Stall Catchers: the Schaffer-Nishimura Lab's citizen science game

Stall Catchers is the first game of EyesOnALZ, a citizen science project created by the Human Computation Institute with collaborators at Cornell, Berkeley and Princeton and with support from the BrightFocus Foundation. The game's own site describes it as an EyesOnALZ game. The game turned one year old in October 2017, and its team marked the date by naming Catchers of the year on the project blog.

The research behind it comes from the Schaffer-Nishimura Lab at Cornell University, whose work centers on optical tools for studying animal models of neurological disease. The lab's imaging shows capillaries in the brain that are clogged, so that blood no longer flows in them. These blocked vessels are called stalls. The game's site says scientists at Cornell found links between stalls and Alzheimer's disease.

Each round shows a short movie of one vessel in the brain of a living mouse. A tool called the Virtual Microscope lets the player move through layers of tissue, and the player decides whether blood is flowing or the vessel is stalled. Correct calls build a score, raise the player's level and place the player on a leaderboard, and digital badges mark achievements.

The data takes about an hour to collect, and a trained scientist needs about a week to analyze it. In 2017 the researchers described spotting a stalled vessel as a perceptual task that people handle easily and machines did not yet handle well. Spreading the review across many volunteers is the game's answer to the backlog. The game's page puts it as players doing in one hour what takes researchers one week in the lab.

Projects of this kind belong to the field of public participation in scientific research, in which volunteers collect or interpret data under the guidance of scientists. Most such projects train volunteers in the procedures, because consistent data matters more than speed alone.

Stall Catchers is available. The address stallcatchers.com loads the game's home page, with a button to join and a login for returning players. Sign-up is required so that contributions can be recorded, and the page says registration data will never be shared. A counter on the page read 181,552 catchers in November 2026.

The project around it is active too. The EyesOnALZ blog lists Catchathon events, in which groups play together, and the Human Computation Institute's site describes the institute as a nonprofit innovation center. The Schaffer-Nishimura Lab keeps its own site at snlab.bme.cornell.edu.