I wonder whether they'd get different results if they used shapes rather than numbers, or by phrasing it slightly differently: 'All pyramids have red on the ba

I wonder whether they'd get different results if they used shapes rather than numbers, or by phrasing it slightly differently: 'All pyramids have red on the back, which cards do you need to turn over to verify this?' IME people tend to turn off when numbers get shoved under their noses.