So what is it that causes the poltergeist phenomenon? Aside from accusations of hoax and exaggeration, which although applicable to a number of cases by no means apply to them all, the most popular theory is that the poltergeist is caused unwittingly by a human agent, usually a teenage girl. Researchers believe that a troubled adolescent unconsciously manipulates objects using psychokinesis (PK), a type of energy generated in the brain. According to researchers at the Rhine Research Center Institute for Parapsychology at Duke University, Durham, North Carolina, poltergeist activity is the physical expression of psychological trauma. However, more natural explanations are often the cause of what appears to be a poltergeist disturbance. Electromagnetic Interference (EMI) has been found to be behind at least one supposed poltergeist investigated by Midlands (UK) investigation group Paraseach, and there is an increasing amount of evidence to show that it could explain many more cases.

Perhaps this might help to cast light on poltergeist cases such as those of Eleonore Zugun and Carole Compton. However, this does not explain how enough power is generated to move objects such as heavy pieces of furniture, or to shower a room with stones, make objects appear from nowhere, or start fires, if accounts of such phenomena can be trusted.

There are also a number of poltergeist cases where the people involved have no psychological problems at all, and where there are no adolescents in the household. How can we explain these? A further point is that there are millions of troubled teenagers all over the world, but the vast majority do not cause poltergeist activity to occur. Other researchers have suggested that 'spirit entities' are responsible for the phenomena, perhaps generating the power by attaching themselves to suitably disturbed teenagers. But the very nature of these hypothetical 'spirits' means that scientifically at least, they cannot be properly investigated, though there are interesting tape recordings of a 'voice' from the Enfield Poltergeist case. However, if accounts of the more extreme unexplained occurrences alleged to be caused by poltergeist activity are themselves exaggerated, or even completely unreliable, which is entirely possible in older cases, then no further explanation is required.

Nevertheless, the inability to find a convincing explanation for the phenomenon, the significant amount of poltergeist cases exhibiting similar characteristics occurring over a long period of time in widely different cultures, and the bizarre but somehow consistent nature of the phenomena, make the poltergeist perhaps the most baffling and enduring of unexplained mysteries.

Born on 24 May 1913, Eleanore Zugun was a Rumanian peasant girl who lived in the village of Talpa, in the north of the country. In February 1923, when she was eleven years old, she went to visit her grandmother's house at Buhai, a few miles away from her village. On the way she found some money by the side of the road, and when she arrived at Buhai she spent it on sweets and ate them all. Her 105-year-old grandmother, who had the reputation of being a witch, overheard Eleonore and her cousin arguing about the sweets, and warned her that the devil (Dracu in Rumanian) had left the money to tempt her, and from then on she would never be free of him. The next day poltergeist activity began.

Stones crashed against the house and broke windows, and small objects near to Eleonore jumped up and flew about. Her superstitious grandmother was convinced that the girl was possessed by the Devil and Eleonore was quickly sent home to Tulpa. But here, three days later, the poltergeist started again. A jug full of water rose slowly into the air and floated several feet without any water being spilled. A trunk shook violently up and down, a porridge bowl flew at a visitor and hit him on the back of the head causing a painful wound.

The phenomena continued and Eleonore found refuge in the monastery of Gorovei. But after three weeks there, with the violence of the phenomena unabated, she was locked in a lunatic asylum. Fortunately, newspaper accounts of her strange story reached eminent Austrian psychical researcher Fritz Grunweld in Charlottenburg, Germany, who, with the help of Kubi Klein, a journalist form Czernowitz, managed to get her sent back to the monastery where she could be properly observed.

Grunewald took detailed shorthand notes of the amazing phenomena which took place between the 9 and 18 of May, 1925. (These were edited and published after his death by Professor Christoph Schröder in the Zeitschrift für psychische Forschung, vol. I, 1927.) The most common type of phenomenon were object -movements, ranging from the slow movement of a large pot on the oven, to the sometimes violent throwing of things at or close to people. Objects also appeared seemingly from nowhere (apports), and there were occasional knocks, and, once or twice, matches were mysteriously set alight. The poltergeist also began slapping the girl.

In July 1925, however, Grunewald died of a heart attack aged forty-one, and the unlucky Eleonore was once again left in the care of her apparently unconcerned family. Fortunately, later that year, she found another protector. This was in the form of an attractive young Viennese woman - the Countess Zoë Wassiliko-Serecki, part Rumanian, who had been connected with psychical research for years, and also had an interest in psychoanalysis. When she visited Eleonore at the monastery of Gorovei in September 1925, she found an uncared for, dirty and very frightened girl.

While there, the Countess saw for her self the bizarre phenomena. She wrote a short book about Eleonore's case, later published as Der Spuk von Talpo (Munich, 1926), and by January 1926 had managed, after complicated negotiations, to bring Eleanore to Vienna to live with her in her flat.

Here, Eleonore was happy and healthy and before long the Countess had her training as a hair-dresser. Though Eleonore was emotionally stable at this time and not in the psychological condition usually associated with poltergeist activity, the phenomena continued as before. The Countess kept a diary of events and divided the phenomena produced by the girl into a number of main categories. The movement of objects and apports of a range of items from various rooms in the flat were common, and object-movements even took place outside in the afternoon sun.

In 1724, a 'naked, brownish, black-haired creature' was caught in the woods near the German town of Hamelin. The 'creature' was found to be a feral boy of about twelve, who at first behaved like a wild animal eating birds and vegetables raw, before becoming more docile. Given the name Peter the boy was made the possession of King George I of England where he was later taken. In England he spent most of his time either lying by the fire or roaming through the countryside. Peter never learned to talk and lived the rest of his life in England until his death in 1785. It was later discovered that Peter had only been living wild for about a year before his discovery and had actually left home because of physical abuse by his father. It has been suggested that autism may explain his behaviour.

A boy of about 12 years of age, who later became known as Victor, was found foraging for food in the woods near Aveyron, southwestern France in 1799. It was soon obvious that Victor's was a boy only in appearance, he ate raw and rotten food, sat rocking back and forth for hours, and could not distinguish between hot and cold. Despite intensive study by noted French Physician Jean-Marc Gaspard Itard, Victor only ever learned two words, lait (milk) and Oh Dieu (oh God), and died in 1828 at the age of 40.

The case of Victor demonstrates that feral children have long been of particular interest to the scientific, medical and educational community. Study of such children can cast light on the differences and similarities between human and animal natures, the process of how language is acquired, and whether certain human characteristics are learned or genetic. Unfortunately we know practically nothing of any feral child's life in the wild before their capture. There are also no cases on record of a successful attempt to integrate a feral child back into society if he or she has lived in the wild from a very young age. Due to this lack of ability to adapt to civilisation most feral children die at a relatively young age.