I encountered a quiz (I forgot what’s called) on a website (I forgot also its name) to determine which of following audios does change a speaker’s voice in the middle of his narration/speech. So it requires keen hearing and delicate recognition of voice/speech characteristics (timbre, texture, intonation, accent, articulation, pacing, mood etc…). I’m have no idea if malbots could determine whosever voices will be.
And also a polka-dotted somewhat colorblind quiz to determine a number/letter formed on polka dots or sometimes scatters of randomly colored and assorted shapes.