Sisters, Sisters, Never Were There Such (Devoted) Sisters

I was sorry to learn that Joan Collins no longer gets on with her sister, Jackie. The sad news was publicly revealed on the South Bank Show just last night, and it's only Friday evening as I write, but of course we media folk get to hear these things in advance. The word trickles down.

I can't tell you how devastated we all are in this office. The much-married actress Joan (66) and the blockbuster-writing Jackie (57) are two great staples of the broad-based modern entertainment industry which now encompasses the media, the pop world, computer science, cosmetic surgery, educational theory, Fendi handbags and artistic endeavour of every kind, so our empathy at The Irish Times will come as no surprise.

"You can choose your friends, but you can't choose your family", Joan told a sympathetic Melvin Bragg (in fact, the sympathetic M. Bragg). "We drifted apart. I love my sister, but I'm not as close to her as I used to be."

Drifted apart, is it? Talk of Mae West - "I used to be Snow White, but I drifted." Joan has more British reticence than you might think (take it from me) so you can read between the lines and instantly know that the siblings are at daggers drawn.

It is all very sad, but those of us who are intimate with Joan and Jackie saw it all coming a long way off. As for friends v family, anyone who knows anything about modern genetic engineering knows that choosing your family has become a lot easier these days, and as the links in the chromosome chain continue to be mapped, it will be simpler still very soon. Moreover (hate that word) you don't choose friends - (the cruel truth is that) they choose you. Joan has a problem there.

But the principal problem Joan has relates to her own forays into fiction, which did not please Jackie (one little bit). Quite a few years back, Jackie was perfectly happy to see Joanie star in Jackie's The Stud, but we now learn she was very displeased when Joan began writing romances like Prime Time.

Nor did Jackie lend much support when Joan became embroiled in a row with Random House about delivering a "fragmented" manuscript, a row which Joan eventually won. Jackie was notable by her absence at the subsequent celebrations.

The news of the row has already sparked off a hugely interesting debate on (the subject of) sibling rivalry. Prof Virginia Molgaard, a psychologist at Iowa State University who specialises in sibling rivalry (the field of) has been quoted as saying: "We often find that children select different activities to excel in, in order to avoid comparisons. But when two children try to be good at the same thing, there are apt to be comparative evaluations. That often leads to one-upmanship, or putting people down."

Don't be talking, man. Anyone with brothers or sisters will understand. As for the tennis-star sisters Venus and Serena Williams, well, they are obviously the exceptions who prove the rule.

Anyway, I spoke to another senior academic, Prof Winnie Gruyling-Kafshtun of the Open Eight 'Till Late University, who turns out to be a sister of Prof Molgaard, and doesn't agree with Virginia at all.

She points out that while Virgina got a first in her primary degree, and she herself secured only 2.1, she nevertheless managed to secure her PhD a year before Virginia. And though both of them are eminent in the field of sibling rivalry, she currently has more papers published than Virginia, even if the latter now has a BBC contract to present a prime-time series while Winnie is still only an occasional guest on Radio 4.

I drew the professor's attention back to the fact that what was under discussion was the breakdown in the relationship between Joan and Jackie Collins, and asked her about what is known in the psychological literature as the "Kylie and Danii approach." According to the Guardian, this is characterised by a desperate and unconvincing attempt to seem like the best of friends in public when the underlying rivalry is embarrassingly clear to all.

The professor then told me in no uncertain terms that this was all nonsense, and that rumours of a rift between her and Virginia were entirely false. "Comparing our relationship in the academic field to a sibling relationship in the world of popular music is an entirely reductive exercise. And I'm sure that my darling sister won't take it amiss if I point out that I always had a better rapport with my fans than she ever did with hers."