I present the results of an artificial grammar experiment arguing (i) 
that abstract foot structure exists (so prosody is hierarchical), and 
(ii) that the metrical foot may be a prosodic universal, in that 
listeners infer foot structure even when the empirical evidence for 
higher-order metrical grouping is weak. Results from Japanese-speaking 
participants provide support for analyses of Japanese phonology, 
phonetics, and morphology that rely on footing. This paper supersedes 
Ch. 4 of my dissertation (Bennett 2012).