We have looked at altruism, in the sense of ‘altruism with a purpose' as a sub-conscious strategy (in a nice way) for maximising the returns which can be obtained from being a part of society or of a group of some sort. Altruism, though, works mainly on a medium-term basis - we do not normally expect an immediate return for our ‘altruistic' actions, but neither do we expect to wait for ever.

So then what about long-term decisions? How do we weigh up longer term advantage against short-term gain? After all, we are able to anticipate the long-term consequences of our actions and, with the relative stability of our society and longer life spans, the long-term takes on an ever-increasing relevance to our lives.

But although it may be the ‘rational' way forward, even looking ahead a few months to the exams at the end of a degree course can seem like an eternity when the pub and your mates beckon. Likewise, the struggle to give up fags must be very difficult when comparing the lure of just one more, as against the possibility (although not certainty) of illness in twenty years time. When thinking about pensions, it is difficult to envisage being 60 when you are only 20 and it is even more difficult to believe that the 40 years will pass as quickly as they do.

So then why is it so difficult to act rationally? Well, the clue is in the question. It is commonly assumed that in the ideal world we should try to act more rationally and less emotionally, but that we fail to do this because of our weakness of will. What is ignored is that the emotionless Mr Spock from Star Trek would be a very poor role-model. It has long been reported in connection with people who have brain damage that if our emotions are not engaged, then we will do nothing - a Mr Spock, with all his logic would do absolutely nothing unless he had an aim he wanted to achieve. It is our emotions and drives which give us our aims and not our reason or some separate ‘will'.

After all, a ‘will' cannot be separate - if it existed it would have to be a part of the physical us and therefore either it would be affected by what was going on around and within us or it would be some random decision generator, for which there is ample evidence to the contrary. The concept of a separate will simply has no meaning. And reason itself merely enables us to foresee the likely outcome of the options before us and in so doing assists us to achieve more efficiently the end our emotions and instincts persuade us to pursue. Using reason without emotion is like having a map, but not wanting to go anywhere!

Until very recently, in evolutionary terms, our aims were directed at keeping us alive on a day to day basis. We had the immediate need to get food, avoid being eaten by wild animals or killed by members of other tribes. Long term pension provision was not on the menu.

But it is essentially the same brain that is being used to make decisions for our times. Its mix of emotions and drives and the weight they each have, have had very little time in evolutionary terms to change significantly since those simpler days when short to medium-term action was all there was and our drives and emotions were fine-tuned accordingly. It is perhaps not surprising, therefore, that we feel a bit at sea when we are faced with decisions to do things which will only affect some seemingly remote future and, sometimes then, only in an uncertain way.

But if we know that it's our emotions that we have to influence, and not overcome a weakness of intellect or of will, we can increase the likelihood of acting in our long-term interests if we can make the result of so acting more real in the present. To do this, we have to look into the future and, by doing so, ‘feel' the effect now of the various possible courses of actions which we might take. The more detail in which we think about possible outcomes, the more real they will seem and the more they will engage our emotions, amplifying our wish to achieve or avoid those consequences. It is rather like the way athletes are encouraged to imagine each step of the race in order to make it real to them in advance.

I am afraid though that the human mind has not yet really evolved in a way which enables us to have deep within us a different balance of aims directed more at the long term. Maybe the balance of our emotions will change over the coming millennia in response to evolutionary pressure in order to give more weight to what might happen in the distant future. It's early days yet for the human race. Maybe Captain James T Kirk of the Starship ‘Enterprise' will indeed find it easier to weigh things differently.