Here's how Facebook is automatically telling your good memories from your bad ones
It's the one that resurfaces old photos and posts in an attempt to remind you of good times gone by.
The feature doesn't always get it right. And anybody who's ever been through a bad breakup or lost a loved one can see how On This Day might dredge up memories they'd rather not recall.
On Friday, Facebook is planning to unveil a couple of new updates aimed at improving the feature.
One will automatically gather your recent photos and posts and collect them in monthly or seasonal recaps. The other will provide a little indicator when you've crossed a certain number of friends or reached a certain threshold in likes.
But more importantly - and less obviously - the social networking giant has made some changes to On This Day under the hood. The changes are intended to prevent the feature from highlighting painful memories.
I spoke to Facebook officials, including On This Day product manager Oren Hod and memory researcher Artie Konrad, about why the social network is so interested in bringing back the good times - and how they're working to shield you from the bad ones.
A gift from Facebook
"We think of [On This Day] as a small gift that we give to people on our platform," Hod said.
When you open up Facebook, the company wants to offer you a "delightful" surprise by reminding you of things like a fun outing you had with a friend, your college graduation, or a family reunion. To figure out which events or photos to highlight, Facebook uses a "pretty sophisticated algorithm" to identify the signals that can indicate which memories are good and which are bad.
Some of those signals are pretty straightforward. If you've blocked someone on Facebook, or otherwise gone through what Hod calls the "breakup flow," you probably don't want to see posts from that person. Similarly, if an event or photo involves someone who is now dead and has a memorialized account on the social network, it won't appear in On This Day.
"We don't want to resurface everything," Hod said.
From there, though, it gets more complicated. What happens when good memories go bad?
Finding good memories
There's sort of an art to sifting out good memories, said Konrad, who holds a PhD in using technology to assist memory from UC Santa Cruz. Obviously, Facebook factors in the number of likes and comments a post or photo receives, but there's more to it than that.
Over the years, Facebook has learned a lot about the memories people actually like to re-share long after they were originally posted, Konrad said. People don't really like to be reminded of meals they've had, no matter how good they were, for example. But the word "face," as in "I miss your face," is actually a strong indicator that a post or picture is a memory that someone might want to recall. So too are posts or photos that involve family members of particular users.
Still, not every post that draws a lot of interaction from a Facebook user's friends is one the user will want to see again. A medical emergency may get a lot of comments, including many from family members, but it's not something you'd likely want to relive a year or two later.
Facebook has started using its newer "reactions" feature - which allow users to react to posts they love with hearts or to those that make them sad with a sad-faced emoji - to help filter posts. Those with lots of "sad" or "angry" responses get weeded out from On This Day.
Still, Konrad said, it's not enough to rely on the algorithm alone. He speaks of "contamination sequences," an academic term for those instances when a good memory becomes a bad one. For humans, it's obvious that people wouldn't want to be reminded of such moments. But it's not so obvious to Facebook's algorithm.
"There's no way for Facebook to know that isn't a happy memory anymore," Konrad said.
That's why it's so important for Facebook to offer tools that allow users to customize the feature, he said. The algorithm can do a better job of filtering out painful memories, but only after getting some human guidance that lets it know to avoid certain people or topics. Users will now be able to to block certain dates or people from appearing in their flashbacks.
In the meantime, Hod wants users to know that Facebook is reading its feedback and working to further minimize the number of bad memories that On This Day might dredge up. Just keep filing those feedback reports, he said.
"We always deal with it, even if it takes some time," he said.