An LSE research used in a Panorama programme about the sexualisation of young children, has indicated that a quarter of children looked at pornography in 2010.
It showed that one in eight of young people aged between nine and 16 received messages of a sexual nature while surfing online or through their mobile phones.
In addition, more than half - 52 per cent - go online when they are in their bedrooms on in a room alone, making it hard for parents to monitor what they are doing.
According to the research, 24 per cent of nine to 16-year-olds have seen some form of pornography in the last year - through the Internet, television, magazines or DVDs.
Of those, 41 per cent of parents believed that their children had not seen any such images.
Livingstone said there was cause for concern about the amount of time children spent online and what they do while on the Internet.
"I think there's a lot of experimentation going on," the Telegraph quoted Livingstone as saying.
"I think a lot of that is about sharing experiences, being in touch, seeing if other people are living the life that you are.
"Within that there is clearly a lot of flirtation and some degree of sexual experimentation," added Livingstone.