Memory is like the old telephone game, according to researchers at Northwestern University School of Medicine. You remember when kids took turns whispering a message into the ear of the next person in line? By the time the last person spoke it out loud, the message had radically changed. It’s been altered with each retelling.

Every time you remember an event from the past, your brain networks change in ways that can alter the later recall of the event. Thus, the next time you remember it, you might recall not the original event but what you remembered the previous time. The Northwestern study is the first to show this.

“A memory is not simply an image produced by time traveling back to the original event—it can be an image that is somewhat distorted because of the prior times you remembered it,” said Donna Bridge, lead author of the study published in the Journal of Neuroscience. “Your memory of an event can grow less precise even to the point of being totally false with each retrieval.”

The reason for the distortion, Bridge said, is the fact that human memories are always adapting. Take note, lawyers and eyewitnesses.