Two correct responses for one stimulus

szanszika

Hi,

I'm preparing a reaction time experiment for Android that contains the followings: a number appears (1, 2, 3 or 4) and the participant has to touch the right number below. The allowed responses (1-4) are present during the full block. I would like to make this experiment run in three different conditions. The participant has to use 1. his right hand; 2. his left hand; 3. his both hands. Since I would like the experiment run on Android, the screen area is divided into 8 columns. From left the first four columns (1-4) contain the allowed responses for the left-hand condition. The second four columns (5-8) contain the allowed responses for the right-hand condition. In the both-hand condition all the eight columns are active in wich the order of the allowed responses is 4-3-2-1-1-2-3-4.

I'm stuck with the problem if I can set two responses as correct in the both-hand condition. For example in the both-hand condition for the stimulus '4' the correct response with left hand is in the column n. 1 (allowed response '4') and the correct response with right hand is in the column n. 8 (allowed response '4' also).

In the construction of the experiment after the sketchpad of the target number I may set two touch responses to register both hands' responses. But is there any solution to set two items as correct response simultaneously? Any advice could help!

Cheers,
Alexandra

sebastiaan

Hi Alexandra,

The keyboard_response item only accepts a single correct response. But you can easily implement more complicated logic using an inline_script. For example, the script below checks whether a response is part of a list of correct responses, and records the response accordingly.

Do you see the logic of the script? You'll probably need to change it a bit, but basically I think it does what you need.

This code should be in the run phase of an inline_script, and should replace a keyboard_response.

# Define your correct responses
correct_responses = '1', '2'
# Collect a response
t0 = clock.time()
my_keyboard = keyboard(keylist=['1', '2', '3', '4'], timeout=5000)
response, t1 = my_keyboard.get_key()
# Add the response to the response history
responses.add(
    response=response,
    response_time=t1-0,
    correct=1 if response in correct_responses else 0
    )
# Print the response history to the debug window
print(responses)

See also:

• http://osdoc.cogsci.nl/3.1/manual/python/keyboard/
• http://osdoc.cogsci.nl/3.1/manual/python/responses/

Cheers!
Sebastiaan