Those close to Gordon Brown pushed as many bananas into him as they could. I expect this was because bananas are supposed to increase serotonin, which in turn should help calmness because serotonin is considered the ‘happiness’ neurotransmitter.
But it isn’t. Yes, it really can be considered a mood neurotransmitter, just as noradrenalin is associated with excitement, and dopamine is linked to goal-pursung activity. However, the nuts and bolts of the brain don’t always exactly match our concepts of mind perfectly; and because our established concepts are so strongly established and the related brain entities are so slightly different, those differences are hard to get our minds round. The first hint that serotonin secretion does not quite equate to happiness comes from the intriguing way it’s linked to violence, and which suggests it’s used more as an ‘It’s OK’ transmitter. Which is subtly different from ‘I’m happy’.
People with high serotonin sometimes showed antisocial behaviour more often on average – which seems odd if we’re linking serotonin to happiness. An extra complication might clarify the picture: those maltreated in childhood were the ones showing the violent behaviour. But oddly, the high serotonin people generally showed less antisocial behaviour than normal! – so long as they hadn’t been maltreated in childhood.
If you model mind and behaviour you soon notice that current behaviour has to be reconsidered moment by moment. ‘What to do next?’ is and needs to be a major preoccupation. When things are going badly, stop doing what you’re doing, and start doing something else. (God – if only those with responsibility understood this more! National sporting governing bodies and influential scientists come first to mind.) Anyway, pain, punishment and disappointment bring changes of (or repression of) behaviour, but pleasure encourages continuance… and that’s were serotonin might fit in.
If its role is to tell all parts of the brain “It’s ok to carry on doing what we’re doing”, that might apply if we were brought up pleasantly and had developed strong habits of contentment. Serotonin then would say “It’s ok to keep on being nice and happy”. But if anger had been linked to from frequent situations springing from maltreatment in the past, high serotonin would now say “It’s ok to carry on breaking things off and hitting people with them.”
Although high serotonin was, in the Dunedin study mentioned above, sometimes related to negativity, low serotonin is of course classically associated with negative moods and behaviours. That’s why Prozac is employed: to increase serotonin and hopefully the rest will follow. A better solution, if it could be done, would be to increase serotonin when people were relatively, happy but decrease it when they weren’t.
So my advice would be to stop pushing bananas into people if they’re already cross.
Do the body and mind categorise and organise?
Why should the body have “moods” or ready-made patterns of behaviour apparently mediated by age-old neurotransmitters? Moods which we presumably shared with ancestors and relatives that we might not even be able to share legs with! Presumably it’s a game theory thing: sometimes certain formulas of behaviour are always going to be optimal. It’s also going to be worthwhile preparing the body for these patterns of action, just as the mind is separately readying the characteristic behaviours.
A related question is why does the body so often organise itself into organs or other modules? Why, for example are all the endocrine glands not combined into one big one tasked with all the hormones-etc-into-blood duties at once? Couldn’t individual cells have been assigned to the particular duties whole organs actually do?
Clearly not, or at least not optimally. This means I think that we can talk of particular organs being genuinely considered by the body for something in particular, and embryological development (so often involving switching on and off of modules) being the process of preparing certain functionalities, no matter how implemented.
And we are right to associate certain concepts such as moods, to certain patterns of brain/mind behaviour. But we must be very careful to get these right. As we’ve seen, ‘being happy’ might be consistent with showing signs of anger, if our definition of happy is wrong. Sometimes a mental entity might equate to increasing something, but the entity might not apply once that something were achieved: not magnitude but rate of change.
Then again, the reality night just be hugely more complicated. Dopamine has all those problems I’ve hinted at but its picture is also hugely more complex. Dopamine isn’t any one thing: it has several different receptors, some excitatory, some inhibitory – and those different receptors might be genuinely considered subdivisions of their transmitter’s overall task. Dopamine is like the electricity that powers a multiprogrammable computer. It does different things in different places, and those separate things can be meaningfully summed up as a concept, and which may well be simple, but which are different from the concepts currently used by our generation.
Another thing. These neurotransmitters turn up elsewhere; the digestive system for example incorporates opiates as well as serotonin. Could their current usage in the brain be grossly sophisticated developments of their more primitive actions? Yes, often; and probably usually. Possibly always. Dopamine is secreted by various neurons with cell bodies in various organelles of the brain, but the evolutionarily earliest is presumably the one furthest back down towards the brainstem: the substantia nigra. It’s called nigra because it contains melanin! Why should such an epidermal molecule be buried so deep? And what is the significance of the detrimental effect on the establishment of certain visual pathways of lack of melanin in certain albinos? There’s even more meat in that set of mysteries than the simple wonder of dopamine-mediated bodily action production circuits apparently being incorporated into the long-term planning system.