Click Edit in the top left corner of the construct (Figure 2). To save your changes, click Save in the bottom right corner of the editor to save your changes.
Figure 2. Open construct editor
Adding a key
In edit mode, click Add key in the key table, and then click Add when you're done.
Removing a key
In edit mode, click Delete on the key row you wish to remove.
WARNING: Deleting a key will also delete any trials rules related to that key.
Randomizing key values
If the keyboard response is on the trials timeline, key values can be randomized from those present. In edit mode, when two or more keys are present, you can randomize their values by selecting:
For example, if we have two keys allocated where 'z' = true and 'm' = false, the truth values can be randomly assigned across 'z' and 'm'. Randomization is consistent across all trials, and can be made consistent across multiple trial blocks via block counterbalancing if the keyboard response is a clone.
In edit mode, the following properties can be set via the timing table:
Fixed: start time will be measured from the beginning of the trials timeline.
Offset from previous item: start time will be measured from the end of the previous item on the trials timeline. If there is no previous item, or the timeout of the previous item is set to nil(infinite), then start time will be measured from the beginning of the trial.
Start time (ms): when to initiate construct.
Fixed: duration will be a fixed time period.
Random: duration will be a random time period bound by minimum and maximum values.
Factor: duration will be a randomly chosen level from the factor selected.
Level: duration will be set to the value of the chosen level.