Count from 57 up to 75 in your head. What did that feel like to you, in your head? Describe how the process of counting goes for you. I remember reading about this in one of physicist Richard Feynman's semi-autobiographical books. For instance, for me counting is a sort of auditory process. In my head, it's like I hear myself saying the words "57, 58, 59, 60, ..." If I want to, I can visualise the numbers too, perhaps appearing one by one and disappearing, but that is not the primary or automatic sensation I have when I count silently. For some other people, a different thing happens. Some people describe "seeing" a mental image of a long number line stretching out from left to right. As they count, their visual attention moves from one number to the next on the line - or maybe the line as a whole moves to bring the next number into the centre of attention. The point is: my perception of counting in my head feels primarily auditory. For some other people, the primary sensation is a visual one. Feynman tried some experiments. He found that he could count in his head at a more-or-less consistent rate under normal circumstances. That is, he could reliably start at 1 and count up to approximately the same number (plus or minus one or two) in the space of, say, 1 minute. So, then he tried various experiments to see whether he could perform additional activities while counting in his head, and to measure the extent to which different activities would throw off his timing. For instance, he tried running up stairs while counting in his head (because exercise increases heart rate, which might affect the internal count rate). He tried various mental activities too, like reciting a poem out loud at the same time as mentally counting in his head, or drawing a picture - or writing something down - while counting in his head. Feynman described his own counting process the same way it works for me. He found that, for example, for him, running up stairs had little to no effect on the count rate. But he found it practically impossible to speak while maintaining a consistent count rate in his head. He conjectured that speaking messed with the process because when you speak you're interrupting the mental "one, two, three, four ..." that you're trying to "say" in your head. However, Feynman also carried out his experiments on other people. He found that the visual types - the ones who described seeing the numbers on a line - had no problem speaking out loud while maintaining their internal count rate. But if they had to do a visual task - like drawing or writing, that would mess things up for them. I think this is an interesting insight into the "other minds" problem we all face. Counting seems like an ordinary activity that everyone can do, and most of us probably never think about how we do it. Turns out that different people do it quite differently from how you do it. While they may look like ordinary human beings, just like you, it turns out that some of them are actually weird beings whose internal thought processes work quite differently from yours. So, how does the counting thing work for you? Let's collect some statistics in the poll.