Scientists have made a surprising discovery: The more options you have for choosing a lover, the likelier you are to end up with no-one.
British investigators, in a new study released on Wednesday, looked at the strange dynamics of choice in speed-dating, a fashionable way for singles to meet.
Speed-daters race through a rota of one-on-one meetings, judging each person for suitability after a conversation of a few minutes that ends when a bell sounds.
Assessing large numbers of candidates was not a problem in itself, the researchers found.
In fact, many speed-daters found more potential partners when they were able to cast their net into a larger pool.
But this advantage only worked when the available candidates were all broadly similar.
When candidates were too dissimilar, speed-daters became confused by many conflicting factors -- and often failed to choose anyone.
"There are models of human 'rationality' which posit that variety is a good thing," said researcher Alison Lenton at the University of Edinburgh in Scotland.
"What will be surprising to some people is that our results suggest that increasing option variety leads to chooser confusion. People are more likely to choose no-one at all when faced with greater variety."
The study, published in the British journal Biology Letters, tracked 1,868 female and 1,870 male participants at 84 commercial speed-dating events.
Hopeful singles gave details of their occupation, education level, age, height, weight and religious affiliation, allowing researchers to gauge differences.
The women's mean age was 34.3 years and men were aged 35.6. Twenty percent of women and 27 percent of men were in professional or managerial positions, and the remainder classified themselves as "skilled non-manual" or other occupations.
Speed-daters met in groups and engaged in three-minute encounters with between 15 and 31 singles of the opposite sex.
After the event, the organizer matched up individuals who indicated a mutual interest in each other, thus opening the way to a possible date.
Big speed-dating events typically generated 123 such "proposals," or shows of interest, when candidates were similar, the researchers found. But the number dropped by more than a quarter, to 88, when candidates were varied.
Small speed-dating events would lead to 85 proposals when candidates were similar. But this fell by nearly a third, to 57 proposals, when candidates were varied.
Men were generally keener than women in formulating a proposal -- but were also likelier to be stumped by choice.
In short, variety is fine... but in manageable doses.
"Dealing with variety requires attention and memory, and we have only so much capacity for each," Lenton explained in an email with AFP.
Extending encounters by 10 minutes might not greatly change results, she said.
"It is extremely common for us to make quick judgments about other people, even in a matter of seconds. And once those judgments are formed, they can be difficult to change."
Amber Soletti, who runs a speed-dating company in New York, said grouping singles by interest or physical preferences boosted chances of a successful connection.
Her company, OnSpeedDating.com, offers 75 niche groups, such as "Asian Persuasion," "Fitness Singles" and "Worldly Singles" who like to travel.
Soletti started the company after failing to find anyone of interest at general speed-dating events.
"I only like to date men 6-foot-1 (1.85 metres) and taller. I always went to single events that had shorter men, so I didn't find anyone," she said by phone.
But now, "If I go to our tall event, I have a better chance of meeting someone," she said.
"People know what they like."