Running around the game world sometimes characters automatically do rolls for things like history, arcana, perception etc. I have found however that some of the time when I get a successful perception roll the character will just say "that is interesting" or something similar and I will spend 10 minutes inspecting every inch of the area for what it was they discovered. I remember the old games would have a little text tooltip saying "trap detected" or something to indicate what you found. I have tried checking the log but it just says there was a successful roll.