Time - seconds are longer than real seconds

[clowenth]

It seems like it might actually be a bit worse than that. I'm using Windows XP. When I try it in the tutorial file alone, it shows a little under 4 seconds when I let a stopwatch go for 10 seconds. In my file that I'm trying to use it in, it seems like it's closer to 5 or 6 Vizard seconds for 10 stopwatch seconds. Even factoring my double reaction time (starting the stopwatch and then stopping the stimulus and the stopwatch simultaneously), I think something's off. Any ideas?

P.S. Sorry for taking so long to respond!

[masaki]

hi can you try this modified script and see what you get? The modifications are:

- stimulus changing color is not triggered by a random time - you trigger it by hitting the space bar. So essentially, it measures the time interval between two key presses instead of measuring your reaction time.

- there is a timer function that prints the elapsed time between stimulus change and keypress.

- i've added a second viz.Data object called dd and used that one for storing the time data from the second waitkeydown function.

I tested the code with an external stopwatch and seems accurate.

import viz
viz.go()

import vizinfo
info = vizinfo.add( 'This script uses precisely timed input recording to measure your reaction time.\nPress any key when the color changes to green.\nCan you get under .2 seconds?' )

#Add quad to screen
quad = viz.addTexQuad( viz.SCREEN , pos=(0.5,0.5,0) , scale=(4,4,4) )

#Display time on screen
timeDisplay = viz.addText( 'Time:', viz.SCREEN , pos=(0.1,0.2,0) )

import viztask

import time
starttime = time.time()

stopWatch = False


def TestReactionTime():
    global starttime, stopWatch
    #Data for getting values from wait conditions
    d = viz.Data()
#    dd = viz.Data()
    while True:
        
        #Set quad to red color
        quad.color(viz.RED)
    
        #Wait random amount of time
        yield viztask.waitKeyDown(' ')
        starttime = time.time()
        stopWatch = True
        #Set quad color to green
        quad.color(viz.GREEN)
        
        #Wait for next frame to be drawn to screen
        yield viztask.waitDraw(d)
    
        #Save display time
        displayTime = d.time
        
        #Wait for keyboard reaction
        yield viztask.waitKeyDown(None,d)
        
        #Calculate reaction time
        reactionTime = d.time - displayTime
        
        #Print and display time
        print 'Reaction time:',reactionTime
        timeDisplay.message( 'Time: %.5f' % (reactionTime) )
        stopWatch = False

viztask.schedule( TestReactionTime() ) 

def showTime():
	if stopWatch:
		print time.time() - starttime
vizact.onupdate(-100, showTime)

Best,
Masaki

[clowenth]

Ok, the time works out now when I use that code. So we know it's not a computer problem. However, the random timing is an important part of the code, since I want to use it as a side task that the user has to attend to at unexpected intervals. Any suggestion as to how to make that work? Thanks!