If an object isn't to scale with its surroundings, it's easier to overlook, according to a study published last week in the journal Current Biology. Participants were asked to search an image for a particular object. Sometimes the object was missing, sometimes it was normal-sized, and sometimes it was four times larger than normal. Participants were 13% more likely to miss the object when it was larger than expected.

Why it matters: It's part of a larger body of work showing expectations can influence how we perceive the world around us. Similar phenomena explain why sometimes objects we were looking for were in front of us the whole time, just out-of-context.

Go Deeper: The New York Times features examples of this illusion, and others, at work.