Page:American Journal of Psychology Volume 21.djvu/44

34 161. In fact it was this change which introduced sufficient delay to make it possible for the young Song Sparrow to open the door. She did not, so far as could be seen, do so in an imitative way. Later there were a few movements which were similar to those of the White-throated Sparrow, but they did not have to do with the right part of the box.