Experiment Layout

Now, if we look closely at the sequences to see what will be displayed and how many times we will see that what we have so far is not quite right! Currently we are displaying the SEQUENCE once and the RECORDING_SEQUENCE four times. This means we will not see the DRIFT_CORRECT every trial, only for the first one!
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What we really want is for SEQUENCE to take place for as many trials that exist so that we see the DRIFT_CORRECT every trial. But if we change the SEQUENCE to iterate 4 times, the RECORDING_SEQUENCE will then take place 16 times! This is because the SEQUENCE contains the RECORDING_SEQUENCE which also occurs four times. In other words, for each SEQUENCE it will run a RECORDING_SEQUENCE which contains 4 trials. If the SEQUENCE occurs 4 times it will run 4×4 RECORDING_SEQUENCEs.

What this means is that we need to change the SEQUENCE to occur four times and the RECORDING_SEQUENCE to occur only once. There’s a diagram below sketching this out.
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But there’s a problem. If the Data Source is attached to a sequence, you cannot change the Iteration Count for that sequence. It will only show the Iteration Count as the number of trials in the datasource attached to that sequence!

This means we need to move our Data Source from the RECORDING_SEQUENCE layer into the SEQUENCE layer. This might seem crazy and annoying, but this kind of thing does happen. To resolve this situation, begin by moving the Data Source from the RECORDING_SEQUENCE up to the SEQUENCE before it, as shown below. 

Click on the SEQUENCE layer and import the Data Source tab delimited file from earlier – This is one of the reasons why we create the Data Source file in Excel so it can be easily moved and changed!
Next, follow these steps:
  • Remove the Data Source from the RECORDING_SEQUENCE
  • Click on the Data Source
  • Highlight all the columns
  • Right click and press Delete
Now that we’ve gone and deleted our original datasource and imported it again somewhere else, we need to follow the same steps as before and tell the RESULTS_FILE to add all the necessary columns. Click on RESULTS_FILE in the Properties panel click on Columns. As before, move all the variables across left to right (you’ll also need to do this for the Eyelink DV Variablestoo). This is shown below.