People can recognise, from just ten seconds of video footage, whether one person has the hots for another.
Skyler Place and colleagues made their finding using footage of couples on speed-dates. Fifty-four students observed dozens of 10-, 20- or 30-second clips of real speed dating interactions and attempted to say in each case whether each person was romantically interested in the other.
The researchers had access to the daters' real decisions about whether they were interested in any of their speed dates, and were able to compare these with the students' judgements.
The students performed more accurately than would be expected had they simply been guessing. They judged the interest of the male daters with 61 per cent accuracy and the female daters with 58 per cent accuracy. Their accuracy was unaffected by the length of each clip, but was higher when the clip was taken from the middle or the end of a dating interaction. Students currently in a romantic relationship outperformed those who weren't.
The fact the students were less accurate when judging the romantic interest of females compared with males was just as the researchers had predicted. Place's team said it made sense for women to "behave more covertly and ambiguously" because there is more at stake for them in making a potential mating choice. By hiding their romantic interest, the researchers argued, women are able to give themselves more time to evaluate a potential partner before revealing their feelings.
This is just the latest in a spate of recent studies to show how quickly and efficiently people are able to obtain information, or form judgements, about others. Last year, for example, Nick Rule and Nalini Ambady showed that observers were able to accurately judge men's sexual orientation within 50ms, and in 2006 Janine Willis and Alexander Todorov found that people judged the trustworthiness of others within 100ms.
Skyler S. Place, Peter M. Todd, Lars Penke, Jens B. Asendorpf (2009). The Ability to Judge the Romantic Interest of Others. Psychological Science, 20 (1), 22-26 DOI: 10.1111/j.1467-9280.2008.02248.x