July 12, 2010 at 4:10 PM ETEven if you're expecting the unexpected, you're still going to miss some things, suggests a new study. In some cases, those things will be wearing gorilla suits.A well-known study in the late '90s asked participants to watch a video and count the number of times a group of students -- some dressed in white, some in black -- passed a basketball back and forth. In the middle of the video, a person dressed in a gorilla suit runs into the middle of the game, and then sticks around for a bit while he waves his hairy arms and beats his chest. The funny thing? About half of those who watched the video didn't notice it. It's an example of what's called "inattentional blindness." That's a term that describes our inability to notice something that's happening right in front of us, usually because it's unexpected, or because our attention is focused elsewhere.The new study, published this month in the journal i-Perception, builds on the original experiment: Say the participants have heard of the original study, and know to look for the gorilla. Would they notice other unexpected events introduced in the short video? Would you? Check it out here.As University of Illinois psychology professor Dan Simons reminds us, "Looking isn't the same as seeing." Simons co-authored this study and the original study with Union College psychology professor Christopher Chabris. The two have published a book called "The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us," in which they tackle everyday illusions. One example you're not going to like: Talking on your cell phone as you drive really does reduce your awareness of obvious dangers on the road, even if you're using a hands-free device.Can you think of a time -- while driving, watching a sports event, or anything else -- when you failed to notice something that was happening right in front of you? Tell us about it in the comments.To read more Body Odd posts, click here. You can also find us on Twitter and on Facebook.