The answer: 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.
"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 the study's first author, Janelle Seegmiller, a psychology doctoral student.
The study -- explaining why some people are susceptible to inattention...