Fig. 7.

Postdeafening changes in chunk duration (in milliseconds) in one young adult and one old adult. Thefirstdatapoint in each series is the presurgery chunk duration; thus all pointsare shifted by 1 week. In these examples, the young bird had three chunks; the older bird had four. Notice that chunk duration changed more in the younger than in the older adult and that when changes occurred, they could be in the direction of making a chunk longer or shorter. The slope of regression lines fitted to each bird's performance during the first 8 postoperative weeks was calculated and used to produce the next figure (see Fig. 8).