HELP PLEASE!!! Need to know how to measure response time

Comments

• brusil

  October 2017

  Hi, Maddie,

  When you add a keyboard_response item, it automatically records the response time in the response_time_keyboard_response variable (the name of the variable depends on the name of the item like response_time_{item_name}). A response_time variable is also created if I'm not mistaken (I don't know if this depends on something else, like providing a correct_response).

  Do not mistake the previous for time_keyboard_response as this refers to the time, from the start of the experiment, at which the keyboard_response took place. (I think that all predefined variables with the naming time_{item_name} refer to the experimental time at which the item took place).

  If you add a logger item, with either the option log all variables (recommended) or directly asking for the intended vars, the desired response times should appear in the log file.
  Note that if you have a trial-based experiment you probably want to log on a trial basis. If you add the log item outside the trial_sequence you may be logging just the last trial information as the values of these vars are overwritten.

  You'll find other predefined vars that relate to the response time or the correctness of the response, such as: average_response_time or avg_rt, total_response_time, accuracy or acc, response_keyboard_response, correct_keyboard_response, total_responses, total_correct, etc.

  I hope this helps!
  Cheers,
  Bruno
• maddiehadley123

  October 2017

  I have a 30 minute video and within that video there are 21 events. I want to measure how quickly participants respond to the different events. When I add a keyboard response item it only records one response for the whole video. How can I record response times for more than one event in the video? Do I need to add 21 keyboard responses and 21 loggers?
• brusil

  October 2017

  I'm not familiar with the use of video media in OpenSesame or with your experimental design. If you have 21 different keyboard_response elements, they will have different names and will be stored in different variables, so you can use the logger item just once, after them, to log them all.
  I don't know if there is any way to avoid adding the the 21 individual keyboard_response items. Perhaps @sebastiaan can help you.
• sebastiaan

  October 2017

  Assuming that you're using the media_player_mpy plugin, you could do this by first setting the duration to 'sound' and then using a simple script that writes a message to the log file every time that a key is pressed. Also, in this example script, the 'space' key stops playback, but you can easily change that.

  

  Does that make sense? Note: If you do this and use a logger, you will get a very messy logfile.

  
  
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