CrowdCamp Report: Reconstructing Memories with the Crowd

From cave paintings to diaries to digital videos, people have always created memory aids that allow them to recall information and share it with others. How can the collective memories of many people be combined to improve collective recovery. For example, the layout of a community gathering place with sentimental or historical value could be recovered, or accidents and crimes may be explained using information that appeared trivial at first but actually has great importance.

Our CrowdCamp team set out to determine what some of the challenges and potential methods were for reconstructing places or things from the partial memories of many people.

Case Studies

We began by attempting to reconstruct common memories such as the layout of a Monopoly board. Figure 2 below shows our individual and collective attempts at this task. We found some facts that one group member recalled helped resurface related memories in other members. However, working together also introduced ‘groupthink’, where a false memory from one person corrupted the group’s final model. This is a known problem, and it is one reason why police prefer to interview witnesses separately.

Figure 1. Our reconstruction of a Monopoly board (left), compared to the true version (right).

The Effect of Meaningful Content on Memory

Next, we tried to see how information type changes the process. It’s well documented that people’s minds summarize information for better recollection. We tried 3 cases:

  • No meaning: Memorize a Sudoku puzzle (table of ordered numbers)
  • Some meaning: Memorize a set of about 30 random objects
  • Meaningful scene: Memorize a living room scene

For each, we first tried to memorize parts of the scene without coordination, then with predefined roles, e.g., different members were told to remember disjoint aspects or parts. In both cases we first wrote down what we remembered, then merged our results. Coordinated roles increased both recall and precision. Recall increased because the set of items we remembered individually was more distinct, meaning we did not redundantly memorize the same things. Precision increased because the more narrow task additional focused our attention by removing extra distractors.

Opportunities and Challenges

In some settings, prior domain knowledge allows people to organize for increased collective memory. One theme is that diversity aids in reconstruction. For example, one person may remember colors well while another may be color-blind but have a good spatial memory. Even outsiders who have no connection with the memory may be able to help.  For example, in Figure 2 below, a paid oDesk worker helps us remember our stressful first-day presentation at CrowdCamp by creating an illustration based on notes and images we provided.

An image depicting 4 presenters crying and one girl sitting at a desk in the background.

Figure 2. An oDesk worker’s rendition (left) of our stressful CrowdCamp presentation based on our notes and sketch we provided (above).

We identified three main challenges to reconstructing memories:

  • Groups, especially those containing members with strong personalities, are subject to groupthink, which can introduce errors.
  • Because some aspects of a scene are more salient, people’s memories often overlap significantly.
  • In unbounded settings, people’s accuracy decreases, likely due to an overwhelming amount of information

One consistent property was that we tended to remember nearly all of the information we could recall in total in the first few seconds or minutes, depending on the size of the task. After that, significant gains were only seen when one person’s idea jogged the memory of another.

Future Directions

We believe this work has great potential to introduce a more structured way to recreate memories using groups of people of all sizes, while avoiding problems encountered with naïve solutions. For example, approaches that mix individual recollection early on with later collaboration, while using parallel subsets of workers to minimize groupthink, could improve the way we recover knowledge in settings ranging from historical documentation to crime scenes.

What other ideas or references for recovering ideas can you think of? Anything we missed? We’d love to hear about it!

Adam Kalai, Microsoft Research

Walter S. Lasecki, University of Rochester / Carnegie Mellon University
Greg Little, digital monk
Kyle I. Murray, MIT CSAIL