If memories were fixed like videotape recordings, then imagining a new situation would be challenging. For instance, you can picture yourself arriving by double-decker bus at a tropical beach for the wedding of Johnny Depp to your best friend next week. To do so you need to do the equivalent of finding your personally recorded memories of sitting on buses and visiting your best friend, before ordering clips from the mind's archive of films starring Johnny Depp and TV programmes featuring tropical beach weddings -- memories which could be decades apart. Then you splice all these elements together to create the scene. Cognitively it sounds like hard work, but the flexibility of our memories makes it relatively easy to meld these memories together to invent a scene that we've never witnessed before.
Turns out there's a benefit for memory being so pliable: imagination. Claudia Hammond explores: