If you ask members of a team to look back on a completed project and talk about how it progressed, you will get a different story from each team member. Not only will they take different perspectives, but they may remember key issues differently such as who came up with pivotal ideas, who helped save the day in work with a particular client, or even whether particular meetings or discussions ever took place.

Why do these accounts differ so strongly?

Egocentrism and self-serving biases

Even when people recall past events accurately, there is going to be some difference in the accounts that people give of the past. For one thing, people experience all of their own contributions to a project, but only hear about many of the contributions of other people. As a result, there is a general tendency for people to emphasize their contributions to a project, because those are most vividly represented in memory.

On top of that, even when you’re aware of other people’s contributions, you tend to paint yourself as the hero of your own life story. So, you typically interpret your own actions in the most charitable way and give less credit to others than they may deserve. Much of this interpretation happens at the time the events are initially experienced, and so they are baked into the memory of the event.

Schema-driven memory

It’s important to bear in mind that a core function of memory is to provide you with information you are likely to need in a particular situation. Although accurate accounts of past events are prized by modern society, they are not the central thing that memory evolved to do.

In order to be able to predict what will happen in a complex event, you have developed frameworks in memory often called schemas that help predict the sequence of events you are likely to experience and the reasons why you perform those events. When going to a doctor’s office, for example, you probably check in at the front desk, sit in the waiting room, get called back to an exam room, meet first with a nurse, then with the doctor, and then pay your bill and leave. You also know that if you fail to check in at the desk, you probably won’t get called into the office, because nobody will know you’re there.

As valuable as these schemas are for predicting the future, they influence your memory. You may misremember on which visit to the doctor that you read a particular magazine article in the waiting room. You might remember that you made an appointment for a follow-up visit when you did not, because you generally do before leaving.

You have schemas for many things that you do at work. When you think back on the past, you may use those schemas to structure your memory, which may lead you to misremember the order of events or the particular meeting in which a key idea was stated. You may give credit to a supervisor for an idea rather than their subordinate, because you expect supervisors to be more likely to push projects forward. You may also forget key details that don’t fit with your general schema about how projects work.

Memory intrusions

Memory is also dynamic. You don’t just store away a snapshot of a past event and then pull it out periodically to look at it. Every time you think about an event, you may also influence your memory for that event. Things you hear about after an event can get mixed in with your visual memories of the event itself. That is, new experiences intrude on the memory and become a part of it.

Again, it might seem strange that your memory for your history can be so malleable. In general, though, you just want to know how to react in new situations. Consider a typical situation, though. Your boss outlines a project for you to work on. Some of what you are asked to do is clear, but you are confused about other pieces. After conversations with colleagues, you have a much clearer sense about what you’re supposed to do. It would be strange for your memory to contain a record of your confusion. You would rather remember what you were asked to do along with your current understanding of the task. That will lead to a distorted view of the history of what happened, but will put you in the best possible mindset to complete the project.

When you put all this together, you may realize that it’s generally a good thing that your memory does not provide an accurate history of the past—even though it can be frustrating to get as many accounts of the history of an event as there were people who experienced it.