After a few pages of standard questions on education, income and physical appearance, comes the deep stuff

Gonzaga has been with the company since 2005 and is genuinely passionate when he talks about relationship science, but I remain sceptical that a computer algorithm can fathom the heart

How well do I stick to a plan? Am I easily discouraged? How often do I do nice things for other people? There are 250 questions in all, and it takes an extended lunch hour to complete. (Maybe others could do it quicker – by the end I was flagging and finding it hard to decide whether I was “very”, “somewhat” or “not at all” romantic. Final answer: “somewhat”. ) The computer runs its judgment over me. There’s a moment of suspense before the screen delivers its verdict: eHarmony has “no appropriate matches” for me at the moment. I haven’t felt so crushed since the humiliation of the end-of-school disco.

After a week, I’ve still not had a single match, so I decide to look at the results of my psychometric report. Under the “Agreeableness” heading, the report tells me: “You are best described as: CONSISTENTLY TAKING CARE OF YOURSELF”. Those are their capitals, by the way, not mine. Delving a little deeper, I find myself described as “reserved, private, introverted”, qualities I have never been accused of having by anyone who’s met me. I think I’ve discovered why I don’t have a date: eHarmony thinks I’m a sociopath.

Pasadena is a pleasantly quiet, residential suburb of Los Angeles and a surprising location for one of America’s brightest dotcoms. EHarmony was born here, the unexpected child of Dr Neil Clarke Warren’s marriage-counselling practice. In his work, Warren saw too many fighting couples who, he realised, were fundamentally mismatched in the first place. He decided to dedicate his own scientific research to finding out what kept couples together in the long-term; his findings provided the basis for eHarmony’s original model and a multi-million dollar company.

In the basement of the eHarmony offices, Dr Gian Gonzaga, the company’s head of research and development, sits in the command centre of lumen review their “relationship laboratories”. EHarmony has seven PhDs on its staff, and its R&D team is constantly revising and extending Warren’s original thesis.

“Compatibility is something that people don’t see,” says Gonzaga, a handsome statistician in his 30s who, it disappoints me to learn, has been married two years himself. “You don’t know where the conflicts are likely to come when you first start in a relationship, because a lot of people haven’t been there. I haven’t been married for 30 years, for instance – so I don’t know what’s going to be important 30 years from now.”

Surrounded by recording equipment and monitor screens, Gonzaga can listen in on the interactions that are taking place in the next-door rooms, where couples are talking about their lives: love, lunch, laundry

He picks up a napkin and starts drawing a flowchart on the back of it, combining phrases like “dyadic adjustment scale” and “regression analysis”, with helpful little diagrams of stick people. “If we match you with someone,” he explains, “its because you share the same characteristics in the same ways that the happiest married couples we’ve interviewed share. The more something impacts relationship satisfaction – having the same faith, say, or being a similar personality type – the heavier they’re weighted in the algorithm. It’s like walking into a party and instead of having to talk to all 100 people, here are the 10 you should start with, the ones you have the best chance to get along with in the long haul.”