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Error in presenting each item once and feedback error

OS (e.g. Win10): Mac OS X
PsychoPy version (e.g. 1.84.x): 1.83.04


I created an experiment with text stimuli each containing 2 sentences. For every item participants have to decide, wether the last sentence is grammatically correct or incorrect. After their key press, they get a feedback about the answer.

I created a .xlsx-file for my stimuli and conditions with a column ‘corrAns’ for my feedback loop. I tried to make everything similar to the stroopExtended demo. I want to present every item just once, so I selected a random loopType and nReps = 1. Within the routine the text was set every repeat (everything like in the stroopExtended demo). Everything works quite well dispite the presentation of my items.

The problem:
Some random items are presented twice or three times in series although I selected nReps = 1. For the first presentation of the item the feedback works well, but then it gives only the ‘wrong’-feedback for every further item repetition. When I have a look into the data file these trials of item repetitions are filled with ‘None, None, None’. I get no error message or nothing else.
Does anybody has an idea about this?


Hello, welcome along. It is a bit hard to follow the description of your problem. Could you post a screenshot showing the flow of your experiment?

Hi Michael,


Routine1-3 is a sequential presentation of one item. In routine3 participants are asked to respond (displayed in screenshot).

That’s how my data file looks like:

The repetitions of the prior item are filled with ‘None’.

Do you need any further screenshots or information?


Yes, we probably need to see the actual settings in your loop dialog, keyboard component, and text stimuli.

But as a first suggestion, it looks like you have blank lines towards the end of your conditions file (the likely cause of the None values in your data file). Often in a spreadsheet it is hard to tell if cells are actually blank (compared to, say, containing a space character). I would recommend using a .csv file instead of .xlsx. That way, the file can be inspected in a simple text editor and you can instantly verify whether there are blank lines present.

Hi Michael,

sorry for my late reply.

It seems that additional space characters in my condition file were the problem. Thanks for your recommendation of using a csv-file instead of xlsx. That reveald these invisible characters I was never thinking of.
Sorry for this simple problem. :flushed: My fault.


Not at all, helping solve problems is what this forum is for. Plus it provides a record that can help someone else in the future.