[open] Regarding Reaction Times

booradley

Howdy,

By looking at the output I'm guessing that the RTs are calculated from the response screen presentation until the participant responds.

However, I was wondering if instead of the already calculated RT is it possible to record or calculate the machine stamp time of when the participant responds?

I ask this because I would like to be able to minus a previous sketchpad response time from this.

In other words I'm not exactly looking to see the RT from the response screen but rather I want to see how long it took a participant to respond from an earlier screen. This is all in ms' so there is no issue of responding before being able to record.

Thanks,

Boo.

lvanderlinden

Hi Boo,

I was wondering if instead of the already calculated RT is it possible to record or calculate the machine stamp time of when the participant responds?

The machine timestamp of the response can be calculated by adding the 'respones_time' variable and the 'time_sketchpad' variable (which is the timestamp of the item call, in ms). Of course, the exact name of the latter depends on how you defined your sketchpad: If it's called 'show_stim', the variable containing its timestamp will be called 'time_show_stim'.

I want to see how long it took a participant to respond from an earlier screen.

To this purpose, you could also decide to let the variable 'response_time' correspond to exactly this interval by making the following change to the OpenSesame script (not to be confused with inline code) of the relevant sketchpad item. Iin order to do so, click the terminal icon at the top right of the sketchpad tab and change:

set start_response_interval "no"

to

set start_response_interval "yes"

Note that by doing so, responses will still only be corrected after the keyboad_response item is called; this procedure only changes the 'response_time' variable.

So, you can either change the 'response_time' variable beforehand or calculate the appropriate variable retrospectively, whatever you find more convenient.

Does this help?

Best,

Lotje

booradley

That's great.

I'll have a look when I get back from a weekend wedding.

Thanks,

Boo.

lvanderlinden

Hi Boo,

You're welcome! Have a nice weekend!

Lotje