Hi Inquisit Community,
I am looking for s syntax to store the reponse.latency from the (previous) n-1 trial and compare it (for example, to calculate the latency difference between the n-1 trial and the n trial) with the latency of current trial.
Is there a way to do this?
Thank you in advance;)

<values>
/ previouslatency = -1
/ currentlatency = -1
</values>

<trial sound>
/ ontrialbegin = [
values.previouslatency = trial.sound.latency;
]
/ ontrialend = [
values.currentlatency = trial.sound.latency;
]
/ ontrialbegin = [trial.sound.resetstimulusframes()]
/ stimulustimes = [0=screen, tone; 50=circleshape;2000=tone]
/ inputdevice = mouse
/ validresponse = (circleshape)
/ beginresponsetime = 50
/ responseinterrupt = frames
/ branch = [trial.release]
</trial>

<data>
/ columns = (date time subject group blocknum blockcode trialnum trialcode response correct latency values.currentlatency values.previouslatency)
</data>

thank you for your advice.
may I add one more question down here?
is there a syntax to calculate the mean (average) of response.latency every , say, 30 trials?
thank you;)

That's just simple math and conditional logic; you can do this in any number of ways.

<block example>
/ trials = [1-90 = exampletrial]
</block>

<values>
/ trialcounter = 0
</values>

<list latencies_1st_30>
</list>

<list latencies_2nd_30>
</list>

<list latencies_3rd_30>
</list>

<trial exampletrial>
/ pretrialpause = 500
/ ontrialbegin = [
values.trialcounter += 1;
]
/ stimulusframes = [1=exampletext]
/ validresponse = (57)
/ ontrialend = [
if (values.trialcounter <= 30) {
list.latencies_1st_30.appenditem(trial.exampletrial.latency);
} else if (values.trialcounter > 30 && values.trialcounter <= 60) {
list.latencies_2nd_30.appenditem(trial.exampletrial.latency);
} else if (values.trialcounter > 60 && values.trialcounter <= 90) {
list.latencies_3rd_30.appenditem(trial.exampletrial.latency);
};
]
</trial>

<text exampletext>
/ items = ("Press SPACE as quickly as possible")
</text>

<summarydata>
/ columns = (script.startdate script.starttime script.subjectid script.groupid list.latencies_1st_30.mean list.latencies_2nd_30.mean list.latencies_3rd_30.mean)
/ separatefiles = true
</summarydata>

Hi, Dave thank you for the syntax, that's quite helpful;)

I wish to use the calculated list.latencies_1st_30.mean for further calculation in the trial. Like:
/ ontrialbegin = [if (values.trialcounter > 30 && values.trialcounter <= 60){values.mean_x=1px*list.latencies_1st_30_mean}]
But the data value turned out with blank. Is there a way to fix it?
Best

/ ontrialbegin = [if (values.trialcounter > 30 && values.trialcounter <= 60){values.mean_x=1px*list.latencies_1st_30_mean}]

is clearly wrong. There is no list called "latencies_1st_30_mean". The syntax to access a list's mean property is

list.listname.mean

where listname is the name of the given <list> element, exactly as exemplified in the code in my previous reply:

/ ontrialbegin = [if (values.trialcounter > 30 && values.trialcounter <= 60){values.mean_x=1px*list.latencies_1st_30_mean}]

is clearly wrong. There is no list called "latencies_1st_30_mean". The syntax to access a list's mean property is

list.listname.mean

where listname is the name of the given <list> element, exactly as exemplified in the code in my previous reply:

Hi, Dave
I have another question regarding the mean calculation. I calculated values.latencyplus at ontrialend and
wish to also calculate the mean of  "values.latencyplus" at the same time.
however, the first "list.latencies_1st_30.mean" returned with 0, resulting in the calculated 30th list.latencies_1st_30.mean taking 0 in.
is there a way to avoid this? Thank you for your attention:) i attached the data as well as the script below.