Alternating items

A block has a pool of trials and a number of presentations. Those are not the same number.

The pool is the list on the Trials tab: each row is a stimulus keyed left or right. Number of presentations is how many times the block runs an item during administration. Defaults: 20 on blocks 4 and 7, 10 on the others. You can edit that. Adding a trial does not change it. Deleting a trial does not change it.

Administration draws from the pool. If the pool is shorter than the presentation count, items repeat. If it is longer, some items in the pool will not appear in that sitting. Write the pool you mean, then set the count you mean. Do not sort the sequence grid — column-header sort is off so you cannot scramble instruction order by accident.