Cryptomnesia is the phenomenon in which you claim someone’s ideas as your own. It is related to source amnesia, which is forgetting the source of a piece of information. These forms of amnesia arise because we use two different kinds of memory - semantic memory and autobiographical memory. When we listen to someone else speaking, we record the content of what they are saying in our semantic memory. This gets linked to a whole host of other things we know about that subject. Which is why we tend to remember it better. The fact that so-and-so said it is recorded in autobiographical memory, and is more easily forgotten. In a group of people, we are more likely to commit cryptomnesia to the person speaking just before us. That’s because we are thinking about the topic as they are speaking, preparing for what we are about to say, and their thoughts get wrapped up with our own thoughts. This is perhaps related to the phenomenon of neuroplasticity, and the idea that “neurons that fire together, wire together.” --- **Source** Draaisma, D. Forgetting: Myths, Perils and Compensations. New Haven [Connecticut] : London: Yale University Press, 2015.