Learning and Memory

Memories may spontaneously decay over time, but the main cause of forgetting appears to be interference from other memories. Many apparently lost memories are still in storage, but preceding and following events can both make it harder to find them (proactive and retroactive interference), especially if the memories are similar. Retrieval is more likely insofar as our current environment—including our emotions—resembles the original; stimuli that were present then can act as retrieval cues, reactivating associated memories. If a retrieval cue is associated with many memories, however, it is less likely to activate any one of them (cue overload). While a memory is being activated, it may automatically inhibit competing memories (retrieval-induced forgetting), and we can also suppress memories deliberately. If we are only able to activate fragments of a memory, we may unconsciously reconstruct the original, and research on the misinformation effect, source confusion, and reality monitoring has shown how flawed this reconstruction can be, in some cases leading us to confidently recall events that never occurred. The combination of constructive processes during perception and reconstruction during retrieval mean that our memories are more like rough sketches of events than detailed photographs.