Differences in the learnability of linguistic patterns may be crucial in de
ciding among alternative learning models. This paper compares the ability o
f English speakers (Experiment 1) and portuguese speakers (Experiment 2) to
learn two complex rhythm patterns observed in languages with primary word
stress. Subjects were familiarized with one of two rhythms during a discrim
ination task, followed by a recognition task which tested whether knowledge
of the rhythm generalized to novel stimuli. The main findings were: (I)spe
akers trained on the cross-linguistically less common rhythm distinguished
between novel stimuli which did or did not conform to their training rhythm
, while speakers trained on the more common rhythm did not; (2) English spe
akers wen biased more strongly than Portuguese speakers against final stres
s; and (3) melodies that an on a boundary between rhythm categories were tr
eated as less prototypical than other members of the same rhythm category.
The results demonstrate that knowledge of complex linguistic rhythms can be
generalized after very little training, and that the less common rhythm is
easier to learn even though it seems more complex. The results are compare
d with general-purpose exemplar-based learning models as well as abstract l
inguistic theories of word stress acquisition.