It's a tricky issue. There's lots of studies showing that people form pretty meaningful impressions quickly, as you're saying, and I think speed dating captures some of that.

On the other hand, there's lots of evidence suggesting that the things they were measuring are important for things like long-term relationship survival, etc. There's also studies showing that these "thin slices", while accurate, are not as accurate as what you'd get from intimate long-term knowledge of someone.

This isn't anything astonishing, but I have difficulty interpreting this as much more than "things like personality and attitudes are not very predictive of your superficial attractions to potential partners." I don't mean "superficial" dismissively, I just mean it in the sense of "not based on very much information."

Another way of looking at it is: how could you predict attraction in that time frame based on longer-term, deeper-seated attributes, when that kind of timeframe doesn't allow for assessment of those sorts of things? It's one prediction, but I doubt if you stepped back and came at it without knowledge of this study, that you'd make that prediction. I certainly wouldn't (I'm trying to imagine me predicting my relationships from the first 4 minutes--sure, I'd be able to guess pretty well who I definitely wasn't attracted to, and maybe who I was definitely was attracted to, but beyond that? pbfbfbtttt...)

I wasn't able to predict my most meaningful relationships from a month or so of being around them, sometimes on daily bases. Looking back at them, I might have had some kind of subconscious reaction I wasn't able to process, but I wasn't aware of what it meant at the time, which renders it useless.

What looks amazing from the outside might be quite stressful from the inside, and vice-versa. I think we aren't able to predict a relationship before we experience it because each person adapts to the other, and the result is undetermined before the process starts. A person becomes changed in a relation, we can't predict even how we are going to be, let alone the significant other. That has been my experience - I'm rather pessimistic at dating services being able to match people up. It's more of a game of chance.

Astute observations.

However, do dating services ever do consistently better than chance (whatever chance means in such situations)? Plenty of Fish IIRC used to publish lots of stats.

This is problematic for the same reason technical interviews are: some people are just naturally better at them.

"... could barely muster a few words throughout the conversation" could easily be "shy and embarrassed", though. In a less weird setting than speed dating, they might have more to say.

Of course, a first date is also a pretty weird setting. The advantage is, it lasts long enough that there's a chance the "shy and embarrassed" can wear off, and the more normal person can come through.

Is someone shy and embarrassed in that context also likely to be similar when making new friends, negotiating in a business context, etc? The people I know who have been reserved at first, have generally been more reserved in all situations.

That might be more attractive to other shy people, I'd guess.

I'm immensely shy but relatively good at pretending I'm not. I can't imagine finding that characteristic attractive? I suppose some people want a wallflower?

Do other shy people look for a partner who is shy?