[solved] How do I collect the keyboard_response after a stimulus disappears?

jsjun

Hi, Sebastiaan. I'm jongsup, your Korean colleague who is teaching Psycholinguistics using OpenSesame at a Korean university. Hope you remember the e-mail correspondence we had last winter.

Here's my question. I want to present a target stimulus for 500ms. That is, the target stimulus should disappear in 500ms. But I want to set the timeout for keyboard_response to 2000ms. That is, the response should be recorded for 2000ms (even after the target stimulus goes away).

How can I achieve this? Can you suggest me any useful inline script for this? It seems that I need something more than the 'self.sleep()' script.

Thanks in advance for your help and efforts.

From JS

sebastiaan

Hi Jongsup,

Yes, of course I remember! Great to heard that you're actually using it now.

Below is a quite elaborate inline script that should do what you need. Basically, it collects a response first with a timeout of 500ms. If no response is collected during that time, the display is blanked and a response is collected again for 1500ms, giving a total timeout of 2000ms. It also maintains feedback variables, etc., which is actually most of the script. Importantly, the script assumes that it is preceded my a sketchpad called my_sketchpad with a 0ms duration. So you can just present the target stimulus on a regular sketchpad.

Hope this helps!

Cheers,
Sebastiaan

# This code snippet assumes that it is
# preceded my a sketchpad called 'my_sketchpad'
# with a 0 duration.
#
# The code below collects a response for a
# maximum of 2000ms. After 500ms the canvas
# is blanked.

from openexp.canvas import canvas
from openexp.keyboard import keyboard

# Uncomment for 0.25 or earlier
# exp = self.experiment

# Some settings
timeout1 = 500
timeout2 = 2000
allowed_keys = ['z', 'm']

# Create keyboard and canvas objects
my_keyboard = keyboard(exp, keylist=allowed_keys)
my_blank_canvas = canvas(exp)

# Set actual timeout. By taking into account
# the current time and the timestamp of
# my_sketchpad we reduce temporal jitter
timeout = timeout1  - self.time() + exp.get('time_my_sketchpad')

# Collect a keyboard response with a stim_dur timeout
# and show a blank canvas afterwards
resp, time = my_keyboard.get_key(timeout=timeout)
my_blank_canvas.show()

# If no response has been given, we wait for another
# post_stim_dur milliseconds
if resp == None:
    timeout = timeout2 - self.time() + exp.get('time_my_sketchpad')
    resp, time = my_keyboard.get_key(timeout=timeout)

# Set response, correct, and response time
response_time = time - self.get('time_my_sketchpad')
response = my_keyboard.to_chr(resp)
if not self.has('correct_response'):
    correct = 'undefined'
elif response == self.get('correct_response'):
    correct = 1
else:
    correct = 0
exp.set('response_time', response_time)
exp.set('response', response)
exp.set('correct', correct)

# Maintain feedback variables. This ensures that
# you can use the feedback item as usual
exp.total_responses += 1
if correct:
    exp.total_correct += 1
exp.total_response_time += response_time
exp.acc = 100. * exp.total_correct / exp.total_responses
exp.avg_rt = exp.total_response_time / exp.total_responses
exp.accuracy = exp.acc
exp.average_response_time = exp.avg_rt

jsjun

Goodness! How can I express my deepest gratitude to you, Sebastiaan? I will definitely test this inline script with my students, and may ask you further questions. At the moment, I want to let you know that I have taught more than 80 students how to use OpenSesame this semester here in Korea. We all admire your help and achievement!

JS