Without a few unusual people, human behaviour would have remained a mystery - ordinary people whose extraordinary circumstances provided researchers with the exceptions that proved behavioural rules.
Claudia Hammond revisits the classic case studies that have advanced psychological research.
When a young woman was brutally killed in a prolonged attack in New York in 1964, not one of 38 witnesses called for help until too late.
The case led to the naming of the phenomenon known as Bystander Effect.
|01||02||The Wild Boy Of Aveyron||20080514||20081130|
In 1800, 12-year-old Victor emerged from the woods of the Aveyron District, naked and behaving like an animal.
It was estimated that he had been living wild since the age of about four.
Doctor Jean-marc-gaspard Itard devised a revolutionary programme of training for the boy, which met with partial success.
The story is repeatedly quoted in the nature-nurture controversy, but it provides no conclusive proof either way.
As with all case studies, it can be used to defend different theories.
Nevertheless, many still benefit from Victor's legacy, as children with learning difficulties and others, especially those in Montessori nurseries, are taught by the method of hands-on play devised by Itard.
|01||03||The Man With The Hole In His Head||20080521||20081207|
Phineas Gage was a railway worker in 19th-century Vermont who survived a bizarre accident.
A metre-long iron rod shot through his head, changing him and the study of neuroscience forever.
|01||04 LAST||Little Hans||20080528||20081214|
A phobia of horses developed by a small boy living in Vienna in 1904 seemed unlikely evidence for the Oedipus complex.
But for Sigmund Freud, this was the proof he had been waiting for.
His study of Little Hans was the first recorded case of child psychoanalysis, and, with its detailed recording of a how a child makes sense of the world, continues to provide rich pickings for all who are interested in child development.
Claudia investigates the legacy of the study, and visits one of the centres run by Childhood First, which deals with some of the most disturbed and damaged children using a model informed by psychoanalysis.
|02||01||H M - The Man Who Couldn't Remember||20100811|
When a 27 year old man known in the text books simply as HM underwent brain surgery for intractable epilepsy in 1953, no one could have known that the outcome would provide the key to unravelling one of the greatest mysteries of the human mind - how we form new memories.
HM was unable to remember anything that happened after the operation, which was conducted by Dr William Scoville in Hartford, Connecticut, though his life before the surgery remained vivid.
For 55 years, until he died in December 2008 at the age of 82, HM - or Henry Molaison, as he was identified on his death - was studied by nearly 100 psychologists and neuro-scientists; he provided data that enabled them to piece together the memory process.
The research was first coordinated by Dr Brenda Milner of McGill University and then by Professor Suzanne Corkin at MIT.
Both women got to know Henry well, but he never got to know them; for him each meeting with them was the first.
His inability to form new memories meant that HM was unable to look after himself, but he remained cheerful, with a positive outlook on his condition.
He was happy, he maintained, to provide information that could help others.
And this he continues to do, even after death.
His brain was dissected by Dr Jacopo Annese of the Brain Observatory at UCSD, and is the subject of an ongoing on-line collaborative study.
Producer: Marya Burgess
A man known as HM provided the key to one of the mysteries of the human brain.
|02||02||John - Joan - The Boy Who Was Raised As A Girl||20100818|
Janet and Ron Reimer's twin sons, Bruce and Brian, were born in Winnipeg in Canada in August 1965.
All went well until April 1966, when the twins were circumcised.
In the process, Bruce suffered a catastrophic injury to his penis.
A year later, on the advice of Dr John Money, founder of the Gender Identity Clinic at Johns Hopkins University Medical Centre in Baltimore, Bruce became Brenda and the Reimers began to raise their son as a daughter.
John Money published the case as one of successful gender re-assignment in 1975, when the twins were 9.
Yet by the time Brenda was a teenager she was suicidal.
When her parents finally told her the truth, Brenda decided to change back to her original gender; she became David Reimer.
The medical literature, however, continued to quote John/Joan as evidence of successful gender reassignment, until Milton Diamond, Director of the Pacific Centre for Sex and Society at the University of Hawaii, finally tracked down David Reimer and published an article in 1997.
For the first time it was revealed that the re-assignment had not been a success.
Journalist John Colapinto followed it up with a book about David in 2000.
As a man, David appeared finally to have found happiness in marriage and stepchildren.
However, a series of events took their toll: his twin brother's death, the loss of his job, and separation from his wife all proved too much and he took his own life on 4 May 2004.
Producer: Marya Burgess.
|02||03||S B - The Man Who Was Disappointed With What He Saw||20100825|
Claudia Hammond re-visits the case of Sidney Bradford, born in 1906, who lost his sight when he was 10 months old.
When it was finally restored with corneal grafts at the age of 52, a lecturer in Experimental Psychology at Cambridge, Richard Gregory, began a series of tests on SB - a study that would launch Gregory's career as a world-renowned expert in visual perception.
For this programme, in his last broadcast interview before his death in May this year, Richard Gregory, Emeritus Professor of Neuropsychology at Bristol University, accompanied Claudia Hammond to the London sites he'd visited with Sidney 50 years earlier.
At the Science Museum SB was captivated by the Maudsley screw-cutting lathe from 1800; he enjoyed the flurry of pigeons in Trafalgar Square, and laughed at the giraffes at London Zoo.
But in general SB found the visual world a disappointing place.
He died less than two years after his sight was restored.
His reaction differed greatly from that of Mike May, an American who lost his sight aged 3 and recovered it when he was 43.
What's become apparent from such cases is that humans have to 'learn' to see; without accumulating visual experience from which the brain can make sense of what the eyes see, vision is of little use.
Claudia Hammond hears from consultant ophthalmologist, William Ayliffe about the other historical cases of recovered sight, and visits Dr Steven Dakin in the Department of Visual Neuroscience at UCL
Producer: Marya Burgess.
The story of SB, who had his sight restored after over 50 years of blindness.
|02||04 LAST||Dora - The Girl Who Walked Out On Freud||20100901|
Dora was the pseudonym Sigmund Freud gave to the teenage girl who claimed that her father had offered her to his friend in exchange for the continued sexual favours of the friend's wife.
Freud used this, his first case history, to show how the interpretation of dreams could be used in analysis.
Also to illustrate his new theory of infant sexuality, and to explain transference.
Although Freud said he believed Dora's account of the adults' love triangle, Dora ended the analysis after just 11 weeks.
Freud wrote up his account immediately, but didn't publish it until 1905, as Fragment of an Analysis of a Case of Hysteria.
In the 1970s the case was taken up by feminists to discredit Freud's theories.
Claire Pajaczkowska made a film about it: Dora: A Case of Mistaken Identity.
American psychoanalyst, Karin Ahbel-Rappe, asserts that Dora, a vulnerable teenager, was badly let down by Freud.
So does Anthony Stadlen, a psychotherapist who has researched the real people behind the pseudonyms in Freud's case histories.
Dora was in fact Ida Bauer, later Ida Adler, and the image of the self-obsessed hysteric perpetuated by Freud and his followers was apparently untrue.
Janet Sayers, Professor of Psychoanalytic Psychology at the University of Kent, and Michael Billig, Professor of Social Science at Loughborough University, also feature in the programme.