Young people’s brains are failing to develop properly after being overexposed to the cyber world at an early age, it was claimed.
Baroness Greenfield, professor of pharmacology at Oxford University, said a decline in physical human contact meant children struggled to formulate basic social skills and emotional reactions.
She criticised the “unhealthy” addiction to Twitter among some users who resort to increasingly nasty outbursts under the “sanitised and often anonymous guise of the web”.
In an interview with The Daily Telegraph, she also raised concerns over the “narcissistic” nature of sites such as Klout, which measures users’ popularity and influence on social networks.
The comments come just 24 hours after teachers warned that over-exposure to technology was damaging children’s ability to concentrate in the classroom.
A survey of secondary English teachers revealed that more than three-quarters thought pupils’ attention spans were shorter than ever before.
Baroness Greenfield quoted figures showing that more than half of 13- to 17-year-olds now spend more than 30 hours a week using video games, computers, e-readers, mobile phones and other screen-based technology.
She said the human brain evolved to its surroundings and needed a “stimulating environment” to grow and properly develop.
But she warned that a reliance on social networking and increased use of computer games could effectively “rewire” the brain.
The academic is due to present her findings in a speech to the Early Childhood Action group, which has been established to campaign for reforms to early years education.
Speaking ahead of the organisation’s inaugural conference at Winchester University next Saturday, she said: “Most of us, by the time we reach adulthood, have an inner conceptual framework that enables us to interpret the world and have a robust sense of our own identity.
“My fear is that having an identity which is externally constructed and dependent on the moment-by-moment reactions of others will make people less robust and constantly at the mercy of the outside world.”
She added: “What concerns me is when screen-based technology is used a lot, or by young people who don’t have the counterbalance of a highly-developed brain.
“You are only good at what you’ve rehearsed, and if you haven’t rehearsed looking someone in the eye, interpreting body language and using appropriate physical contact, then you are not going to be good at those things.”
Baroness Greenfield said that social networking websites such as Facebook and Twitter created a generation with a child-like desire for constant feedback on their lives.
Repeated exposure leaves some users with an “identity crisis” as they crave constant attention from followers, she added.
She highlighted the example of Klout, which provides users with a score based around their influence on social networking sites.
“To have this ultimate beauty contest showing how much better you are than everyone else can only lead to sadness because there will always be someone who scores higher than you,” she said. “It means you are constantly lacking in self-esteem, over narcissistic and, at the same time, in constant anxiety.”
Baroness Greenfield also warned that social networking websites were fuelling bullying, adding: “The anonymity of the web can make it easier to do and also removes the constraints that would normally apply for what one might regard as human nature.”
Read more: Telegraph