Apple researchers designed two open-ended probes using a Wizard of Oz technique to let people train personalized machine learning systems on phenomena they define themselves.

In a week-long study, they identified four sites where ontological boundaries were negotiated: the boundaries of a phenomenon, the subject as part of relations, what counts as signal versus noise, and the objectivity of data.

The paper offers starting points for supporting boundary negotiation through design and discusses open-ended probes as a method for ontological design.