Hi,
I have this issue. I need to vary presentation time within a trial based on the accuracy of participant's responses. The thing is that I need to find a perceptual threshold for each individual participant. So within this trial:
<trial thresh_setup>
/ stimulustimes = [1 = fixation; 1001 = mask1; 1302 = noreplace(CS_neg, non_words); 1903 = mask2; 2204 = rect, Q_word, P_nonword]
/ validresponse = ("q", "p")
/ correctresponse = ("q")
</trial>
I am starting with 600 ms presentation of 'CS_neg' or 'non_words'. If a participant correctly answers, I need to reduce the presentation time by 50ms. And this reduction by 50ms should follow until participants cannot give a correct answer at the specific presentation duration, which would approximate their individual perceptual thresholds.
Can you give me any hints how to do that?
All the best,
Robert