GNAT task: All responses recorded as -1 (case 10626)

Hello,
I used the csv files in the v2006 samples folder as a template for creating a simple go/no go task. It runs smoothly, but now that I look at the data, it has recorded all responses as -1 (NULL) and the response times as 146, despite the fact that during execution of the the attached test data file, I pressed spacebar on every lowercase letter (TRUE) and on some upper case letters (FALSE).

Is there something that needs to be corrected in the input file (also attached) to correctly record the responses?

Thank you--I appreciate any feedback you can provide!

-Scout

The values of 146 occur because each letter stimulus is displayed for 150ms. Using 0-150! in the MinMax field of the style file in combination with a -1 keypress in the trial means that the next trial will begin 150ms after the letter at the end of each trial is first put on the screen. Because 150ms is most likely too short a time for participants to see the letter and attempt to press the space key, the data file records a uniform response time of 146 to show how long the letter was on the screen. You can check the log file to see how each stimulus of a trial was onscreen and the load time for the trial.

If you wanted the letter stimulus displayed for a certain amount of time but still wanted to give participants enough time to respond, you need to define the response window in the MinMax field. If you wanted to give participants 500ms in which to respond, you would use 0-500! in the MinMax field. If you wanted to still only display each letter at the end of a trial for 150ms, then you could use full150 in combination with whatever keypresses you define the stim field. Take a look at the attached input file for an example.

Hope this helps!

Thank you so much for your quick and helpful response! That fixed the problem; RTs and keystrokes are recording correctly now.

Glad to hear that it worked! Please don't hesitate to send any other questions that you may have in the future. Good luck with your study!