Ironically, the psychology concept that I will remember in five years is the concept of false memories. Oftentimes in the media, there are news reports on controversial trials in which star witnesses are called upon to testify as to what they remember about the crime. Before taking psychology, I used to believe these witnesses for the most part because their memories were extraordinarily vivid. After witnessing a crime, it seemed like witnesses couldn't forget those memories because of their sensational nature. But as it turns out, those vivid flashbulb memories were like any other memory in that they also could be wrong. Despite the level of detail recalled, memory reports showed that with time, distortions pervaded these recollections in a phenomenon called the phantom flashbulb memory.
Furthermore, the memory research completed by Elizabeth Loftus further proved that memories are unreliable as completely false memories could be planted. In particular, the experiment involving a photoshopped Bugs Bunny at Disneyland was particularly interesting. Despite the fact that Bugs Bunny isn't a Disney character at all, participants in the study "recalled" blatantly false details of their own experiences of meeting Bugs at Disneyland. One participant, in particular, even seemed to recalled squeezing Bugs' tail, demonstrating the incredible nature of implanted memories.
Overall, psychology has taught me to not regard memory as the absolute truth. As the Salvador Dali painting entitled "The Persistence of Memory" shows, with time, memory isn't quite as persistent as we once thought.