The rwdeccondition attribute specifies a list of performance conditions that cause the response window to be decremented on the next block.
<response>
percentcorrect | A positive integer expressing the percent correct. |
latency | An positive or negative integer expressing the latency threshold in milliseconds relative to the window center. |
This attribute defines pairs of latency and accuracy thresholds. If any of these performance thresholds are met, the onset of response window is adjusted to occur earlier during the next block. Performance is evaluated against the thresholds at the end of the block. The threshold is met if the subject’s percent correct is greater than or equal to the specified percent correct and their mean latency is less than or equal to the sum of the specified latency and the window center. If multiple conditions are specified, the response window is decremented if any single condition is true. See Adjusting the Response Window for details.
The following response defines a response window with an initial center of 500 ms and width of 150 ms. A black exclamation point appears on the screen during the window. If the response is in the window, it turns green and remains on the screen for 300 ms. Otherwise it turns red. The window is incremented by 75 ms if the mean latency for the block is greater than the current center + 50 ms and the percent correct is less than 60%. The window is decremented if the mean latency for the block is 50 ms earlier than the window center and the percent correct is greater than or equal to 80%. The maximum window center 1000 ms and the minimum is 200 ms:
<response windowprocedure>
/ mode = window
/ rwcenter = 500
/ rwwidth = 150
/ rwinccondition = [(60, 50)]
/ rwdeccondition = [(80, -50)]
/ rwincunit = 75
/ rwdecunit = 75
/ rwmincenter = 200
/ rwmaxcenter = 1000
/ rwlatencymetric = mean
/ rwstimulus = blackexclamationpoint
/ rwhitstimulus = greenexclamationpoint
/ rwmissstimulus = redexclamationpoint
/ rwhitduration = 300
</response>