Retrieve some proxies

Question

Hello, We perform a task at fixation where a black circle sometimes turns white, the participant has to press a button on the computer keyboard when he sees a white circle appear. As you can see from the screenshots of our Data Report, we would like to retrieve some Onset Time (proxy screen time) and the Triggering Time (proxy button presses). Do not hesitate for any additional questions or information.

Answer 1

hi,

The white circle appears exactly on the onset (start) of the parent event. Thus, you can add a proxy variable to 'Onset Time' of the event and then record a value into Data Report (e.g. with Reporter element)

Registering Triggering Time is similar- create a proxy variable for the 'Triggering Time' property of the Button element and save it into Data Report after a response if given.

For both variables, it is best to save them after the event with circle, when the variables contain new values. Note the Onset Time returns a global timestamp (ms since the start of the experiment, while Triggering Time returns a local timestamp (ms since the event onset)