Rhythmic properties of spoken language such as
metrical stress, that is, the alternation of strong and
weak syllables, are important in speech recognition of
stress-timed languages such as Dutch and English. Nineteen
subjects listened passively to or discriminated actively
between sequences of bisyllabic Dutch words, which started
with either a weak or a strong syllable. Weak-initial words,
which constitute 12% of the Dutch lexicon, evoked more
negativity than strong-initial words in the interval between
P2 and N400 components of the auditory event-related potential.
This negativity was denoted as N325. The N325 was larger
during stress discrimination than during passive listening.
N325 was also larger when a weak-initial word followed
a sequence of strong-initial words than when it followed
words with the same stress pattern. The latter difference
was larger for listeners who performed well on stress discrimination.
It was concluded that the N325 is probably a manifestation
of the extraction of metrical stress from the acoustic
signal and its transformation into task requirements.