Humans love talking about their frontal lobes. Commonly considered the seat of intelligence and abstract thinking, these sirloins of the neural steak are thought to be the “most human” part of the brain. The human prefrontal cortex, the most forward part of the frontal lobes, is strikingly bigger than that of any other animal, which has led researchers to believe that the frontal lobes are what set humans apart in terms of our behavioural complexity.
The first major discovery of frontal lobe function occurred in 1848 when during a construction accident an iron rod shot through the head of a railroad worker by the name of Phineas Gage. When doctors saw the gaping hole at the top of Gage’s skull, his injury was unanimously considered fatal. But by some miracle, Gage made a full physical and mental recovery—or at least it seemed so at first. In the aptly titled report “Passage of an iron rod through the head,” Gage’s doctor, John Harlow, revealed that his patient’s personality had distinctly changed since the accident. Gage had gone from a rational, respected, and admired supervisor in railroad construction, to a childish and impulsive man with a hole in his head.
Gage’s injury offered the first major evidence on the role of the frontal lobes in personality and behavioural control. Since then, researchers have demonstrated that the frontal lobes are involved in everything from language to emotions to decision making. The PFC in particular is known for its role in executive functions. That means it’s responsible for planning, initiating, or inhibiting actions, for switching between tasks, and for abstract thinking. In other words, the PFC is a kind of boss for the brain, coordinating and planning activities and our attention toward them. We use executive functions all the time in things like problem solving, decision making, and reasoning.
Another part of the frontal lobes, called Broca’s area, is involved in speech production. In 1861 when French anatomist Paul Pierre Broca observed the postmortem brains of two patients who had lost their ability to speak, he noticed that a specific area of the left frontal lobe was damaged. This led him to conclude that the area was needed for speech production. More recently, researchers have found that Broca’s area is also involved in aspects of speech comprehension and gestures associated with speech.
Recent studies also show that the frontal lobes are linked with “theory of mind,” our ability to attribute mental states, beliefs, and attitudes to ourselves and others. Only humans and a few species of great apes seem to possess theory of mind, and in humans, this begins to develop around age two. Neuroimaging studies show that a part of the left frontal lobe is activated when participants consider the thoughts and feelings of characters in a narrative. Another study suggested that the right frontal lobe is particularly critical, especially in interpreting social situations and empathizing with others.
But some of the most fascinating frontal lobe research comes from studies that look at what happens when the frontal lobes aren’t working properly. For example, the frontal lobotomy, which involves cutting the connections between the PFC and the rest of the brain, was introduced in 1935. Despite the early lesson from Phineas Gage on the dangers of frontal lobe damage, the procedure was incredibly popular in the 1940s and 1950s, and became a standard treatment for psychiatric disorders. In fact, the 1949 Nobel Prize in Medicine was awarded to Egas Moniz for developing the first standard lobotomy.
By 1951, nearly 20,000 lobotomies had been performed in the United States alone. The popularity of the lobotomy was thanks in part to Freeman and Watts, the infamous surgical duo who developed the “icepick lobotomy.” This new procedure no longer involved drilling holes in the skull. Instead, the surgeon inserted a long thin instrument called a leucotome through each eye socket, and drove it deep into the brain using a mallet. The leucotome was then twisted around to essentially scramble up the frontal parts of the brain. Not a pretty thought.
The frontal lobotomy eventually declined in the 1950s and 1960s with the introduction of antipsychotic drugs. But that has not stopped researchers today from studying the effects of frontal lobe dysfunction. According to neuroimaging studies, patients with schizophrenia demonstrate less activity in the frontal lobes. The effect is seen especially during difficult cognitive tasks that normally activate the frontal areas in control participants.
It just goes to show that having a healthy brain means you’ve got to go full frontal. Lobes, that is.
