The example experiment contained the following lines:
okButton = 0 0 0 0 "" ""
This means that that experiment did not have an OK button. To add an OK button in the lower right corner of the screen, you do something like
okButton = 0.8 0.95 0.05 0.15 "OK" ""
If you supply a right edge (here 0.95) that is greater than the left edge (here 0.8), Praat will know that you want to show an OK button.
The behaviour of the experiment changes appreciably if you include an OK button. If you do not include an OK button, Praat will present the next stimulus as soon as the participant has clicked a response category (and a goodness category, if there are such). If you do include an OK button, it will become visible to the participant as soon as she has chosen a response category (and a goodness category, if there are such). The participant can then click the OK button, but she can also choose to click the response (and goodness buttons) a bit more first.
The OK button seems to be useful only if there is also a replay button, or if the response categories are sounds (see ExperimentMFC 6. Responses are sounds).
To assign a keyboard shortcut (here, the space bar) to the OK button, do something like
okButton = 0.8 0.95 0.05 0.15 "OK" " "
© ppgb, December 5, 2005