required a little more than two months of irregular and occasional practice and experimenting for R. to learn to turn a door-knob and pull a door open so he could get out of the room. I first tried to teach him to turn the knob and open the door in the last week of the twenty-fifth month by taking hold of his hand and putting it through the motion of turning the knob and opening the door. But the child could not get the idea, he didn't understand what was to be done, although he would pull and tug at the knob as, indeed, he had for several months before.
A few notes from the record for the twenty-sixth and twenty-seventh months will be transcribed to indicate the general order of progress in learning to open a door.
Twenty-sixth month (last week).—The child could not turn a knob either to open or shut a door; he had not associated turning the knob with latching or unlatching the door; i. e., he did not understand the use of the knob.
Twenty-seventh month (second week).—The child tugs at the door-knob, pulling, turning, twisting, and succeeds sometimes in getting the door open. He understands now that tugging at the door-knob is followed by the door's opening. But he does not yet make the necessary combination of movements to get the door open. (Third week) The child is able to close a door and latch it after considerable tugging and turning.
