18 Aug When we feel confused we turn to philosophy (FRAZZETTO GIOVANNI)
So, for many centuries, rationality and emotionality were considered two opposing properties of the brain, operating as competing territories. They were like two substances that repelled each other and never mixed, rather like oil and water. The rational brain helps us analyse facts and assess external events, while the emotional brain tells us about our internal states. During the past two decades this rough division of labour in the brain has been challenged. The brain’s geographical boundaries as regards the accomplishment of rational tasks and emotion have blurred. The prefrontal part of the brain still holds the reins of rationality, but it also contributes to emotion.
This crucial and fascinating reversal in the understanding of the role of emotion has been underpinned by experimental work, particularly that of neuroscientist Antonio Damasio. Before we consider this, I need to tell you a story.
The story concerns Phineas Gage, a 25-year-old American who in the mid nineteenth century worked as a railway construction foreman and suffered an unfortunate and unusual accident in the course of his duties. Since new rail lines needed to be laid across the state of Vermont, it was essential to flatten the uneven ground and Gage was responsible for carrying out controlled explosions. The procedure was relatively straightforward: Gage had to first drill holes in the ground, fill them with dynamite, insert a fuse and lastly push a tamping iron down the holes after the explosive powder had been covered with sand. On 13 September 1848, because someone called him and he briefly turned round, something in the protocol went wrong. Gage started to tamp before one of his assistants had applied the sand. This was a grave mistake, because, without the sand, the explosion spreads away from the rock. The result was that the tamping iron, over a metre long and three centimetres thick, blew out and went right through his head, exiting from his left cheek, before it rocketed into the sky and fell to the ground several yards away, leaving everyone present astounded.
It’s hard to believe, but Gage survived. Remarkably, after momentarily losing consciousness, he regained it immediately after the accident. And, after a few weeks of convalescence, he recovered fully. His language and intellectual capabilities were entirely unaffected. He could walk, run, talk and interact with people and even go back to work. Over time, however, everyone noticed a few changes in his personality.
Before the tamping iron penetrated his skull and brain, he was unanimously regarded as a considerate, loyal and friendly man by his peers. At work he was praised as one of the best and most efficient workers, the company’s favourite. However, after the accident and as early as his convalescence, he had bursts of anger, became impertinent and impulsive and lost his capacity to judge the social acceptability of certain of his ways of behaving. He became unreliable, offensive and irresponsible towards others. Eventually Gage was left isolated by his friends and acquaintances. He lost his job and never found another. Having descended into a desolate existence, he died a dozen years later.
This tragic story is scientifically compelling in that it demonstrates the links between brain damage and behaviour, in particular social and moral behaviour. Gage’s case showed that compromising a fraction of the brain can have serious and noticeable consequences on a man’s personality. His skull and the infamous tamping iron remained on display at the Warren Anatomical Museum at Harvard University and, remarkably, for a long time they did not receive the attention they deserved. In the mid 1990s Antonio Damasio and his colleagues at the University of Iowa College of Medicine decided to examine the skull to reconstruct the accident and closely map the brain areas where the lesion occurred. They established that the tamping iron had specifically damaged the ventromedial part of the prefrontal cortex. This was an important clue. Damasio had met other patients with similar lesions and comparable behaviour. So he set about investigating them.
One of the group’s first experiments that helped identify the role of emotion in decision-making focused on gambling. Not everyone is a professional gambler, but we all face decisions that require the assessment of risk and of potential gains and losses, as well as choices that may conceal harmful, counterproductive and irreversible consequences. Such are the uncertainties of life.
Damasio and his colleagues gave the players in the gambling experiment a starting sum of $2,000 and four decks of cards, asking them to draw from any of the four decks. Each card drawn revealed a reward or a request to hand over an amount of money. The ultimate goal was to end the game with the highest profit. A secret pattern lurked among the cards. One pair of decks contained cards with the best rewards, up to $100. However, this pair also included cards that requested the gamblers to hand over equally large amounts of money. So, while these two decks gave the impression of being profitable, they also carried the highest risks. At first sight, the gamblers had no way of telling when an unfavourable card would turn up. By contrast, with the other two, less treacherous, decks of cards, the highest win was only $50, but the losses were never harshly punitive. Overall, drawing from the low-win decks would prove more profitable.
The gamblers in the experiment consisted of two groups: people with their brains intact and patients with lesions in their medial prefrontal cortex. Like Phineas Gage, the latter experience difficulties in taking decisions. Damasio realized this when, for instance, he invited them out for lunch and asked them to pick the restaurant. Testing Damasio’s patience, they would spend more than half an hour reciting the pros and cons of several restaurants. One, they warned, had good prices but was always empty, so it might not be too good, but, on the other hand, it was more likely to have a free table; another was pricey but had generous portions. In the end, despite all their lucubration, the patients couldn’t make up their minds. One of them, whom Damasio named Elliot, was a bit like Gage. He was an otherwise entirely intelligent, pleasant and charming man with a sharp memory, but he was unable to hold on to a job, keep a wife or plan his time properly. He acted foolishly and irresponsibly and could not be trusted.
Anyway, back to the experiment. As the gamblers carried on playing, an important hint that made Damasio suspect the involvement of some kind of emotional arousal in their choices came from their bodies – to be precise, from their skin. Attached to each gambler’s skin was a machine that measured changes in skin conductance response, or SCR. SCR is a sophisticated expression for sweat. If you are nervous or stressed, or in general emotionally stimulated, one of the things that happens to your body, even if it is not perceptible to the naked eye, is that your skin sweats slightly. In a laboratory, this can be measured as it happens. Over the course of the game, the gamblers with intact brains preferred to pick cards from the advantageous decks. At a conscious level, they didn’t know exactly what was going on or why it would be wiser to take that decision. But their bodies did. As measured by the SCR, each time they picked from the risky decks, fear emanated from their skin and that emotional edge guided their choice towards the less hazardous decks. On the contrary, as you would expect, the judgement of the patients was less sharp. When their hands reached for the more punitive decks, there was little or no skin reaction. They kept drawing cards from the bad decks, even when they started to realize how harmful they could be.
So, failure to experience the emotional cues of a situation results in poor deliberation.
Not only was emotion important in guiding a decision, but in a way it already knew which was the best decision to take, and took it first. Call it intuition, a sixth sense or just plain foreboding. Whatever it is, it helps reason to make a choice.
Damasio’s hypothesis is that this intuition is actually finely etched in our brains, like grooves of a song incised on a vinyl record. In fact, he calls it the ‘somatic marker hypothesis’ (the Greek word soma means body). Each time we face a situation, we register its positive or negative emotional charge. It’s as if we stored emotional knowledge in our brain. The behaviour in the game of the two kinds of gamblers suggested that the acquisition of this knowledge must somehow require a functional prefrontal cortex – in connection with the limbic brain – and that, in possession of this knowledge, the prefrontal cortex works like a guide that controls our actions. Indeed, the acquired information becomes precious knowledge for when a similar situation arises again. The harsh losses they incurred taught the gamblers with intact brains about the risk of drawing from the bad decks. The gamblers with lesions in their medial prefrontal cortex could not register, nor retrieve, that information, and so kept making the same mistake.
In real life we face countless situations in which emotional knowledge comes in handy. These range from relatively simple choices, such as which colour to paint the living room, where to spend a holiday or which painting to buy, to more committed decisions about who to date, which property to buy or whether or not to accept a job offer. In each of these cases, emotional hints can guide our actions. It’s almost as if the grooves of that once-incised song play a warning sign silently in our ears, suggesting what we should do.
Damasio’s ground-breaking experiments entirely revised the predominant theories that confined decision-making to the realm of rationality and established a new theory according to which emotion is essential in decision-making and our most seemingly rational choices. Emotion and reason are not two exclusive functions of the brain. There exists a mutual dependency between the two. Relying on the computational qualities of your brain makes you develop sophisticated analyses. But, as Damasio’s experiments show, you would not be able to take any good decision. In extreme cases, no decision at all. You would be blocked or lost in the careful assessment of the myriad advantages and disadvantages of each option, just like those patients who couldn’t make up their minds about the restaurants. It does happen from time to time that we take decisions without being able to provide the ultimate explanation for having taken them. Emotion helped us take them, unconsciously, behind the foreground of rationality. So, emotion makes its own judgement, as it were, and has equal authority to rationality. In fact, reason can’t operate without emotion’s persuasive advice.
But what these experiments also did was to remap the fixed geography of brain function. They showed that a region in the prefrontal cortex, which everyone believed was exclusively responsible for the analytic, logical duties of the brain, does indeed participate in emotion. Without it, the emotional edge that contributes to decision-making somehow can’t be integrated into the process.
Joy, Guilt, Anger, Love : What Neuroscience Can–and Can’t–tell Us About How We Feel
Frazzetto Giovanni
