Problem with Correct output column and actual correct (case 5897)

[I][edited by moderator][/I]

I have been running a few experiments in which I use two "stim" columns in the same line, both requiring response. In the log output file the "correct" column corresponds to the actual "correctness" about 80% of the times, but the other 20% do not correspond. For example, if I program the response to be rt:32,37 then if the participants pressed 32 it will say "true" for ~ 80% of the trials but for some reason it will say "false" for ~20% of the trials. I've gone back to look at several other experiments and this is the case in all of them. It doesn't happen if there's only one "stim" column per line. That means that when there is more than one "stim" column than requires [a] response [that] the "correct" column [may not] provide the [correct] data. [...]

Hi tfk. This sounds like a frustrating problem, especially when the data do not appear to record as expected. Let me ask a couple of questions to get started and I’ll do my best to help you sort this out.


[LIST=1][*][FONT=Calibri] [/FONT]You said that the “correct” column in the log file does not accurately record the correct response. Does the actual key pressed record correctly in the short data file (e.g. the other spreadsheet file in the data folder with the log folder)? [*][FONT=Calibri][/FONT]You said this error happened in several other experiments. Did these experiments all run on the same machines with the same versions of DirectRT? Did you try to run the troublesome input files on different machines and/or with different versions of DirectRT? I'm curious if it happens no matter what version of DirectRT or machine you use to see if we can limit it to the input file itself.[*][FONT=Calibri][/FONT]What version of DirectRT are you using to run your experiment?[*][FONT=Calibri][/FONT]If it occurs for about 20% of the time, is it at the same point in the experiment every time or does it change with different subjects and experiments? It would be helpful if you would upload a version of the file to this thread that causes this error so that I can see if I can replicate the problem on my version of DirectRT 2012.[/LIST]

I hope that this will help us solve your dilemma.


Sincerely,
Psychboiler.

Hi,

I'm having a similar problem. I have more than one stimulus in the same row and the output is not showing any results, not the key press nore the correct response. No matter what the kry press, the answer is TRUE.

WE are running direct rt 2006 in out lab.

I'm enclosing an example.

thank you!

Hi tamar,

I think that the problem may lie in the cells you have in the time column (column R of the input file as it appears when I open it in Excel) that contain

2000rt:203,205,full

I do not think that you can have a number in front of any key presses that you define with the rt: command in a time column in an input file. I would suggest removing the 2000 from those cells and seeing if key presses on those trials are recorded in the output files.

Cheers.

Psychboiler

thank you. I think that would work.

If I want the stimulus to appear for 2000 ms, in full even after key is pressed, how would I configure that in the input file?

Your questions are distinct from the initial post, and are different issues.
You ask two separate things in your post. The first is a Direct RT syntax issue, what I will address to build on Psychboiler's reply. The second is also a syntax issue, but a different one, which I will address separately.

In order to test the file that you had uploaded, I needed to make a few adjustments (I don't have a style 9 or 10 specified). In your file I set all style requests to "1", and edited your Column R, "time" column to invoke correct syntax, such that: "rt:203,205,full"

After testing it, in the "1.CSV" file, the values under "Correct" reflect a my hits and misses, both True and False appear, rather than all True, as you had seen before. The open-ended text also saves.

thank you for your response.

How would I keep the 2000 ms for that stimulus eventhough a key was pressed?

Hi Tamar,

You will need to do two things to display the stimulus for 2000 ms even if a key is pressed:

1) Put the word full at the end of any keypresses you define in cells of the time column for your trials where you want the stimulus to appear for 2000ms (See timdrichie's reply for an example)

2) In the style file you will use for this input file write the value of xxx-2000 (where xxx is the minimum amount of time in ms you want the stimulus to appear on screen) in the MinMax column of whatever styles you are using with that input file.

You can find instructions how to do this in the interactive instructions by going to Style Editor > MinMax - Setting RT Limits.

Cheers.

Psychboiler

Yes, there do seem to be different issues going on here! TFK--If I recall correctly, there is only one correct column created for any given trial. Its primary purpose is as a convenience for single response trials so that the user does not need to compute a "correct" variable during analysis. In cases though where multiple responses are collected, I believe the "correct" column is not as useful. It should correspond to the final response, I believe. If so, you should be able to see if there is actually 100% correspondence between TRUE/FALSE and whether the particpant pressed the correct key for their [I]second[/I] response. If not, please feel free to attach your input and log data files and I'll take a look!

And Tamar--I think Tim and PsychBoiler have you covered?