, that’s a unique sort of emergent property that we have. If you start messing with frontal lobe, you can lose that. You can lose the capacity to plan, for today or tomorrow. You can lose the link with the past in which case you cannot actually identify unique experiences that you had. You can identify experiences about, let’s say grade three in my example, but you’re not so good at identifying ones that relate to you. If you can’t relate to you, and this is clearly going to make a difference as to how you relate to things in the present and in the future, so that’s what the frontal lobe changes are about.