A decade ago, we lived in an apartment tower in Jersey City overlooking the Hudson River. We had a panoramic view of Manhattan—and of planes flying in and out of the nearby airports. After several years there, I got used to rolling my eyes as my husband pontificated on the make, or approach, of various pieces of equipment as they roared by our large windows.

On 9/11, as we sat down to breakfast, my husband suddenly said: “Wow, that plane is flying awfully low.” That got my attention, wondering if he could really have spotted something amiss. But he soon left for work, only to return a few minutes later. A crowd had greeted his arrival at the train station. The clustered commuters, he determined, were all looking at the aftermath of the first plane strike. As the drama unfolded, we took our five-month-old out of daycare and drove to my in-laws, who resided much farther away from the action.

Like nearly everyone else who lived through that day, I feel I remember it clearly, even though data shows that people’s recollections of 9/11 have, in fact, significantly degraded with time (see How Accurate Are Memories of 9/11?). Recent research published in Psychological Science suggests that some of that distortion is social. My conversations with others about the event—the retelling of my own experience, for example—have etched particular parts of 9/11 in my mind at the expense of other facts and memories.

This latest work is an elaboration of a revelation about human memory psychologists made the mid-1990s. Back then scientists discovered a phenomenon they called retrieval induced forgetting in which a person’s attempt to recall one piece of information causes him or her to forget closely related memories. This type of forgetting explains why repeatedly taking a better route to a friend’s house makes the old route fade in your mind, but has no impact on your memory for, say, how to get to your office.

That earlier work applied largely to people’s independent efforts to practice, read or recite material. Yet much of what we do during the day involves interacting with others. So a few years ago, psychologist William Hirst and his colleagues at New School for Social Research in New York City decided to study forgetting in a social context. In their first experiments, they found that one person’s selective recounting of a written story caused both that person and a listener to forget related, unstated information from the story (which they both read) more than unrelated material. Then Hirst, along with Alin Coman, now at the University of Pittsburgh, and David Manier at City University of New York, tested the idea in a more lifelike setting by investigating the effect of conversation on 9/11 memories.

The team asked 22 people who lived in the New York City area on September 11, 2001, to fill out a questionnaire about what they remembered about that day. Then pairs of participants (who did not know each other) discussed their personal recollections of the attack. If either conversant left out specific relevant details from the questionnaire, Hirst, Coman and Manier found, both of them had trouble remembering the omitted items later on. Memories that were closely related to the ones mentioned in the conversation became the most difficult for both the speaker and the listener to access. For instance, if one person shared that she woke up at 8 a.m. that day, but neither she nor her conversation partner then mentioned the time at which they heard about the attack, they each had trouble recalling that detail later. Over multiple conversations, Hirst speculates, that neglected information could become forgotten.

And as people repeatedly talk to each other about shared experiences such as 9/11, as I have, they may trigger a kind of collective forgetting that shapes joint memories. “What people forget in common is also a function of what they remember in common,” Coman says. “If a group of people forget the same things, that will increase the amount of shared information in their memories.” Such morphing of memory through conversation helps forge a collective identity in society by creating a common view of the past, Hirst believes. Other communication practices such as those propagated through the media are also likely to influence both individual and collective memory.

I now wonder how listening to other people’s 9/11 stories might have shaped my own. And even though I now know my remembrances of that day are probably warped, I am sticking to my story, because it is truly the only one I have. I don't mind the fact that my brain does not accurately record all the events of the past as a digital camera might. The notion that my life, including all the people who have enriched it, has distorted my recollection of events is even sort of appealing. I favor the metaphor of my mind as a tapestry stitched together by arguably useless chitchat. In fact, knowing that I enlist others to remake my memories of parties, adventures, romantic breakups, car accidents—and major disasters, doesn’t bother me at all.

Ingfei Chen contributed to this blog.