And I'm wondering whether this has something to do with the rhythm of language... The heart-beat would give the baseline but language would create different patterns...??
Last year the lead author was a post-doc in the lab I work in and we discussed it... Nori and colleagues are certainly interested in how prosodic differences between languages may affect the priors. But it's probably not going to be a very straightforward story... the rhythms in languages are considerably more complex than the ones they find people have a preference for.
Some of our preliminary research about speech rhythm did get to the Current Biology paper. Figure 6 in the paper uses the method to study prosody of 5 sentences in English. (N.J)