The next time you’re struggling to remember exactly where you left your keys, parked your car or put down your glasses, don’t necessarily give up on your memory completely. Previous research has shown that, if people are shown a large number of objects, they are very good at subsequently remembering which objects they have seen. A new study suggests that people are also surprisingly good at knowing where and when they saw those objects. When shown objects on a 7-by-7 grid, many observers could recall the location of over 100 items, choosing the right location or a cell right next to the correct one. A series of three experiments conducted by investigators from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, illustrate that people have a “spatial massive memory” (SMM) for where objects are located and a “temporal massive memory” (TMM) for…