Forget the traditional question: "Why do we remember the past?". It's a more intriguing question to ask: "Why do we share our memories of the past?". Often overlooked in discussions of memory's evolutionary purpose is the act of sharing memories with others. This activity is surprisingly common, with research revealing that a significant chunk of our daily communication involves sharing memories.
Take gossip, that infamous exchange of information about others' past actions. Studies across diverse groups, from the !Kung Bushmen in Africa to university students in London, show its pervasiveness. Analyses of everyday conversations suggest that a hefty portion of what is talked about, up to two-thirds, revolves around discussing others' actions. Interestingly, these conversations often focus on the "juicy" stuff, like a student's forbidden romance, rather than mundane details like oversleeping. The focus on social transgressions might hold a key to understanding why we remember the way we do.
Sharing memories and observations helps people gain valuable insight into others' behavior. This, in turn, is a crucial piece of the puzzle for predicting how others will act or who to collaborate with.
Research suggests that successful cooperation relies on individuals making informed choices about future interactions based on past behavior. In these "reputation-based" models, individuals with a history of cooperation thrive, while those known for cheating are shunned.
Given this framework, I propose that episodic memory may have evolved specifically to facilitate the sharing of information about past actions. By swapping memories, individuals can make smarter partner choices, promoting cooperation and minimizing the risks associated with interacting with untrustworthy individuals. If this is true, then episodic memory might have played a significant role in the evolution of human cooperation as we know it.
Humans rely heavily on working together for survival and well-being. While cooperation brings long-term benefits, there's always the temptation to cheat in the short run. This means being careful about who we choose to collaborate with. Scientists believe that a key driver of human evolution was the growing importance of cooperation, which put pressure on us to pick good partners and avoid cheaters. We need to remember those who took advantage of us in the past to avoid being fooled again, but also remember those who were helpful and could be counted on in the future. On this picture, the ability to learn from past social interactions would have been incredibly valuable for our ancestors.
We learn about others' past actions in various ways, both by directly observing them and through the stories we hear from others. The more time we spend with someone, the deeper understanding we have of their personality and behavior. However, direct experience is limited. We can't be with everyone we want to understand all the time. There will always be gaps in our direct knowledge of others. We rely on the experiences of our friends and acquaintances to fill these gaps.
In this way, sharing memories is a social shortcut to learning, offering big rewards with little effort. Telling stories about what others have done extends our knowledge, allowing us to learn valuable lessons about others' behavior. Learning about others who may cheat or violate social norms gives us the benefits of this knowledge without the risks or downsides of firsthand experience.
Imagine someone witnessing an event and then telling others who weren't there about it. This creates a "replay" of the experience, allowing listeners to engage in a kind of "post-game analysis," like sports commentators dissecting a play. Through this collaborative storytelling, people can break down the event together, reviewing and discussing it as a group. This benefits not only the listeners, but the witness too — the discussion offers critical context and interpretation that provides richer understanding than was available from the observation alone.
For example, a shared memory can be used to assess whether someone's behavior fit the social expectations of the situation. To understand why someone did what they did, listeners might try to guess their mental state. Imagining different scenarios, where the person acted differently, can be especially helpful. By comparing the observed behavior to what "should have happened," everyone can make a more nuanced judgment.
Memory sharing offers a way to assess others, creating collectively-formed mental profiles for members of the group. These profiles, in turn, contribute to each person's overall reputation within the social circle.
Sharing memories acts as a powerful tool for fostering cooperation in two key ways. First, it's a cost-effective way to learn about others. By swapping stories about past actions, people gain insights into how others behave, including things they might not have witnessed themselves. This broader knowledge helps one to choose collaborators wisely, and avoid those with a history of cheating or selfishness. Second, memory sharing incentivizes cooperation through reputation maintenance. Actions toward one person are likely to become known to many. The consequences of both selfish and generous acts extend beyond those directly involved.
This post delves into key ideas presented in a recent article published in Synthese. For a deeper dive, check it out!