Currently in the UK we have the very interesting situation of two brothers - David and Edward Miliband - vying to become leader of the new labour party and fill the shoes vacated by Gordon Brown, the former Prime Minister.
The two brothers are currently the bookies' favourites and no matter the outcome, Christmas Day in the Miliband household has to be an interesting affair both before and after the votes have been counted.
For obvious reasons, their mother says that this is one vote she will definitely be abstaining from!
On the very day of posting this article (June, 1, 2010), it became even more relevant as 'quiet, family man' Derrick Bird shot first his twin brother and then the family solicitor over what was believed to have been a bitter feud over a will. He then went on to massacre 9 more people and injure dozens more in the rural countryside of Cumbria, UK.
Which all serves to illustrate the nature of the deep and powerful emotions these sibling relationships can arouse in us and that many have been throughout history - and continue to be - stirred to murderous rage when these relationships turn sour.
So what effects do sibling relationships have on our lives?
Four out of every five of us have at least one sibling and one-third of those relationships are said to be distant or strained in adulthood. From bickering and squabbling, through severe psychological and physical scarring and open hostilities to murder, navigating the terrain of some of the most enduring relationships of our lives can prove problematic - or immensely rewarding.
Sibling rivalry in literature
The theme of sibling rivalry has been well explored in literature going back to the biblical story of Cain and Abel where sibling rivalry over the appearance of favouritism by God leads to fratricide as Cain murders Abel.
Shakespeare too, explored the subject in many of his plays and many modern day script writers have created rivalrous sibling relationships as in the creation of Bart and Lisa Simpson of The Simpsons, Ross and Monica Geller in Friends, Frasier and Niles Crane in Frasier and Michael and Fredo Corleone in The Godfather.
In life, sibling rivalries - some seemingly conducted with slightly more civility than others - include the tennis players Venus and Serena Williams, musicians Liam and Noel Gallagher of Oasis and the singers and performers, the late Michael and Janet Jackson.
Sibling rivalry in nature
Nature can be ruthless in 'naturally selecting' out the weak or the slow with siblicide common in some species. The biggest baby shark, for example, starts as it means to go on and eats its siblings in the womb. The first eaglet to hatch too pushes its younger siblings out of the nest to their death in order to ensure that they alone secure 100% of the available resources.
Even when your siblings don't actually eat you or ensure that you die, competition for resources in nature is fierce and being favoured by a parent can mean survival and being less demanding, less strong or just small can see you perish prematurely.
Whilst siblings have some biological investment in their brothers and sisters surviving in order to preserve their familial genetic line, ultimately the only individual with 100% of your genetic makeup is you - or an identical twin. So, on the 'selfish gene' basis of life, preserving your own genetic line ranks as more important than aiding your siblings to survive.
In the human family children are competing not so much for survival but more for the scarce resources of parental time, attention, love and approval. Children all over the world are incredibly sensitive to any intimations of preference by one or both parents including being favoured with a slightly bigger helping of food or drink!
The origins of sibling rivalry
Imagine, if you will, that you have been on the receiving end of 100% of your partner's attention and that you have enjoyed a loving, intimate, special and above all, exclusive relationship. Now imagine that they bring home another extremely high maintenance partner with whom they and everyone else seems very enamoured. The arrival of this interloper means that your share of love and attention immediately drops to somewhere around the 30% mark. And frankly, even when you do garner some attention, your partner seems tired, irritated or preoccupied since the new arrival came on the scene.
How pleased would you be?
Now imagine that you have been an only child basking in the love of both your parents. You are experiencing powerful emotions - many for the first time, but you may not yet be able to talk and you haven't yet acquired the ability to reason the situation through.
You almost certainly don't welcome this turn of events and your feelings of dislike can be readily transferred onto the intruder. From the age of about 18 months children broadly understand social rules and can choose to either comfort or hurt their siblings, and by 3 years of age they can compare themselves to their sibling and devise strategies to win parental attention.
The extent to which sibling rivalry is experienced can be more or less intense depending upon factors such as the relative genders of the siblings; the age gap; their personalities; their talents and gifts; their respective size and appearance and whether one or both parents identify with or favour the child.
If the second child's gender is different from that of the oldest child, then the rivalry experienced may be diminished as a result of both children automatically having a 'special' status within the family as the only daughter or son. With same sex children, Sigmund Freud considered that brothers were in competition for their mother’s attention and love and sisters competed for their father’s favours. As you see, the root causes of these problems are the timeless and universal circumstances shared by all human families.
The fact is that in spite of coming from the same 'stable', you and your siblings often have completely different experiences of life because of the timing of house moves, the different stages of your parent's lives, age differences, attending different schools, being different genders, physical size and appearance and being different personalities with different abilities and talents.
It is also considered important that the parents prioritise spending time alone with each of their children, which frankly does not happen unless you engineer it. The author and motivational speaker, Stephen Covey, describes taking one of his nine children out for breakfast each weekend which was something they appreciated into adulthood.
The answer to the question "Why do children fight so much?" is because they can test the limits of the relationship and, unlike a friend, know that their siblings are still bound to return. This fighting and bickering is reported to peak in early adolescence when siblings are trying to define themselves in the eyes of the world and also as being separate from their sibling. They are also getting big enough and smart enough to do some serious psychological and physical damage to each other!
However, within reason, this healthy rivalry can also help you define who you are, make you assertive and equip you for the rough and tumble of the real world. You only have to watch any wildlife documentary to see skills being rehearsed and learnt for later adult life when the fighting won't be play-fighting but will be for real and their life may depend upon having acquired the skills they practiced with their siblings.
The oldest child
For oldest children their special status as the first born and the early period of exclusive access to both parents is thought to account for why they frequently become more successful in later and adult life than their younger siblings. They may also have gained some leadership skills and feel some natural authority as a result of the responsibilities foisted upon the oldest and of having organised younger siblings.
Upon arrival of younger siblings, the older child will consciously or unconsciously start to devise ways of getting the parents to "stop loving" the younger one(s). They will invariably irritate and/or torment their younger siblings and when the parents become aware of this, they will reprimand and may punish the older child.
The younger child
From the perception of the younger child, they arrive into a situation where all at first seems to be OK, but their older sibling(s) may needle them and get duly reprimanded.
Even just a gap of a year in age can make a tremendous difference in size, strength, dexterity, and mental capacity in childhood. The younger child, pitted against their older sibling is almost guaranteed to lose in every situation and this can build up an enormous amount of frustration.
As a strategy, the younger child will seek to find unique ways in which they can win their parents' attention and approval and will develop abilities not shared with the older sibling.
The youngest child, whilst often being indulged can also be somewhat overlooked. You only need to examine the family album to realise that every life stage of the first born has probably been exhaustively documented. The second child slightly less so and subsequent children might be lucky to have photos of key events.
In many families, it is the youngest child who generally has the greatest psychological problems in adult life.
It is a sad fact that the principal source of all the harm that one human being can do to another is the abuse of power or authority and this may be learnt tragically early by older siblings or come about as a result of the deep frustrations that build up as a result of being a younger child.
Sibling rivalry in adulthood
As adults, different choices of career, different approaches to life, choices of life partners and methods of child rearing, different religious or political views, geographical moves and whether one is perceived to be - or is - more successful than their siblings can all further inform the sibling relationship.
The rivalries of childhood can continue into adulthood and relationships can change dramatically as parents age and die, and one or more siblings may be - or may appear to be - favoured in the parent's will.
Evidently, siblings report closer ties with advancing years as perspective is perhaps gained, mortality starts to looms large and hatchets are buried.
Sibling rivalry in dysfunctional families
In dysfunctional families, the various members all distort to fit around a dysfunctional family member. This may be a parent and may be due to such factors as addiction, alcoholism, mental health issues or abusive behaviour and the other parent is frequently absorbed with trying to manage the situation as best they are able whilst, in fact, becoming co-dependent and ensuring that the dysfunction continues. Such families frequently collude to deny that anything unhealthy is going on, so even recognising and labelling the problem can be an issue.
It is well recognised that in these families, each sibling will adopt one or more of six specific roles in order to define themselves in relation to their brothers and sisters. These roles include: the 'good' parent; the one who gets blamed or scapegoated; the one that takes care of the family's emotional needs; the 'quiet' one who may be ignored or actually hidden; the 'attention seeker' or 'clown' who diverts attention from the dysfunction and the opportunist who can manipulate the situation to their own ends.
Siblings in a dysfunctional family have often been given the same life script such as “Life is hard,” or “We are the only ones that understand”, or they may have agreed to share a common enemy. Some siblings may also assume responsibility for other siblings in a way that prevents them from finding emotional independence and attaining true maturity.
When one or more siblings subsequently breaks the unspoken family pledge, they can expect the others to react with anger and such families frequently pull themselves apart in adult life.
"The surest way to make your child unhappy is to accustom him to get everything he wants".
Jean Jacques Rousseau
The indulged child
A sure-fire way to create an unhappy human being whether they be only, oldest, youngest or middle is to let the child become accustomed to getting everything that they want. This means that as the child grows so will its demands. Eventually these demands will exceed the capacity of the parents to satisfy them, and this denial will cause a shock disproportionate to the thing demanded and also because it is so unexpected by the child.
From this seething cauldron of frustration stems hate and loathing so that both having all of your needs met or too few can both be harmful to the emotional development of a healthy child. Fortunately - or as it may seem at the time - unfortunately most end up in the rough and tumble of the middle ground somewhere between benign neglect and being treated like a little prince or princess.
All children are, by definition, ego-centric and self-centred and whilst an indulged child may grow up to be very intelligent and creative, they will tend to remain self-absorbed and can become manipulative and abusive, simply because they have never matured sufficiently to develop empathy with others.
'Blended' and step families
Now, with 'blended' and step families the issue of preference comes even more sharply into focus. The unconscious biological imperative to help preserve your familial genetic line is presumably somewhat diluted by the arrival of half-siblings with who you have less of an investment and does not apply at all to step-brothers and -sisters.
Combine this with the fact that such families have frequently been formed when the children were older (or even adults) and it can be quite a big ask to expect all to get on for the sake of the two parents. When Prince William's opinion of his father's impending nuptials to Camilla Parker-Bowles was solicited, he replied - quite rightly - that it was none of his business.
Sibling relationships: A reflection
Whilst our brothers and sisters may not know us best, sibling relationships are one of the most enduring of our lives. These relationships may assume greater or lesser importance to us as we navigate the shifting sands of time and the vicissitudes of fate.
The arrival of a sibling - no matter how we view the event as an adult - can be one of the most shocking, disempowering, rage-making, jealousy-inducing events of your entire life and it can leave its mark permanently and indelibly upon the psyche. These powerful feelings are primal and it seems that many of the problems with sibling relationships cannot be adequately identified and many are in complete denial about the impact of the arrival of younger sibling which may have occurred pre-memory and possibly pre-verbally.
Furthermore, it is nobody's fault and is a story familiar to every human family on the planet and throughout the ages.
Books addressing the topic of family relationships include Family Secrets and Love's Hidden Symmetry and others listed under Emotional and Spiritual Health in Recommended Reading