People can only handle so many choices before decision-making skills fall apart.
Humans and other animals can only handle so much variety before confusion and indecision set in.
Speed dating usually presents us with an unnatural number of choices, so people often choose the wrong mater or can't choose at all.
The findings help to explain problems with other situations involving variety, such as long menus.
Speed dating presents individuals with such an unnatural number of choices that people either usually avoid making selections or choose the wrong person, according to a study in the latest Royal Society Biology Letters.
The findings indicate people, and also non-human animals can only handle so much variety before decision-making skills fall apart. The phenomenon helps to explain why lengthy restaurant menus, long retail offerings, and other situations muddle our minds.
"Our ancestors lived in relatively small, tight-knit communities, so they likely never encountered the level of variety that humans today confront," co-author Alison Lenton told Discovery News. "Thus it seems likely that our minds simply adapted to deal with the level of variety with which we were regularly confronted."
Lenton, a lecturer in the Department of Psychology at the University of Edinburgh, and colleague Marco Francesconi analyzed decisions made by 1,868 female and 1,870 male participants in 84 commercially run speed-dating events. When these single individuals registered for the events, they reported their age, weight, height, educational attainment, religion, occupation and smoking habits.
At each event, participants met members of the opposite sex in "mini-dates" lasting 3 minutes. Within 48 hours, participants communicated their decisions.
Although men made significantly more proposals than women did, overall, as option variety increased, the number of proposals decreased. Some participants made no choices at all, while those who did choose were less likely to select the consensually preferred mate option.
Many left the speed dating events just as they had entered them: single.
"We think it has to do with the way that humans tend to go about making judgments, that is, we have a tendency to make relative judgments rather than absolute judgments," explained Lenton. "We compare options to one another rather than to some abstract ideal, so the more dates one goes on, the more one perceives/detects variety among the options."
Prior research indicates non-human animals also make poor choices, or none at all, when confronted with too much variety. For people, the discovery could help to explain all sorts of transaction and social failures, from inability to select a proper home after viewing dozens to what could be called the "George Clooney effect" -- the inability of some people to fully settle down even when dating multiple attractive, wealthy and otherwise desirable partners.
"Overall, too much variety may mean, as suggested by our findings, that people put off making a decision," Lenton said. "Perhaps this is one reason why people today get married at a later age, especially in large cities where presumably there is a wider variety of options -- that is, greater diversity among people."
"They show that variety backfires and is an impediment to choice in the context of mate choice, something that has been shown in consumer choice, and have myself documented in the context of supermarket assortments," commented Barbara Fasolo, a researcher and lecturer in the Department of Management at the London School of Economics and Political Science.
"Advice for the speed daters is to bring a checklist and articulate one's preferences just before entering the session, and avoid comparing mates among themselves but rather, in a more absolute sense, evaluate the match of a person against one's preferences," she advised.
"And with these in mind," Fasolo concluded, "try to prioritize questions to be asked and try to allocate attention accordingly. But, as choice is mutual, it is also important to do this in a way that doesn't make one think too much in the session, as looking too conscientious might detract to one's appeal."