"The forehead is the doorway to the mind". This is a quotation that I will be putting on the home page of my website. Cicero was certainly very prescient when he wrote it 2,000 years ago because it's only been in the last decade or so that the functions of the frontal lobes of the brain have started to be investigated in detail. The rear part of the cortex lying behind a line running roughly from ear-tip to ear-tip deals with the processing of visual, auditory and body-sensory perceptions and was fairly fully mapped by neuroscientists during the last half-century. Very precise areas of the rear cortex dealing with very precise processing functions are now well known.

The frontal cortex -- that is, the brain tissue lying immediately behind the forehead -- has largely been a mystery. It has been known for some time that the frontal lobes have some sort of moderating effect on the rest of the brain but that was about all. Until very recently, the only evidence that was available was of a negative sort in that it came from unfortunate cases where the frontal lobes had been damaged. The classic case that's always cited in books of psychology and brain physiology is that of Phineas Gage. He was a 19th century foreman building a railway. He was using a long spike to tamp down explosive powder in some rock that they were intending to blast away when a spark ignited the powder prematurely. The force of the explosion sent the spike through his cheek bone and then through the top of his head via the frontal lobes.

This inch-wide hole burrowing right through his brain didn't kill him, or even affect his sight, hearing or the fine control of his bodily skills -- as it certainly would have done if the spike had gone through the rear part of his cortex. However, when Phineas Gage had recovered from the superficial damage of the injury, and to everyone's surprise. he appeared to be unaffected as regards his physical abilities as he walked about or spoke to them. He could even do his previous work. But his personality had changed considerably. He had become a different person altogether. Previously, he had been a reliable, courteous and responsible person he had now turned into someone who was extremely unreliable, irresponsible and given to aggressive outbursts. He was, in fact, impossible to work with and he soon drifted away from the railway works and thence out of ordinary society altogether.

The function of the frontal lobes of the cortex appears to be that of a provisional holding centre before actual behaviour takes place. It has the capacity to delay any sort of utterance or physical behaviour which might have serious consequences. It's also involved when novl perceptions or unsuual problems are involved. For most everyday purposes, the frontal lobes exercise only a slight delay to our intended behaviour. For example, when driving a car along a well-known route, the physical movements made in controlling the car will take place within about half a second of the relevant visual signals coming into the rear cortex -- such as after seeing the roadside trees preceding a steep bend in the road, or the colour of the traffic lights at a busy cross-roads. However, if something unusual happens along the route, such as a tree having fallen across the road or a traffic light which wasn't working, then the frontal lobes will take over instant control and will delay any response for at least another half-second while it is considering exactly what to do even though, in reality, it is an emergency situation.

It's only been in recent years that various techniques such as positron emission tomography (PET scans) have been able to examine the frontal lobes non-invasively -- by scanning the brain from outside the skull in order to search for busy activity. These show very clearly that when habitual actions are being expressed -- no matter how skilful they may be -- they are being controlled by the rear cortex and the frontal lobes are hardly involved at all. They are pretty quiescent. However, if there is the slightest degree of novelty in the situation then the frontal lobes come into action straightaway. I remember a performance of Haydn's great 'Cello Concerto in D when the soloist's 'cello string snapped like the sound of a gun! There must have been a slight pause of half a second or so (I cannot remember precisely because it was 40 years ago!) and a note or two was probably lost, but the cellist immediately moved his hand onto the next lower string and carried on playing in a higher -- and far more difficult -- position until the end of the movement when the orchestra could pause and the string was replaced. The 'cellist's frontal lobes would certainly have been involved on that occasion! Whereas, up until that catastrophic moment, his playing would have been mostly under automatic control from his rear cortex -- his having played it scores, if not hundreds of times previously -- his frontal cortex was now having to deal with a novel situation. And it would have been not only devising novel finger movements that he had probably never played before, but he was having to anticipate particularly difficult phrases that were lying ahead.

The frontal lobes deal with novelty, can invent new procedures and be creative, and can anticipate alternative future scenarios. It can also modify extreme emotions, particularly those which might endanger the individual. And, as emotions are usually expressed towards other individuals rather than inanimate objects (though these can often be substitutes chosen by the frontal lobes!) then the frontal lobes are the great socialisers of the brain. The frontal lobes can't neutralise strong genetically-based emotions but it can often steer them into safe directions. It is the frontal lobes that can (on occasions) cause you to count to ten before replying in anger; meanwhile, with luck, the adrenalin flow has died back somewhat.

In the case of our species, the frontal lobes are very sizeable when compared with other primate species that are still living on earth. It is this which makes all the difference in the tactics of a male who wants to become the boss of any group. A baboon, with little by way of frontal lobe tissue will almost always act aggressively. A chimpanzee has larger frontal lobes and can be a little more devious or more sophisticated in the way he goes about it, even to the extent of being able to form temporary alliances with others in order to overthrow the alpha male.

An observation of an amusing way a chimpanzee assumed alpha status was once made by Jane Goodall. One low-ranking chimpanzee found an empty petrol can and started banging it with a stick. He immediately caused consternation and terror in the chimps around him, and even the alpha male and his lieutenants made signs of submissiveness to him. For a few days, he had the pick of the best food and the most comely females were available to him. However, he lost his petrol can a few days later and, immediately, he lost his top ranking, too! If this chimp had possessed a little more frontal cortex he might have realised that, even if he couldn't find his petrol can, he could probably devise some other similar method of making loud noises and resuming his alpha role. But he hadn't and he didn't. He resumed his place at the bottom of the heap as regards being offered choice pieces of piglet that the group had hunted or sexual favours from the best females.

But early hominids with much more frontal lobe tissue -- as we can deduce from the shape of their fossilised skulls -- would probably have made this sort of creative connection. By the time homo sapiens appeared, the male of the species was probably up to all sorts of creative tricks in order to make himself more important and cleverer than the others in order to attract the best females. He was probably making the well-known statuettes as presents to the ladies or bone flutes to play to them. One of those tricks would undoubtedly have been bodily ornamentation, either of permanent tattoos (as on the recently discovered preserved body of Oetzi, the Austrian iceman, of 3,000BC) or of temporary pigments, feathers or bangles. The male of the species is such an exhibitionistic role player that, in all hunter-gatherer societies yet observed by anthropologists, the males carry out some form of bodily ornamentation. In some of the few tribes that still remain there are even special ceremonies in which the young males, wearing dresses and facial make-up, stand in line (or dance or sing) from which the girls choose their partners.

All this, without any doubt, is a product of the creative ability our frontal lobes and the ability to steer status-seeking away from dangerous physical fights, as with baboons and chimpanzees. As with personal anger and other social behaviour, the frontal lobes can't neutralise the deeper instincts and emotions of status-ranking -- this is present in all social mammals and particularly so in the primates -- but can certainly modify them. The large frontal lobes of our species are well able to create highly imaginative displays. It is therefore no surprise that, even from times of 75,000 years ago, not long after the beginnings of homo sapiens, there is evidence in cave dwellings that man was using strongly coloured pigments that had come from original sites a hundred miles or more away. They must have been so highly valued that trade routes had actually developed by means of successive barterings at tribal boundaries. There was no way that individual hunter-gatherers, or small groups of them, could have travelled such large distances through unkbown, physically dangerous and potentially hostile territories. It might be asked "Why, if adjacent territories were hostile, did they trade?" The fact is, though, that they did. In most hunter-gatherer tribes ever observed, sons or daughters are traded in some way across territorial boundaries even though the tribes might be at each others' throats most of the time. In the recent wars in Serbia between Muslims and Serbs, foir example, the antagonists would frequently stop their murderous fighting in order to set up market stalls and do some trading for food and other necessities. And then back to fighting the next day.

The use of ochres for use in cave paintings as evidence of some form of religious rites has been highly overstated. There is no evidence of extra preparation around these drawings by way of special settings, or ceremoniues, or altar-like constructions. Although cave paintings are often brilliantly done, showing that man's artistic abilities were just as great in his earlier days as he's ever been since, everything about the cave paintings of Lascaux and elsewhere suggests a casual origin -- often additional ghostly hand imprints appear over them or stick men inapporpriately added to the flanks of a rhinocerus, and so on. They were probably drawn ad hoc to memorise a successful or dangerous hunt, or to teach hunting strategies to the young males.

However, as more fossil evidence accumulates from man's earliest times, perhaps from the discovery of non-cave sites in which ochres will be found, then it will be increasingly realised that the first, and most valuable product ever traded by man was almost certainly coloured ochres and pigments that were used for personal display in order to establish rank order and sexual choice by the females. Then, as know, females are generally attracted to males of higher rank and intelligence than themselves because the former offer more economic security for the sake of raising the children, whether this is the hunting skills of former times or a high-salaried job today.

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The size of the brain and the frontal lobes in particular grew at an extraordinarily rapid rate in the millions of years before man appeared. The general brain size was growing pari passu with body size so there was nothing remarkable about that. But the mutation rate which produced the large frontal lobes is a different story. Of course, the enlargement of the frontal lobes per se is understandable because it would have conferred extra survival benefits to those males who had more than the usual amount. His offspring would have survived preferentially and the trait would have been passed on. However, the rate at which the frontal lobes expanded suggest that what biologists call "runaway" or sexual selection took place additionally to normal Darwinian selection.

The peacock's tail or the outlandish size of the reindeer's horns are of no survival use. In fact, they are probably a disadvantage because extra energy and nourishment is needed in order to grow and maintain them in good condition. But what these extra accoutrements also meant was that the male with an outstandingly large version of them would also have to be outstandingly fit and strong. In an unconscious way, the females, when considering which male should be allowed to sire her offspring, therefore took to preferring the peacocks with the biggest and most efflorescent tails, or the deer with larger horns and perhaps additional branching. Some biologists therefore think that it is quite possible, therefore, that human females tended to give their sexual favours to males who had a more vertical forehead than their peers. The females didn't need to know this consciously. It would just so happen that their offspring survived a little better. The gene which caused the male adornments to grow and the female preference for them would concentrate this trait within a population. It is speculative whether this sort of additional sexual selection took place, but either way, a population in which females chose males with a more vertical forehead (who also was able to devise clever status signals) rather than those with raked-back foreheads, would be choosing a more creative and intelligent partner and her children would benefit accordingly.