The science of remembering

Forgetting is normal. Losing the relationship isn't.

You meet someone, you have a great conversation, and a week later the details are gone. That isn't a character flaw. It's how memory works, and it has been measured for more than 140 years.

The forgetting curve

In 1885 the German psychologist Hermann Ebbinghaus published the first careful experiments on memory. He memorized lists of meaningless syllables, waited a set time, then measured how much effort he saved when he relearned them. The less he had forgotten, the more he saved.

0%20%40%60%58.2%20 min44.2%1 hr35.8%9 hr33.7%1 day27.8%2 days25.4%6 days21.1%31 days Time since learning (log scale)
Ebbinghaus's results: the share of the original effort he saved when relearning, at each delay. Most of the loss happens in the first hours. After a day the curve flattens out. Source: Ebbinghaus (1885).

The pattern is steep, then slow. Twenty minutes after learning, he saved about 58% of the effort. After one day, about 34%. After a month, only about 21%: relearning took nearly as much work as learning it the first time.

In 2015, researchers at the University of Amsterdam repeated his experiment and found a very similar curve.

What helps: spaced review

Ebbinghaus also found that repetitions spread over several days work better than the same repetitions crammed together. Later researchers built on that idea. Paul Pimsleur's language courses (1967), Thomas Landauer and Robert Bjork's 1978 study of learning people's names with expanding practice, and today's flashcard apps all use the same principle: review often at first, while memory is fading fastest, then let the gaps grow.

Bring a memory back just as it starts to fade, and it lasts longer each time.

How Syndeya puts it to work

When you save someone, Syndeya keeps when and where you met, what you talked about, and anything you promised. Then it brings that person back to you on an expanding schedule: the morning after you meet, then on days 3, 7, 14 and 30. After that come check-ins at 60, 90, 180 and 365 days for anyone you haven't been in touch with.

FOLLOW-UPSCHECK-INS Day 1Day 3Day 7Day 14Day 30Day 60Day 90Day 180Day 365Each gap is longer than the one before
Follow-ups come at your chosen morning time. Each one carries the context, so you can read it on your lock screen or have it read to you.

A name alone is hard to recall. Remembering where you met, what they said and what you offered gives your memory something to hold on to. That's why every Syndeya reminder brings the context back with the name.

Ebbinghaus studied nonsense syllables, not people. Meaningful details tend to fade more slowly, but the shape of the curve, fast at first and slow later, is the reason Syndeya reminds you most in the first week.

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Sources

  1. Ebbinghaus, H. (1885). Über das Gedächtnis. English translation: Memory: A Contribution to Experimental Psychology (1913). Available at Classics in the History of Psychology.
  2. Murre, J. M. J., & Dros, J. (2015). Replication and analysis of Ebbinghaus' forgetting curve. PLOS ONE, 10(7), e0120644.
  3. Pimsleur, P. (1967). A memory schedule. The Modern Language Journal, 51(2), 73–75.
  4. Landauer, T. K., & Bjork, R. A. (1978). Optimum rehearsal patterns and name learning. In M. M. Gruneberg, P. E. Morris & R. N. Sykes (Eds.), Practical Aspects of Memory (pp. 625–632). Academic Press.