In this short lecture I'll pay attention to the evolution of the human brain. We're going to examine how understanding the structure and function of the brain as a result of evolution can be important for understanding large scale of human history. Much of our history has been hinging on personalities, such as those of emperors and monarchs. But also on social and economic interactions, affecting geopolitical factors, like mass migration. Once personality is made up psychological traits and in turn this traits largely depend on processes in the brain. We know for instance that emotionality and impulsivity are to a great extent determine by the functioning of the most frontal part of the brain. The so called prefrontal cortex together with structures deep down inside the brain. The basal ganglia Let's consider for instance the third battle of Ypres. A town in the southwest of Belgium that became the stage for some of the most bloody massacres of the First World War. This war campaign is also called the Battle of Pasendawn. It happened in the Fall of 1917 and took the lives of over half a million soldiers. The British Supreme Commander, Sir Douglas Haig wanted to create a gateway for the Allied Soldiers to break through the German trench lines and move up to Brussels. But the campaign failed miserably the allies moved up only four kilometers. What makes the third battle of [INAUDIBLE] so interesting from the brain view point, is that it was already the third battle of that kind and in this region. Also, the two previous battles of Ypres Salient took a huge toll in casualties, brought minor gains, and were fought under much the same conditions. Soldiers running from one muddy trench to the next one, facing heavy machine gun fire from well-defended enemy positions. So, why did Dr. Hagan is commanders take the risk of another big failure? Let us look at this question from an evolutionary point of view. Here, we see a tree branching out with early mammals at the stem of the tree. And then the higher branches of two rodents and carnivores like cats and up there the branches of monkeys, great apes and humans. In colors, we see the size of the sensory areas of the cortex. The cortex is the concluded part of the brain that you see when this color opens. If we go even further back in time, we arrive at ancestors that gave rise to today's vertebrates, like fish and mammals. A candidate ancestor creature was Pikaia, from the Cambrian, which was already bilaterally symmetrical with a mirror image of one body side to the other. Such animals move their body in one direction and therefore the front part of the body is the part where most of the excitement occurs. This is where food is encountered and must be explored by smell and tasting. Where also the chewing and swallowing must occur, it's also the best place. With a good few on the upcoming surroundings where your heading. So, the better place to have enough ears, and eyes, around this friend's butt. So, in short this is how cephalization developed throughout evolution. Formation of a hat with a mouth, and a lot of sensors and actuators With this came sophisticated control circuitry. For instance, to track objects in the environment. The ability to move your body forward while keeping a stable view and a focus on an object that passes by. Why you have eye movements that are adjusted to the speed of your body motion. In fish, amphibians, and reptiles we find a vast tracking and orienting abilities. Having their origin in the so called techtum and basilginglia. These brain structures command a basic kind of decision making which takes care that brain does not initiate to opposing kinds of behaviors at the same time, like free and fighting at the same time. But, these brains have only a limited ability to adapt to new circumstances to learn from experience and use the experience to produce smarter behavior. These species do not have a great ability to plan complex sequences of actions ahead in time. They lack the kind of deep understanding of which chains of events in the complete environment are causally important for getting foods and liquids. For more sophisticated planning behavior we have to study mammals and birds. For instance, Caledonian Crows can perform a sequence of actions such as bending a hook to retrieve a hidden food item. And rodents such as rats show evidence of planning and deliberation in their behavior. As they carefully weigh choice options in this figure-eight maze against each other, and compute the most advantageous decision for getting food rewards. Nowadays we also use electrode arrays to record electric activity from groups of neurons in their brains. And these studies show indeed that there are arona\g groups that signal planning processes in the brain. Before taking indecision, certain brain structures in the rats will play out these various options ahead of where the animal actually is. And these structures are important for memory as well, and motivated behavior. Structures such as the so called hippocampus and stratum. Many birds and mammalian species living in social groups which requires careful planning as well. Before you make a sensible plan you need to understand the social relationships in your environment and your brain needs to build a model or tree structure. In which such relationships and other causal elements in your environments are laid down. In general, a key brain structure for building such models that enables us to make the best predictions and pick the best actions Is the neocortex. During evolution from early mammals to monkeys and huminites the neocortex has been hugely expanding, especially the parts sitting at the front of the brain. And so if we turn to Sir Douglas Hick and his commanders at the Third Battle of Eber we ask again why this massive failure? Of course we cannot peek into Haig's mind and it's often been said that commanders of the armies there did not appreciate how much all that mud would delay any progress. And it's also hard to escape a more general conclusion about the First World War, it's the repetitiveness of the battle strategy. The shear recurrence of trench assaults, that points to a certain perseverance and lack of adaptiveness. On both sides of the front, armies had to learn yet, to cope with the relentless fire of machine guns. Their impact, the commanders had not yet internalized this new technology into their models of warfare. So the human brain is grand and flexible but in a way we're also captives of our primitive brain. A brain that evolved to cope with local and personal interests. It's a brain that is poised to generate action even if there's no sound strategy underlying it and it's not a brain that evolved to think globally. Also in today's world, we have to cope with our locally oriented brains somewhat myopic to the long term future, but still deciding about billions of people.
