Flaws in memory can arise at different points in the process, explained Daniel Schacter of Harvard University. When someone first records a memory, the viewer incorporates his or her own reactions and inferences about the event. As a result, the viewer can color or distort the memory from the very beginning.

How unreliable is our memory?

Some studies conclude that memory is extremely accurate, whereas others conclude that it is not only faulty but utterly unreliable. ... While, on average, they recalled only 15 or 22 percent of the events that they had experienced, the memories they did recall were, on average, 93 or 94 percent correct.

How much of our memory is false?

Observers correctly identified 60% of false memories, and 53% of true memories – with 50% representing chance. This study was the inspiration for the present research.