David and Louise Turpin stand accused of holding their 13 children in shackles at their California home.
The allegations of torture seem impossible to comprehend next to the family photos circulated in the press that show the smiling group on days out at places like Disneyland.
Prof Browne, director of the Centre for Forensic and Family Psychology at the University of Nottingham, says it is more common to see cases where there is one child and the parent or parents cannot cope, so the situation spirals out of control.
