Introduction

Now that we’ve discussed what it is like to be inside your mind, we will discuss what it is like to be inside your brain. In this chapter, we’ll describe the broad structures of the brain, and then focus on a region particularly relevant to cognition: the prefrontal cortex.

A Brief Introduction to Your Brain

Figure 2.1 is a diagram of a human brain, with a few key areas labeled. The whole of what you are looking at—that wrinkly, outer surface of your brain—is what we call the cortex. We can divide the cortex into four chunks called lobes. The frontal lobe is at the front of your brain and is responsible for a variety of functions related to cognition, motion, and emotion. The term prefrontal cortex refers to the very front of the front—specifically isolating the more cognitive, less motion-oriented bits of the frontal lobe.

The parietal lobe, just behind the frontal lobe, is where you process the sense of touch, as well as the planning of motions, visualization of spatial relationships, and more. The occipital lobe, in the very back of your brain, is almost exclusively for visual processing. The temporal lobe, by your ears, processes hearing, language, object recognition, and memory.

There’s another important chunk of the brain that we can’t see in Figure 2.1, because it’s in the middle! You need an inside view of the brain to see the limbic system.

The limbic system is our term for a collection of brain regions that perform functions ranging from memory, learning, emotional processing, sensory processing, hormone functions, habits, and motion. That’s a wide variety of things, but don’t worry, we’ll discuss specific regions as they become relevant.

Phineas Gage

You may have heard of Phineas Gage. He is known in the psychology world for a terrible accident (unfortunately, this is a common way to become known in the psychology world). One afternoon in 1848, he was working on a railroad in Vermont when a small explosion caused an iron rod to blast through his head.

Miraculously, Phineas Gage survived. The rod had torn a hole through his head, and indeed, torn a hole through his brain, but it didn’t kill him. Why?

You’ll notice in Figure 2.3 that the rod injured Gage in the front of his head – and the front of his brain. Indeed, the brain region that Phineas Gage lost in this accident was his prefrontal cortex. This is our first important fact about this very special part of your brain: you can (sort of) live without it! This is not the case for all parts of your brain. You usually can’t, for example, survive extensive damage to the parts that control your heart rate and breathing.

While Phineas Gage survived the accident, everything didn’t go right back to normal for him. Instead, people around him reported a change in personality. Before the accident he had been a capable foreman. However, after his injury he was unable to hold his old job, and was rash, impulsive, and unpleasant. He no longer seemed to be “himself;” his personality had changed – for the worse. This is our second important fact about the prefrontal cortex—you need it for decision-making and regulating your personality!

We should note, before we leave Phineas to his eternal rest, that there is mixed evidence surrounding his alleged personality change. It’s hard to verify the reports that his behavior became erratic and terrible after his injury, and there is evidence that these issues improved over time. We must also consider the fact that he experienced something very traumatic, with a grueling recovery period, that probably also factored into his future life experiences. He died twelve years after the accident of prolonged seizures. He was only 36 years old.

While the exact details of how Phineas Gage’s injury affected him may be lost in the past, his case became famous and has been consistently used to demonstrate facts about the brain for years. Let’s take the two most important points (you can survive damage to your prefrontal cortex, and it influences your personality) and move forward into the 1900s, where we’ll explore a deeply regrettable chapter in the history of psychology.

Lobotomy

In the 1940s, a new technique for addressing psychological problems emerged in Europe and the United States: lobotomy. Motivated (at first) by a desire to “cure” mental illness in patients, doctors performing a lobotomy would cut tissue in a patient’s frontal cortex. Sometimes, they accomplished this through surgery (anesthetizing the patient and cutting a hole in the skull), and other times, they simply used an icepick to pierce through the thin bone behind a patient’s eyes to reach the brain. Either way, this was a brutal and imprecise procedure. Worse still, lobotomies never accomplished their intended goal.

Now that you know a few things about the frontal cortex, you can probably guess what damaging it in such a way might do. Often, patients subject to lobotomies underwent a change in personality and behavior: they might lose their capacity for self-control, their goals and desires, their emotional expressiveness, and in some cases, their entire conscious experience. Not only are these consequences not a cure for mental health problems, they are also explicitly harmful.

Luckily, lobotomy is now considered a cruel and outdated practice. However, we cannot forget this chapter of cognitive psychology. For one thing, lobotomy has confirmed what Phineas Gage’s accident suggested: while you might not need your whole frontal cortex to live, you probably need it to be you. More importantly, however, lobotomies remind us of the damage humans are capable of when we get too carried away. While they might have started out as an attempt to help people, lobotomies in many cases turned into an instrument of control. As we move ever forward into new horizons of science and technology, we must always bear in mind: what’s our motivation?