If I remember I'll ask a guy who knows more about the psychology of rhythm than most others in Germany.

I know only that much from what he once told me: it is close to impossible for participants in studies not to fall into a rhythm (the task could be, e.g., finger tapping as uniformely in time and strength as possible). The measures are both the intervals between tapping and the strength/loudness of tapping. Usually each fourth beat was prominent in same way (I forgot if the interval before this beat was longer or shorter than the other intervals). Eight is four times two. But beyond this (superficial?) similarity I have nothing to offer.

Wolfgang