Hi there -
I am trying to use DotStim, but I think I’ve discovered a bug.
I’m trying to create a condition with noise dots only (coherence =0) and where noiseDots = ‘direction’ (each noise dot takes a random but constant direction).
I’ve tried playing with a number of parameters, but as far as I can tell, the direction is updating every frame, which means that noiseDots=‘direction’ is actually producing the same output as noiseDots=‘walk’
Could someone take a look to see if this is the case?
Here is my initial instantiation:
imgDots = visual.DotStim(
win, units=‘deg’,fieldShape=‘circle’,
nDots=nDots,dotSize=dotSize,dotLife=dotLife,speed=dotVel[0],
signalDots=‘different’,noiseDots=‘direction’,
fieldPos=(0,0),fieldSize=patchRad*2
)
… and then in my display loop, I update
imgDots.coherence = dotCoh[thisBlock]
imgDots.speed = dotVel[thisBlock]
imgDots.draw()
For the block in question,
dotCoh = 0
dotVel = 0.05
For my actual experiment, I will use a dotLife of 3 to 6 frames (50 - 100ms), but for testing I’ve been trying out much longer lifetimes so I can track the dots (e.g. 60 frames = 1000ms).
Thanks,
Ed