GCXZ

Half and unrelated siblings, such as step, fostered or adopted siblings, used less violence with less severity, it was revealed.

In families made up of both blood-related and unrelated siblings, those surveyed used more violence towards their related – full and half - brothers and sisters, even using weapons such as heavy objects and knives, the study by Dr Roxanne Khan, Dr Vanlal Thanzami and Jennifer Bowling from University of Central Lancashire concluded.

"This study focused on the 'Cinderella Effect' that, according to evolutionary theories, suggests that stepchildren are more likely to experience neglect or abuse than those related by blood. We wanted to explore whether this was the case between full, half and unrelated siblings," Dr Khan said.

"Contrary to what we expected, this study did not support the 'Cinderella Effect' occurring within siblinghood.

"Sibling relationships are very complex so we expect a number of other factors may have influenced our results.

"It could be the case that full siblings expect less retaliation for using violence against their blood brothers and sisters, compared to the uncertain revenge of half or unrelated siblings, and this could explain the friction."

The team asked to 315 brothers and sisters, aged 16 to 55, how they fought with their siblings and about the severity of the violence.

Participants provided information about 456 full siblings, 123 half siblings and 39 unrelated siblings.

The findings will be presented at the British Psychological Society Division of the Forensic Psychology annual conference in Glasgow on Friday, June 27.