how to implement no/go task in opensesame?

rampriya darshini

I'm a novice to opensesame and im trying to build Hester(2005) error awareness task in openseseme for my master thesis. Below is a brief description of the task.
" error-awareness task presents a serial stream of single color words in congruent fonts, with the word presented for 400 ms followed by a 1600 ms inter-stimulus interval. Participants were trained to respond to each of the words with a single 'Go trial' button press, and withhold this response when either of two different circumstances arose. The first was if the same word was presented on two consecutive trials (Repeat No-go), and the second was if the word and font of the word did not match (Stroop No-go). To indicate 'error awareness' participants are trained to press a second key."
I have completed the stroop part but i have no idea how to set the no-go conditions .Please help me out.

sebastiaan

Hi,

So you basically need a variable that indicates whether the previous word was the same as the current word. Is that right? You could accomplish that by inserting the following in the Prepare phase of an inline_script at the start of the trial:

if 'previous_word' in var and var.previous_word == var.word:
    var.word_repeated = 'yes'
else:
    var.word_repeated = 'no'
var.previous_word = var.word

You can probably tell what the script does, namelijk check if previous_word matched word (so it assumes that you're using the variable word for your words) and, if so, set word_repeated to 'yes'. You can then use the variable word_repeated to determine whether this is a go or a no-go trial. Does that make sense?

You may also want to remove the previous_word variable at the beginning of each block, so that you don't get carry-over effects from block to block, with a script like this:

del var.previous_word

Cheers!
Sebastiaan

rampriya darshini

Thanks . I have two more doubts.
1.
it shows the following error when i run it.
phase: prepare
item: inline_script
line: 1
exception message: name 'var' is not defined
exception type: NameError
2. i also would like to know how can i pseudo randomize my trials.say,minimum of three go trials between two go trials.

sebastiaan

Regarding the error: It seems that you're using an old version of OpenSesame (<= 2.9), in which the var object didn't exist yet. Is that right? If so, I would recommend upgrading to 3.1--it's much smoother!

i also would like to know how can i pseudo randomize my trials.say,minimum of three go trials between two go trials.

See the pseudorandomization option of the loop item:

• http://osdoc.cogsci.nl/3.1/manual/structure/loop/#pseudorandomization

Cheers!
Sebastiaan