More than 750million people across the world use Facebook to share photographs and videos and post regular updates of their movements and thoughts. Millions have also signed up to Twitter, the 'micro-blogging' service that lets members circulate short text and picture messages about themselves.
Baroness Greenfield, former director of research body the Royal Institution, said: 'What concerns me is the banality of so much that goes out on Twitter.
The academic suggested that some Facebook users feel the need to become 'mini celebrities' who are watched and admired by others on a daily basis. They do things that are 'Facebook worthy' because the only way they can define themselves is by 'people knowing about them'.