Thankfully, most of us don’t keep plumping for the same option in life, over and over, regardless of how rewarding it might seem to be. No, we take into account what might have happened if we’d taken a different path, made a different decision. These so-called ‘fictive’ thoughts can lead us to change the way we behave in the future. But now Pearl Chiu and colleagues have shown this ability is lacking in smokers – a finding they say could have implications for treating addiction.
Thirty-one smokers and 31 non-smokers had their brains scanned as they played an investment game. They were given $100 with which to invest in stocks and shares and after each round they were told how much money they’d made, relative to how much money they could have made if they’d invested the maximum amount in their chosen shares.
Discovering how much money they could have made if they’d invested a larger amount affected the subsequent decision-making of the non-smokers but not the smokers. It’s not that the brains of the smokers didn’t register this information – they, like the non-smokers, showed increased activity in a part of the brain called the caudate when shown what they’d missed – it’s just they didn’t act on it. Pearl Chiu and co-workers say this cognitive anomaly helps explain why smokers carry on puffing away without regard for the positive outcomes that could have ensued had they have given up.
Co-author Read Montague told The Digest: “It’s not at all clear from our work yet whether subjects who end up smoking (chronically) start out with a weak coupling between fictive error systems and behavioural control or whether this connection weakens as they become addicted to nicotine. We are gearing up to do a longitudinal study to find this out.”
Chiu, P.H., Lohrenz, T.M., Montague, P.R. (2008). Smokers’ brains compute, but ignore, a fictive error signal in a sequential investment task. Nature Neuroscience DOI: 10.1038/nn2067