The following files show the process of speech categorization developing over the course of several hundred milliseconds in each of the three age groups we studies (7-8 y.o., 12-13 y.o., and 17-18 y.o.).
To make each movie, we converted the fixations to a bias measure (e.g., looks to /p/ - looks to /b/) and computed this at each 20 msec time slice for each step of the continuum. This can be seen as analagous to a traditional 2AFC phoneme categorization, though target to a specific time post-stimulus onset. We adjusted the steps for each participants' own category boundary to isolate variation in the slope specifically.
Two movies are provided, one for the b/p and one for the sh/s continuum.