Can we infer someone's cultural group from their laugher, even when we do not know what they are laughing at? And what kind of laughter do we find most positive? A new study by researchers from the University of Amsterdam with international colleagues shows that our laughter gives us away. The study included Dutch and Japanese producers of laughter and listeners. Listeners could detect whether a laughing person is from their own or another cultural group by only hearing a brief laughter segment. Spontaneous laughter was rated as most positive by both groups. The results are now published in a special issue on voice modulation of Philosophical Transactions B.