Maybe that's the difference: human beings think abstractly and chimps don't? So we remember the abstract, but they simply retain images? If you think about it,

Maybe that's the difference: human beings think abstractly and chimps don't? So we remember the abstract, but they simply retain images? If you think about it, there's nothing especially mysterious about good memory per se if we view it as something like writing things down or a recording. You have to put effort into destroying the memory. Degradation is comparatively slow. So to judge how good (or conversely, bad) memory is, you have to determine what the goal is and the "architecture" implementing it. Recalling recent images that are destroyed shortly after being recorded vs. a mind map of conceptual relations, for example.