Two versions of the Stroop test are available in PEBL. The Stroop test is a classic test of attentional filtering. It is typically demonstrated as a reading versus color naming task, where reading is more automatic and thus less impacted.
Located in battery/stroop/stroop.pbl and battery/stroop/vstroop.pbl
The standard PEBL stroop test compares color naming versus word naming under three response conditions (impacting what the screen looks like). These are specified in colorresp in the output data, and are:
0: black color names 1: in-color color names 3: color patches (no text)
Results typically produce interference opposite to what naming does, because it is easy to match the color shade between the stimulus and response, but hard to actually read the color, which is now interfered with.
##The number of trials per block (and condition) blocklength <- 50
 Data Output
For the standard stroop test, data are output in a file stroop-<gsubnum>.txt, with the following columns:
sub is the subject code entered at startup block is the block number (different response types) trial is the trial number type is block type (1= response by name, 2= response by shade) colorresp is whether the response targets are labeled in color: 0 is black text, 1 is in-color text 3 is just shade (no text) cond is the stimulus condition 1-4: 1. color name and color match. 2. color name does not match color. 3. color name normal; color is black 4. color name is 'xxxxx'; color is normal cond2 is a 3-level translation of cond. No block contains both conditions 3 and 4, so these are mapped into the same single-feature condition called 3. (1->1, 2->2, 3->3, 4->3) shade is the name of the stimulus's color wordname is the stimulus word resp is the actual response (1-4) made corr is whether it is correct respnum is a counter regarding how many times they responded to the stimulus (they may have taken multiple errors before getting it right). startTIME is the absolute time (in ms) of the start of trial rt is the time (in ms) of the response Note that every trial must be finished "correctly", which means if you make an error, the data line Can get logged every time until you get it right.
Basic response times and accuracies are also given for each condition in the file stroop-summary-X.txt.
Troyer, A. K., Leach, L., & Strauss, E. (2006). Aging and Response Inhibition: Normative Data for the Victoria Stroop Test. Aging, Neuropsychology & Cognition, 13(1), 20–35. doi:10.1080/138255890968187