Time-driven effects on parsing during reading

The phonological trace of perceived words starts fading away in short-term memory after a few seconds. Spoken utterances are usually 2–3 s long, possibly to allow the listener to parse the words into coherent prosodic phrases while they still have a clear representation. Results from this brain potential study suggest that even during silent reading, words are organized into 2–3 s long ‘implicit’ prosodic phrases. Participants read the same sentences word by word at different presentation rates. Clause-final words occurring at multiples of 2–3 s from sentence onset yielded increased positivity, irrespective of presentation rate. The effect was interpreted as a closure positive shift (CPS), reflecting insertion of implicit prosodic phrase boundaries every 2–3 s. Additionally, in participants with low working memory span, clauses over 3 s long produced a negativity, possibly indicating increased working memory load.

► A CPS was found every 2.7 s measured from sentence onset during reading.
► Implicit prosodic phrases seem to have an optimal duration between 2 and 3 s.
► The optimal duration for implicit prosodic phrases mirrors that of overt phrases.
► The low working memory group showed a left negativity for phrases over 3 s long.