Conditional Statements and Variable: True/Correct Response

Next, we need to tell Experiment Builder when the answer is correct or incorrect. Notice in our datasource we already have a column called “expected_button” which lets us know which button press is correct for each trial. We can use this information to create what is called a “Conditional Statement”. Conditionals are common in programming, but they follow the logic of:

  • IF response is correct do something
  • IF response is incorrect do something else

In our case, the conditional will appear after the KEYBOARD response but before UPDATE_ATTRIBUTE. We want to play the error sound only when the response is incorrect.

Conditionals and Feedback

To do this, let’s begin by creating a new variable to record accuracy. We do this in the same way we created RT and BUTTON_PRESS earlier:

  • Create a new variable called RESPONSE_ACCURACY
  • Set the default value as any number that you won’t use i.e. we will use 0 and 1 for correct and incorrect, so I set the default as 999

This process is shown below.

We now need to insert some new actions and triggers. Follow these steps:

  • Delete the link between KEYBOARD and UPDATE_ATTRIBUTE
  • Drag a CONDITIONAL Trigger from the Trigger bar
  • Notice it is shaped like a triangle and the button two points have a cross and a tick
  • We will give the triangle a conditional statement : this is sketched out below.



To implement this, first insert a CONDITIONAL Trigger from the Trigger bar. Then Join the KEYBOARD response to the top of the triangle as shown below.
Click on the new CONDITIONAL and look at the Properties panel. Instead of what is in there at the moment, we want to say: if the keyboard press is correct, as stated by the column “expected_button” in the Data Source then the conditions have been met. Or to put it another way,




Data Source.expected_button THEN [DO SOME ACTIONS]. The start of this is shown below.

So IF the condition is met and the KEYBOARD response is the same as the expected_button in the datasource then we follow the corner of the CONDITIONAL Trigger with the tick on it. Here’s a diagram showing this:
2014-04-06 17_04_34-Developing Experiments using Experiment Builder - Microsoft PowerPoint

Next, we need to set up the RESPONSE_ACCURACY in UPDATE_ATTRIBUTE. Here are the steps to follow, with an animation below:

  • Click on UPDATE_ATTRIBUTE and in the Properties panel click on Attribute-Value List
  • Set the Attribute as the RESPONSE_ACCURACY variable. Remember the Attribute is what you want to change
  • Set the Value to 1. Remember the Value is what you want the Attribute to be changed to. Typically, a value of 0 is used for incorrect and 1 is used for correct, but you can use whatever values you like.
Next, join the side of the CONDITIONAL with the tick to the UPDATE_ATTRIBUTE, as shown below, and then that side is complete!
2014-04-06 17_09_06-Developing Experiments using Experiment Builder - Microsoft PowerPoint