Serious health problems including cancer, strokes, heart disease and dementia are being made worse by lack of personal interaction and increased use of social networking sites such as Facebook, it has been suggested.
Dr Aric Sigman warns in the latest issue of Biologist, the journal of the Institute of Biology, that society is being badly affected by the increasing lack of face-to-face contact.
He says that interacting in person has effects on the body that are "probably an evolutionary mechanism that recognises the benefits of us being together geographically".
He cites evidence that levels of hormones such as the "cuddle chemical" oxytocin, which promotes bonding, change depending on whether people are in close contact or not.
He is particularly concerned about the "huge changes" in the way children interact. "A quarter of British children have a laptop or computer in their room by the age of five, and they have their own social networking sites, like the BBC's myCBBC."
These, he says, may lead to isolated lifestyles that change the way genes work, upset immune responses, hormone levels and the function of arteries, and influence mental performance.
"As an Internet Psychologist I can partly see where Dr Sigman is coming from. However, he is making jumps in logic and his research is flawed. For instance, his data only go up to 2007, before Facebook really became popular. Also other evidence shows that Facebook users engage in MORE face-to-face meetings, not less. So, if anything, social networking improves your health." - Graham Jones, UK