+xHi, I'm making an auditory task. I want to present 72 trials, half (36) control conditions and half (36) experimental conditions. I have 4 control conditions and 3 experimental conditions. In <sounds> I have have repeated each of the four control conditions 9 times so that there are 36 stimuli in total and I have repeated each of the experimental conditions 12 times so that there are 36 stimuli in total. I have the select mode as noreplace. In blocks I have put /trials = [172 = noreplace(control, experimental). I do get 36 control trials and 36 experimental trials but the stimuli aren't always presented the correct number of times. Sometimes the control conditions are presented for example 8, 10, 9 times rather than 9, 9, 9 times. Is there a way to overcome this? Thanks, Anna If you run a practice block with trials that sample from the respective sound elements before the test block that has /trials = [172 = noreplace(control, experimental)] (resulting in 36 control trials and 36 experimental trials) make sure to reset the selection pools of the various <sound> elements' selection pools at the start of the <block> (/onblockbegin). Here's an example using <text> elements (works the same with <sound>: <block test> / onblockbegin = [reset(text.control_stim); reset(text.experimental_stim);] / trials = [172 = noreplace(control, experimental)] </block> <trial control> / stimulusframes = [1=control_stim] / validresponse = (57) / trialduration = 10 </trial> <trial experimental> / stimulusframes = [1=experimental_stim] / validresponse = (57) / trialduration = 10 </trial> <text control_stim> / items = control_items </text> <text experimental_stim> / items = experimental_items </text> <item control_items> / 1 = "C1" / 2 = "C1" / 3 = "C1" / 4 = "C1" / 5 = "C1" / 6 = "C1" / 7 = "C1" / 8 = "C1" / 9 = "C1" / 10 = "C2" / 11 = "C2" / 12 = "C2" / 13 = "C2" / 14 = "C2" / 15 = "C2" / 16 = "C2" / 17 = "C2" / 18 = "C2" / 19 = "C3" / 20 = "C3" / 21 = "C3" / 22 = "C3" / 23 = "C3" / 24 = "C3" / 25 = "C3" / 26 = "C3" / 27 = "C3" / 28 = "C4" / 29 = "C4" / 30 = "C4" / 31 = "C4" / 32 = "C4" / 33 = "C4" / 34 = "C4" / 35 = "C4" / 36 = "C4" </item> <item experimental_items> / 1 = "E1" / 2 = "E1" / 3 = "E1" / 4 = "E1" / 5 = "E1" / 6 = "E1" / 7 = "E1" / 8 = "E1" / 9 = "E1" / 10 = "E1" / 11 = "E1" / 12 = "E1" / 13 = "E2" / 14 = "E2" / 15 = "E2" / 16 = "E2" / 17 = "E2" / 18 = "E2" / 19 = "E2" / 20 = "E2" / 21 = "E2" / 22 = "E2" / 23 = "E2" / 24 = "E2" / 25 = "E3" / 26 = "E3" / 27 = "E3" / 28 = "E3" / 29 = "E3" / 30 = "E3" / 31 = "E3" / 32 = "E3" / 33 = "E3" / 34 = "E3" / 35 = "E3" / 36 = "E3" </item> If you run this, you should end up with exactly 9 x C1, 9 x C2, 9 x C3, 9 x C4 and 12 x E1, 12 x E2, 12 x E3
