Timing across multiple stimuli

I’m setting up what is basically a continuous detection task. There is a continuous series of stimuli presented of which one is designated the target and the subject has to press the button whenever the target is presented. Stimuli are presented at a fast rate (4/sec roughly) so most of the time the target has already been replaced by another stimulus when the subject responds.
I know I can set the response timer to re-start at the beginning of each target. At present we are using a trial structure (so 10 stimuli per trial and the target is in varying positions in the trial) but what I want to check is if the timer is reset at the beginning of each trial as well? This seems to be the case from looking at the output.
Subjects sometimes respond when they shouldn’t and I need to record those but I need to be able to work out when the RT on those errors is from (and hopefully an easy way or sorting them out when we do the averaging across trials).

Assuming that you are using version 4, there is an option to save an additional “Cumulative time” column in the data where the timer is reset only once at the beginning of the experiment.

To add this column, click on the Experiment menu and select Options. A dialog appears. In the list on the left hand side, click on Columns to Save. You will then see a checkbox labeled Cumulative time. Make sure it’s checked (it’s turned off by default).