Researchers at the University of Utah have determined that having a high working memory capacity is not an indication of one ability to focus deeply on a current task but a strong capability to shift attention to another task when it is needed. Working memory capacity determines a person's degree of inattention blindness. Less memory, more blindness-even to gorillas in a room.

Explaining why some people are more prone to inattention blindness than others, Janelle Seegmiller with two other faculty members will be publishing their results in the May issue of The Journal of Experimental Psychology: Learning, Memory and Cognition.

"Inattention blindness" is what researchers call the phenomenon that leaves drivers on cell phones prone to traffic accidents and makes a gorilla invisible to viewers of a famous video. Seegmiller's group used a video made famous by earlier "inattention blindness" research featured in the 2010 book "The Invisible Gorilla," by Christopher Chabris, a psychologist at Union College in Schenectady, N.Y., and Daniel Simons, a psychologist at the University of Illinois at Urbana-Champaign.

The video depicts six actors passing a basketball where viewers are asked to count the number of passes. People are so focused on counting fail to see a person in a gorilla suit walk across the screen and even stop to thump his chest, before walking off.

Seegmiller, Watson and Strayer did a new version of the older experiments, designed to determine the reason some people see the gorilla and others miss it.

"Because people are different in how well they can focus their attention, this may influence whether you'll see something you're not expecting, in this case, a person in a gorilla suit walking across the computer screen," says Seegmiller. She explains that people who fail to see something right in front of them while they are focusing on something else have lower "working memory capacity" - a measure of "attentional control," or the ability to focus attention when and where needed, and on more than one thing at a time.

Working memory capacity "is how much you can process in your working memory at once," Seegmiller says. "Working memory is the stuff you are dealing with right at that moment, like trying to solve a math problem or remember your grocery list. It's not long-term memory like remembering facts, dates and stuff you learned in school."

The researchers studied working memory capacity because it "is a way that we measure how some people can be better than other people at focusing their attention on what they're supposed to," she adds.