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Trial-wise feedback on the key pressed (keyboard response)


In my experiment, after each trial I want to give a feedback concerning the exact response button pressed by the participant (disregarding the accuracy of the response).

To do that, I created a sketchpad item containing a text [response] to call the response variable, and I have put it at the end of my trial sequence, before the logger; like indicated here:

However, this does not work. I have a welcome screen at the beginning of the experiment - a sketchpad with text, duration=keypress. The feedback after the first trial refers to the response given to the welcome screen ( The feedback after the second trial refers to the response given to the first trial etc... To put it simply, the feedback n refers to the response given on n-1 trial. Obviously, I don't want that ;)

When I deleted the welcome screen, the procedure does not start and the following error appears:

The experiment did not finish normally for the following reason:

  • The variable 'response' does not exist. Tip: Use the variable inspector (Ctrl+I) to see all variables.

I have checked the variable inspector, and the response variable is there.

I guess this issue is very simple, but I cannot overcome it ;) Could anyone give me a hint?


Below I attach the structure of my experiment:


  • Hey there, so I did not figure out the reason for my issue but I overcame it using the feedback item at the end of each trial. The key here was to unclick the reset feedback option, so that the accuracy feedback at the end of the block was reliably reported (if you don't do it, the final feedback will only refer to the last trial presented).

    Hope it helps, and I'm still curious of this n-1 issue :)


  • Hi ksk

    I have a similar issue, you could provide the file of the experiment plis.

    I have this but only works with one response, i need to this work whit two keys in both conditions.


  • Hey KSK,

    yes you have to use the feedback item, not the sketchpad to show the feedback. The reason for that lies in the prepare-run-strategy of Opensesame:

    Good that you figured it out.


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