Listen for nearby voice reactions first since that's the clearest tell. Within 2.5m distance, watch how the ghost responds when anyone talks - a yokai gets notably more active and might even start hunting at 80% sanity if you chat close by. Really important: it only hears voices and electronics right next to it, so test by talking at different distances.

If you're getting random ghost events after speaking nearby, plus clear spirit box responses when you're close, that's a strong sign. Just remember these are way more dangerous when provoked by voices, so keep quiet near the ghost room and coordinate with your team to test reactions safely. A good tip is to have one person talk while others watch for immediate activity spikes, door slams or hunting attempts.