Reflecting back on social interactions to which I've recently been party, if you'll forgive the pun, I've noticed another divide which manifests on these occasions. Mostly, in academic departments, the staff on conditions other than academic are under-represented - often entirely absent. On occasion they are present, but in a service / organising capacity. Sometimes - if there are sufficient of them - they attend, but keep to themselves, apart from their "academic" colleagues. Seldom are they there, in a purely social capacity, mingling with their colleagues on academic conditions, as equals.
Very often these "non-academic" staff are black. Very often their "academic" colleagues are white. But not always. And, in my experience, the black "academics" are more likely to attend than the "non-academics" of any shade - beyond those who are required to be present in an organisational capacity. The class distinctions persist even beyond the "racial" ones, it seems.
Part of the reason for this perhaps lies in what happens at many of these things. They may be termed "social", and there may be eating and drinking and music - but often the discussion sounds awfully similar to that which one would hear on an average day in the tea room, the passage, the staff meeting. Work. An interesting discussion with an Honours student where terms like "intertextuality" and "genre" are more likely to feature than "babelas" or "bokkie", or some grumbles about space allocation, or non-recurrent budget impacting on teaching load. And, of course, mutters about rising administrative load and decreasing administrative support. (Discussions on cricket don't count. Cricket is by all observable accounts a routine part of the average academic's day.)
So what do "non-academic" staff discuss when they get together? Rising administrative load, decreasing (central) administrative support - generally framed as "Bremner / Faculty shoving more stuff at us without the resources to do it" - and... patronising, hostile or arrogant attitudes of academics. Patronising, hostile or arrogant attitudes of students. Things that sound, to an uninformed ear, awfully like... work. (Not much cricket. But then cricket isn't really a routine part of the average "non-academic's" day.)
If social mixing across the divide is to succeed, perhaps the first step would be some kind of consciousness-raising process to enable staff to discover that there is some kind of life beyond work... and that it's OK to admit to having one, really.