Quick Picture Reaction Problem

Ozgun

Hi,
My experiment includes picture shows. But I need to show the pictures in a very short time like 250 ms. And I will take reaction during the picture show. My experiment structure is basically "fixation-picture-response tool-logger tool". Picture duration is 0 and response duration is 245 ms. Also I set the correct response variables and allowed response variables. However, correct datas are always "0" and response_experiment datas are always "none". I can't understand why the problem is the participants or the program or my computer.

All the best,
Özgün

sebastiaan

Hi Özgün,

If you set the response timeout (which I assume is what you mean with response duration) to 245 ms, then any responses slower than 245 will be a timeout (i.e. 'None'). And because participants rarely respond within 245 ms, you mostly get timeouts.

For this kind of structure, you can use the coroutines item. This allows you to specify when in time sketchpads should be presented, in your case a target at 0 ms and a blank at 245 ms. And then you can specify that a keyboard_response should be running throughout the entire duration of the coroutines, for example from 0 to 2000 ms.

• http://osdoc.cogsci.nl/3.2/manual/structure/coroutines/

Cheers!
Sebastiaan