Our abilities to see things that appear fleetingly or in cluttered environments or outside our focus of attention are all determined by a single perceptual capacity trait that varies among people, a new study suggests. Researchers say these findings could one day help scientifically predict an individual's performance in jobs that rely on strong observational skills.

Psychologists Joshua Eayrs and Nilli Lavie of University College London tested participants on a range of visual tasks. One measured how well people could estimate the number of objects appearing on a screen for a tenth of a second—a capacity known as subitizing. Others measured the ability to notice small differences between two real-world scenes; to detect a change at a screen's edge while focusing on the center; and to track multiple moving dots among static ones.

People who excelled at subitizing also tended to perform better on the other tasks, the team reported online in March in the Journal of Experimental Psychology: Human Perception and Performance. “This is the first study to establish a perceptual capacity trait,” Lavie says. “It's an important ability, which [determines] how much information you can process when there's a lot of it around you.”

Theoretically, performance on any task that relies on this perceptual ability (not just those studied) could predict performance on any other. Lavie's team also demonstrated that perceptual capacity is distinct from general cognitive ability and ruled out other possible factors such as varying levels of motivation.

The findings are interesting and plausible—but they are preliminary and need to be independently replicated in larger samples, says psychologist Matt Meier of Western Carolina University, who was not involved in the study.

The scientists say their work could help develop tests to screen potential employees for safety-critical jobs in demanding visual environments, such as air-traffic controllers, security guards or military personnel. Lavie says her team is already investigating whether measuring perceptual capacity can predict actual job performance in such roles.