The period of time when the facial expression occurred was time-aligned with the subset of words (the sequence of signs performed on the hands) for the appropriate syntactic domain; the phrase-beginning and phraseending was aligned with the performance of the facial expression.
the difference in appearance between our animation stimuli was subtle: The only portion of the animations that differed between the three conditions (neutral, centroid, and latent-trace) was the face and the head movements during the span of time when the syntactic facial expression should occur (e.g., during the Wh-question).