Dr Thomas Dixon, the presenter of this new multi-part enquiry into the meaning and experience of friendship over the last half-millennium (from 24 March) turns out to hold the somewhat eye-catching title of director of the Centre for the History of the Emotions at Queen Mary, University of London. Keen on personal testimony as well as academic analysis, he began his investigation not only by separating his subject into its three traditional forms – kinship, utility and affection – but in trying to work out how many friends he himself possessed.A Facebook count-up realised 112 names, which Dixon seemed to think was on the small side in a cyber-world where 3,000 isn’t uncommon. He was supported in this assumption by the University of Oxford’s Professor Robin Dunbar,