Why (some) brains like to jump off cliffs.
Or: A brief look at the Neuroscience of Extreme Sports.
Howick Falls, South Africa. It’s one of the prettier spots on this planet, a 310 feet waterfall surrounded by cliffs, which makes it an often frequented tourist destination. One day in February 1999, a chap called Jeb Corliss had slightly different plans. This day was a day that, as he later stated, would have “changed him as a person”. The common Howick Falls tourist enjoys just looking at the majestic cliffs; Jeb prefers to jump off them. He is a professional B.A.S.E. jumper, meaning that he parachutes from fixed objects, rather than planes or helicopters.
He failed to adequately deploy his parachute and ended up being sucked into the waterfall rather than landing next to it. The water’s mighty forces released him about an hour or so later, only after breaking Jeb’s left foot, right knee, and most of his ribs.
Now, a mere 15 years later, the world mostly knows Mr. Corliss as The Daredevil; he has become a celebrity in the sport of proximity flying, which combines jumping off cliffs with an even more dangerous part — racing past the surrounding mountains as closely as possible at speeds of up to 130mp/h, sometimes clearing these only by inches (if all goes well).
Has he, “as a person”, changed?
There are sensation seekers like Jeb Corliss, who are taking tremendous risks for the sake of pure sensation.
And then there are risk takers (such as the infamous Isaac Newton who once stuck a needle in his eye to scientifically examine the resulting visual artefacts), where risks are taken to obtain a certain outcome.
Which of these two sound more sensible to you?
Sensation seeking has usually been scientifically described as the likeliness of an individual to take part in, as well as enjoy, activities with higher degrees of risk without an obvious return besides self-realisation (sorry for the dry definition, it is needed!). Looking at a definition like this, sensation seeking behaviour seems quite stupid.
In our society however, sensation seeking behaviours become increasingly more aspiring, if not attractive; they are, as the BBC puts it, “surfing to success”.
Was this always the case?
During the 1930s, sensation-seeking behaviours were generally described psychological pathologies. They were described as the display of a death wish in the psychoanalytical literature; Anne Freud, Sigmund Freud’s youngest daughter, called it a “fear of masculine inadequacy” or “fear of castration”.
As with most psychoanalytical theories, no research has been carried out to support this notion (how would you anyway?).
The Cognitive Revolution (which describes the move away from purely observing behaviours towards attempting to experimentally understand some of the brain’s workings) in the 1950s also brought a change to how society viewed sensation seeking behaviours; pretty much all of a sudden, they were considered healthy and even natural. The researcher Clarence Leuba hypothesised in 1955 that (1) a lack of stimulation leads to boredom, and (2) an overstimulation leads to stress and loss of control; individuals function best if they keep stimulation within that fine balance (or: if we find a level of stimulation that is optimal — for us). What this level of optimal stimulation is varies from individual to individual; also, we might be risky only in some areas of our lives, not all of them (some might be more prone to risk their wealth, rather than their health).
But what is happening in our brains (and their attached corpses)?
What is the biological basis of brains aiming to put themselves into extraordinary danger?
We can start this with a simple question; how do we measure the risk of situation? A group of Parisienne and Welsh researchers showed that the ability to understand and regulate one’s own emotions is important. Most research efforts have then focussed on neurotransmitters, the chemical substances that transmit signals from one nerve to another.
Nerve cells are not directly connected to each other.; therefore signals are transmitted by releasing these neurotransmitters into the area between nerve cells (the synaptic cleft) which are taken up by the receiving neuron and converted into another (electrical) signal. This is what we mean by synapses.
Sensation-seeking behaviours are most likely influenced by the neurotransmitter Dopamine, which is involved in many aspects of cognition as well as mediating the feeling of reward (and is therefore also dubbed the “Neurotransmitter of Addiction”).
In order for dopamine (that was released by a neuron) to convey a signal, it requires receptors in the receiving neuron that react to its presence in the synaptic cleft. There are some categories of receptors, most of which are create a signal in the receiving neuron. Then there are special cases of receptors that are called autoreceptors; these monitor how much dopamine has been released into the synaptic cleft. As they have the power to stop dopamine production, they act as a control instance or negative feedback loop. In case of dopamine, these are called the D2 & D3 autoreceptors (bear with me, this is the dry scientific part — but it’ll all be needed later on!)
How can we understand a daredevil like Jeb Corliss by looking at brain cells?
Albert Gjedde from the University of Copenhagen correlated the tendency sensation-seeking behaviours to the occurrence and distribution of these dopaminergic receptors. He turned to a specific brain area — the striatum, which has a major role in many higher-order functions such as associative learning and decision making. As any skilled neuroscientist does, Mr. Gjedde first sliced up rat brains. After these first studies, he hypothesised that the higher a subject’s tendency to indulge in risky activities is , the fewer D2 and D3 auto-receptors are present. Unlike most neuroscientific studies, Mr. Gjedde was lucky enough to find results just as hypothesised, with a data set that “came out essentially perfect”, as he later stated.
So far, so good, but why can this have such a widespread effect? A fewer number of autoreceptors simply means that the dopamine production is less likely to stop even if it is already saturated, hence an overproduction is more likely to occur. It is also relevant to note that this process is especially important under extreme conditions, as autoreceptors limit the maximum signal strength a neuron can elicit.
Sensation seekers are so prone to seek out extreme activities as it allows them to fully leverage their potential of maximally “flooding” their brain of dopamine, which, after all, is the neurotransmitter of reward and pleasure.
So where does this leave us? The above-mentioned studies provide an interesting window into the world of how examining biological mechanisms can enrich our understanding of day-to-day human behaviour. It is important, however, to understand the limitations of these insights as well — all of these are hypotheses rather than indisputable facts. And also note, before you go out and do the first reckless thing you can think of; it is quite likely that you are part of the vast majority of people who wouldn’t.
This text was originally produced as part of a B.Sc. Cognitive Neuroscience degree at the University of Westminster; it was submitted for review on the 12th March 2014. I’ve edited it for Medium in November 2014.
