Researcher Zoran Popovic' has developed a video game called Mozak (Serbo-Croatian for “brain”) for the Allen Institute for Brain Science that enlists players— research participants, actually—to trace lines over images of neurons (Wingfield, 2017). The goal: to create three-dimensional models that other researchers can use to study what happens when the nervous system goes awry, such as with Parkinson’s disease. Because there are so many variations of neurons—more than 100 million neurons in the human brain —Popovic' and his colleagues need help. They have managed to entice about 200 users to play the game daily, garnering points and attaining levels as in any video game. This work has enabled the researchers to work 10 times as fast as without the Mozak players.

a. Which method of sampling is Popovic’s team using to collect data?

b. What is the primary benefit of this method?

c. What is a possible ethical problem with this method?