A misconception many people have is that our brain is physically divided into two parts, but this is not the case. The idea of left-brain and right-brain thinking is persistent, and many people continue to believe that the left side of the brain is responsible for analytical thinking, whilst the right side is more creative.
It is easy to understand why system 1 and system 2 type thinking have been mistakenly associated with this idea. These ideas are fundamentally incorrect, however. The brain is not physically divided in any way and as such system 1 and system 2 type thinking cannot be physically divided either.
This debunks our first myth. All this being said, neuroscientists have found that some regions of the brain are slightly more associated with one of the two systems [5]. For example, this body of evidence indicates that affective cognition system 1-type thinking for emotional responses is located in the mesolimbic dopamine reward system. This pathway is responsible for the release of dopamine.
The separation of brain functions for decision-making and perceived specialisation has given rise to the multiple systems hypothesis. However, it is important to note that it is the combination of information gathered from the multiple systems - mesolimbic pathway, frontal cortex, and parietal cortex - that help to produce our decisions.
In other words, whilst different regions may be more or less relevant for either system 1 or system 2, neither hemisphere is restricted to solely system 1-type decision-making and the other for system 2. Another myth or common misconception is that system 1 and 2 are hierarchical processes with one occurring before the other. In more general terms this means that people often think system 1 thinking occurs first and system 2 thinking following later if necessary.
The dual-system approach actually imagines the two forms of reasoning as integrated and mutually supportive. Indeed, Kahneman points out that almost all processes are a mix of both systems, and it is important to emphasise that the systems are complementary. Importantly, unconscious processes such as emotion system 1 play a vital role in our more logical reasoning system 2 , and it is this integrative approach that makes our decision-making meaningful, and often more effective and purposeful [7].
The philosopher David Hume, for example, recognises the importance of the heart system 1 for the head system 2 in decision-making as reason alone rarely provides any clear motivation and drive.
Without emotion or feeling, reason is merely a cold, mechanical method of calculation; informing us of what the consequences of our actions may be, but not whether they are desirable.
Ellen Peters and her colleagues provide further evidence of the mutually supportive nature of system 1 and 2, demonstrating how decisions are most effective when drawing from both systems. They conducted an experiment in which they gave participants tasks that required processing numbers.
Unsurprisingly, participants who had high levels of numeracy outperformed those who were less numerate. Numeracy has been previously linked to an improved ability to use system 2 reasoning effectively. However, they also found that participants with great numeracy skills were also able to use system 1 reasoning more frequently and reliably. Importantly, they also found that over time, the consistent and effective use of system 2 reasoning calibrates system 1 processing making that more effective, which in turn promotes better systematic system 2 reasoning, essentially creating a feedback loop.
These findings suggest that the two systems do not work in isolation but are in fact integrated and mutually influential on each other. Outside of an experimental setting, everyday tasks provide further evidence for the teamwork of systems 1 and 2. Physical activity is another. Recent research suggests that exercise is partly habit-driven, yet also requires conscious oversight to be successfully completed [8]. We can also see the integrated nature of systems 1 and 2 in tasks such as driving a familiar route, typing, or playing a well-rehearsed tune on an instrument [9] , all of which require a combination of deliberate and automatic action.
Whatever the reason may be for the development of this misconception, it is in fact, a myth. It is not the case that system 1 is biased and system 2 is not. If modern primates are anything to go by, their ancestors likely lived in groups. Mastering the social niceties of group living requires a lot of brain power.
Robin Dunbar at the University of Oxford thinks this might explain the enormous expansion of the frontal regions of the primate neocortex, particularly in the apes. Dunbar has shown there is a strong relationship between the size of primate groups, the frequency of their interactions with one another and the size of the frontal neocortex in various species.
Besides increasing in size, these frontal regions also became better connected, both within themselves, and to other parts of the brain that deal with sensory input and motor control. Such changes can even be seen in the individual neurons within these regions, which have evolved more input and output points. All of which equipped the later primates with an extraordinary ability to integrate and process the information reaching their bodies, and then control their actions based on this kind of deliberative reasoning.
Which brings us neatly to an ape that lived about 14 million years ago in Africa. It was a very smart ape but the brains of most of its descendants — orang-utans, gorillas and chimpanzees — do not appear to have changed greatly compared with the branch of its family that led to us. What made us different? It used to be thought that moving out of the forests and taking to walking on two legs lead to the expansion of our brains.
Fossil discoveries, however, show that millions of years after early hominids became bipedal, they still had small brains. We can only speculate about why their brains began to grow bigger around 2. In our forebears, this muscle was weakened by a single mutation , perhaps opening the way for the skull to expand. This mutation occurred around the same time as the first hominids with weaker jaws and bigger skulls and brains appeared Nature , vol , p Once we got smart enough to innovate and adopt smarter lifestyles, a positive feedback effect may have kicked in, leading to further brain expansion.
He thinks the development of tools to kill and butcher animals around 2 million years ago would have been essential for the expansion of the human brain, since meat is such a rich source of nutrients.
A richer diet, in turn, would have opened the door to further brain growth. Primatologist Richard Wrangham at Harvard University thinks that fire played a similar role by allowing us to get more nutrients from our food. Eating cooked food led to the shrinking of our guts, he suggests. Since gut tissue is expensive to grow and maintain, this loss would have freed up precious resources, again favouring further brain growth.
This type of feedback might have played a big role in our language skills. Once early humans started speaking, there would be strong selection for mutations that improved this ability, such as the famous FOXP2 gene, which enables the basal ganglia and the cerebellum to lay down the complex motor memories necessary for complex speech. The overall picture is one of a virtuous cycle involving our diet, culture, technology, social relationships and genes. It led to the modern human brain coming into existence in Africa by about , years ago.
Evolution never stops, though. It may be because we reached a point at which the advantages of bigger brains started to be outweighed by the dangers of giving birth to children with big heads. Or it might have been a case of diminishing returns. Our brains are pretty hungry, burning 20 per cent of our food at a rate of about 15 watts, and any further improvements would be increasingly demanding. Simon Laughlin at the University of Cambridge compares the brain to a sports car, which burns ever more fuel the faster it goes.
One way to speed up our brain, for instance, would be to evolve neurons that can fire more times per second. The 10,calorie-a-day diet of Olympic swimmer Michael Phelps would pale in comparison. Not only did the growth in the size of our brains cease around , years ago, in the past 10, to 15, years the average size of the human brain compared with our body has shrunk by 3 or 4 per cent.
Some see this as no cause for concern. Others, however, think this shrinkage is a sign of a slight decline in our general mental abilities. David Geary at the University of Missouri-Columbia, for one, believes that once complex societies developed, the less intelligent could survive on the backs of their smarter peers, whereas in the past, they would have died — or at least failed to find a mate. This decline may well be continuing. Many studies have found that the more intelligent people are, the fewer children they tend to have.
More than ever before, intellectual and economic success are not linked with having a bigger family. This evolutionary effect would result in a decline of about 0.
Crystal-ball gazing is always a risky business, and we have no way of knowing the challenges that humanity will face over the next millennia. By Catherine de Lange. WHEN I was just a newborn baby, my mother gazed down at me in her hospital bed and did something that was to permanently change the way my brain developed.
Something that would make me better at learning, multitasking and solving problems. Eventually, it might even protect my brain against the ravages of old age. Her trick? She started speaking to me in French. At the time, my mother had no idea that her actions would give me a cognitive boost. She is French and my father English, so they simply felt it made sense to raise me and my brothers as bilingual.
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