Nature Climate Change: Carbon fix

Nature Climate Change 3, 765 (2013) doi:10.1038/nclimate1998

Published online 28 August 2013

Lessons from addiction may help to transform our high-carbon lifestyle.

It is often said that those of us who live in affluent, developed countries are ‘addicted’ to our high-carbon lifestyles, which depend on profligate use of energy and material resources. Think of central heating, air conditioning, our reluctance to wean ourselves off international air travel — whether for business or pleasure — and the amount of meat that we consume in our diets.

Our love affair with the petrol engine is a case in point. In their advertisements, automobile manufacturers often still portray models of cars as outward symbols of male potency, power and career success, or — especially for brands targeted at young women — a penchant for fun and glamour. This is all reminiscent of the way that cigarette brands were once marketed — and to some extent, shamefully, still are in parts of the developing world. Parallels could also be drawn between the way that, in these days of environmental awareness, motor manufacturers increasingly emphasize ‘green credentials’ such as fuel-efficient engines, with the way that the tobacco industry tried to shift attention to low-tar brands when the evidence that smoking causes lung and other cancers became unassailable.

But it would stretch credulity to push the comparison too far; obviously cars are not ‘habit forming’ in the sense that cigarettes are, and certainly do not have the addictive characteristics of certain hard drugs. The habit-forming effects of drugs such as nicotine and heroin are mediated by specific receptors in the brain. But it is of course meaningless to talk of a specific ‘brain receptor’ activated by exposure to a car advert. Nevertheless, it is reasonable to posit that our responses to brands in general, the preferences we develop and the behaviours that we subsequently exhibit as consumers (and more generally as citizens), have a neurobiological basis. This does not at all imply that such preferences and behaviours are deterministically ‘fixed’, in the sense that they can be modified by learning and experience, or even pharmacologically. If we are sufficiently concerned about the environmental impact of travel, we can by our own volition choose to run an electric car rather than a gas-guzzler.

This seems to be a starting premise of the intriguing new research field of ‘neuroconservation’, which despite its name has nothing to do with conserving neurons. Rather, as explained by Elisabeth Jeffries (see below), one of its aims is to study how the brain responds to nature. A working hypothesis is that the way we come to value and appreciate the natural world may involve some of the same brain regions and ‘reward’ pathways involved in addiction. If that turns out to be the case, which is far from certain, it follows that understanding addiction — both at a neurological and psychological level — might potentially help to devise strategies for shifting people’s attitudes in relation to environmental issues such as climate change, thereby promoting climate-friendly behaviours.

Excerpt from the paper by Jeffries published in Nature Climate Change:

To gather momentum for the campaign and to help develop the new field, dubbed neuroconservation, Nichols draws neuroscientists with a range of specializations from across the world. It is an embryonic field, which has hardly defined its own terms of reference yet. As Nichols puts it: “Our priorities are skewed, and not much has been done. What I’m trying to do is collect the dots from research on other things surrounding the questions we need to ask that are useful to our subject”. Potential research themes have ranged from the psychological reasons for the limited fish varieties eaten in the USA, to the use of surfing to help war veterans recovering from physical and psychological injuries. Curiously, many of the scientists gathered together by Nichols are from the field of addiction treatment.

Or perhaps that is not so curious. One of the objectives of the project is to draw our attention to the beauty of the ocean and the natural world, and to assess its neurological benefits. It follows, therefore, that knowledge about addictions that keep us away from nature is likely to be very useful. David Zald, Associate Professor of Psychology and Psychiatry at Vanderbilt University, Nashville, USA, has studied the relationship between the two.

The mechanism that he has investigated is the mind’s capacity for temporal discounting (pleasure definitions, and reward and motivation mechanisms are others), the ability to overcome an immediate impulse in exchange for a later, bigger reward. The relevance to neuroconservation is clear. Experience shows that if people can wean themselves off the self-centred activities of alcohol, drug, tobacco or food addiction they are more likely to seek rewards from more wholesome behaviour instead.

Zald notes that temporal discounting is an important component in the development and maintenance of drug addiction. Addicts have high temporal discounting, which means they rapidly discount the value of rewards further in the distance. Researchers have identified two competing neural systems related to temporal discounting using brain imaging techniques1. They find that choices for delayed outcomes are related to the brain’s prefrontal cortex (the executive system) whereas those for immediate outcomes are related to the limbic brain regions (that is, the impulsive system).

Animal and human imaging studies have revealed discrete circuits that mediate the three stages of the addiction cycle in the brain. Key elements involved include the ventral tegmental area (a group of neurons in the midbrain) as a focal point for the binge/intoxication stage, the extended amygdala (almond-shaped groups of nuclei in the medial temporal lobes that process memory and emotional reactions) in the withdrawal/negative affect stage and a wide network of various other elements in the preoccupation/anticipation phase. Transition to addiction involves neuroplasticity in all of these structures, eventually leading to dysregulation of various parts of the brain2.

“We believe that the prefrontal cortex [the very front of the brain] exerts inhibitory control that allows you to remember the long-term objective and inhibit immediate urges. Drugs reduce that power and promote immediate urges through their action on what is called the reward pathway,” says Howard Fields, director of the Wheeler Centre for the Neurobiology of Addiction at the University of California, San Francisco. Fields has also considered addiction in relation to potential neuroconservation research.

Identifying the addiction process in the brain has helped to suggest ways to interfere with the addiction (possibly using pharmaceuticals) and test improved prevention and treatment programmes. This is because addiction relapse often occurs after a year, even when cognitive therapy has been used. “Using this kind of research, we can combine cognitive approaches with medical approaches. You train people to develop new incentives that will devalue the effect of, say, alcohol,” explains Fields.

According to experts, addicts code and prioritize rewards. “In addiction the drug or rewarded activity is ‘locked in’ as a stronger incentive than other potential rewards. In such a situation it is hard to find rewards that exceed the impact of taking the drug or engaging in the behaviour. The punishment has to be great. Alternatively, the person has to be able to identify a stronger reward, or some combination of reward and penalty, to overcome the compulsion to seek or engage in the addictive behaviour,” says Zald.

But he says neuroscientists still need to answer numerous questions to help addicts further. They know addicts have low temporal discounting, but are unsure of the predictive usefulness of this information. “Does temporal discounting actually predict risk for drug use initiation, does it provide a strong prediction of risk for relapse, does knowledge of temporal discounting have value in predicting what type of therapy is most likely to work for an addict?” asks Zald.

Fields believes that two main issues need to be resolved. “How and where in the brain do the drugs act to produce their ‘virtual benefit’ where the brain changes that encode benefit are activated, like they would be if you were hungry and had a meal. How and where in the brain do the drugs act to produce drug dependence?” Meanwhile, Zald suggests that the evidence they may find most useful is the behavioural or biological (neuroimaging/genetic) information that can be used to predict treatment success.

The parallels between holding back on another whisky or switching off a smartphone are clear, but could the research on temporal discounting in alcohol or drug dependency be usefully transposed to conservation? Zald thinks it could: “There are clear predictions that can be made from the [studies] that are likely to apply when looking at conservation. These seem like safe predictions, but they really warrant testing,” he says. Conversely, Fields indicates that he is “not confident it’s the same system. It’s a hypothesis.”

“I would start by having people make decisions about exploiting versus taking actions to protect the ocean. I would then start looking at ways of altering decisions. To me the most critical thing is can we predict actual changes in behaviour — either short-term or more importantly long-term. Do we predict them better based on people’s immediate self-report, or based on brain imaging data?” he says. Certainly, it is difficult to see any drug trials against consumer addictions emerging any day soon to awaken our concern for nature. Instead, two potential routes are likely to emerge for neuroconservation research. One is aimed at behaviour change, and the other a medical approach focused on demonstrating the benefits of the natural world on patients. Envisaging a possible research programme, Zald suggests a behavioural approach, beginning with the development of techniques that moderate temporal discounting:

However, previous cases show that hospitals are likely to provide the first avenue for neuroconservation research. Responses to nature have already been investigated in medical research. For example, the benefits of hospital beds that face green spaces are well established. One study showed that medication dispensed by nurses in a psychiatric ward was significantly lower on days when a realistic image of a landscape was displayed3. Another, conducted by South Korean medical institutions, used functional magnetic resonance imaging to explore the brain activation maps from participants viewing two different types of scenery (rural and urban)4. Their findings suggested an inherent preference for nature-friendly living.

At the Peninsula College of Medicine at Exeter University, UK, psychologists demonstrated that good health is more prevalent the closer one lives to the coast5. They also indicated that the positive effects of being close to the coast may be greater among more socio-economically deprived communities. Matt White, one of the authors, explains: “our research can be used to quantify the relative marginal gain extracted from nature [in terms of quality-adjusted life years] and how that measures up against drugs”.

Wallace J. Nichols plans to launch neuroconservation as a research field in 2014. New studies using neuroscientific techniques are likely to come from Exeter University and Stanford University (USA). “The question we want to answer is to what extent you can bottle nature and bring it to medical and care environments,” says White. For example, could the sound of crashing waves benefit patients? The question has never been explored or scientifically measured.

Public health data sets have already been used as weapons against brands in rows between corporate responsibility campaigners and brand owners about obesity. But after years of disputes, it is evident which party has the bigger clout and budget. Medical research provides only a narrow channel for this kind of social question, which has much broader implications. Hence, its impacts could be limited.

Scientists aiming to cut a new track in this area will have to contend with claims of bias. There are, after all, several obvious assumptions behind their research. That is as true for some of the subjects of the experiments as it is for the principles that motivate the research itself. “People don’t understand how we develop a system of values. Peer pressure can promote or suppress the use of drugs and is an important factor in tackling addiction. We don’t have a theory broadly agreed, though, on how people develop reward systems. That’s why we can’t be confident observing attitudes to nature is based on the same principles as attitudes to drugs” states Fields.

Meanwhile, if we do not understand how values are created, the research itself, which implies certain value judgements, could be construed as unsound science. Conservation is a heavily loaded term, suggesting a particular political viewpoint. That means some of the questions hypothesized by scientists could be attacked, and some of the truth ethic behind the research compromised.