Another simple feature that makes it at least very hard (possibly impossible, not sure) to proceed in an experiment with a device without a physical keyboard is to just include a ‘press space to continue’ step, using newKey(). Without a text input field, there generally is no straightforward way (if any, haven’t found one) to bring up the virtual keyboard on a phone or iPad, which means you cannot continue. (I learned this by accident in a recent study where I was leaving tablet use as an option on Prolific, and had lots of people falter precisely for this reason.) Thinking on it, I wonder whether self-paced reading would work on devices without a keyboard to begin with – is there any way to proceed within a sentence without pressing a keyboard key?