Evolutionary psychologist Robin Dunbar (of the Dunbar's Number fame) and colleagues analyzed 2 billion anonymized telephone calls and 500,000 text messages to arrive at this scientific conclusion: romance is driven by women.
But before you say "Duh!" the study also showed something much more interesting:
... women start to switch the preference of their best friend from about the mid-30s, and by the age of 45 a woman of a generation younger becomes the "new best friend", according to Professor Dunbar.
"What seems to happen is that women push the 'old man' out to become their second best friend, and he gets called much less often and all her attention is focussed on her daughters just at the point at which you are likely to see grandchildren arriving," he says.
Prof Dunbar also claims that the findings suggest that human societies are moving away from a patriarchy back to a matriarchy.