Motor Learning Occurs in Children (but not young adults) in a Novel Nonword Production Task
B Walsh, A Smith, C Weber-Fox
In order to examine the possible effects of motor learning and phonological complexity on childrenís and adultsí speech movements, we analyzed the production of novel nonwords of increasing phonological complexity spoken by 20 9 and 10 year old children and 20 young adults (18-31 years).† We employed a trajectory variability index that captures the trial-to-trial consistency of the collective efforts of the upper lip, lower lip, and jaw to produce oral opening.† Variability indices were also computed separately for the first five and last five productions for each word by each subject to examine order effects.
For both children and adults, the variability of articulator coupling increased with increasing phonological complexity, although children were significantly more variable than adults on this measure.† In addition, children were significantly more variable on the first five productions, compared to the last five; however, the adults did not show this learning effect. Thus, the present results show that, in the absence of syntactic and semantic constraints, the stability of childrenís and adultís speech movements are impacted by phonological complexity, and that children show speech motor learning within a short time frame.