[solved] How to ignore incorrect mouse responses?

Darby

Hi,

I have a very simple program where you touch a red dot that appears randomly on the screen. If you click the dot that is a correct response. However, if you click somewhere not on the dot, I want nothing to happen. Currently, when you make an incorrect response the program advances to the next trial. I basically want participants to stay on a trial until they click the dot.

Here is my mouse inline script, where I think I should be controlling this. I'm guessing something is wrong with my loop.

from openexp.mouse import mouse
from math import sqrt
my_mouse = mouse(exp, visible = False)

# Use Pythagoras to determine the click error 

xc = self.get('width') / 2
yc = self.get('height') / 2
# Determine x and y error
dx = self.get('cursor_x')- xc - self.get('xRed')
dy = self.get('cursor_y')- yc - self.get('yRed')

target_positions = [(dx, dy)]

# The maximum error from the target center
maxClickErr = 100
clickErr = sqrt(dx**2 + dy**2)

hit = False

for target_x, target_y in target_positions:
    if clickErr <= maxClickErr:
        exp.set('correct', 1)
        hit = True
    if not hit:
        pass

sebastiaan

Hi,

Your script is a bit funky in a number of ways. First off, you define a mouse object, but never use it, apparently because you use a mouse_response item to collect mouse clicks. Second, you define target_positions list, which is walked through, but is functionally ignored. (And at any rate does not contain a list of target positions, as you would expect!)

Below you see a modified version of your script, which should do more-or-less what you want. The idea is to use a mouse object to collect clicks in an endless loop that is broken only when a click is close enough to the target (defined by the xRed and yRed experimental variables). Does that make sense? This script is instead of a mouse_response item, so you can remove that from your trial sequence.

It might also be a good idea to walk through a basic Python tutorial, to get a grip on using while-loops, etc.

• http://osdoc.cogsci.nl/python/about/#learning-python

Cheers!
Sebastiaan

from openexp.mouse import mouse
from math import sqrt

# Create a mouse object
my_mouse = mouse(exp, visible=False)

# The maximum error from the target center
maxClickErr = 100

# Get the coordinates of the display center, which are necessary to convert
# from top-left to center-based coordinates.
xc = self.get('width') / 2
yc = self.get('height') / 2

# Loop until we get a hit (i.e. a correct mouse click)
while True:
    button, pos, timestamp = my_mouse.get_click()
    cursor_x, cursor_y = pos
    # Determine x and y error
    dx = cursor_x - xc - self.get('xRed')
    dy = cursor_y - yc - self.get('yRed')
    # Break the loop if there is a hit (use Pythagoras for click error)
    clickErr = sqrt(dx**2 + dy**2)
    if clickErr <= maxClickErr:
        break

Darby

Thanks Sebastiaan! This works perfectly. I will definitely have a look at the python training.