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"""measure your JND in orientation using a staircase method"""
from psychopy import core, visual, gui, data, misc, event
import time, numpy, random
try:#try to get a previous parameters file
expInfo = misc.fromFile('lastParams.pickle')
except:#if not there then use a default set
expInfo = {'observer':'jwp', 'refOrientation':0}
expInfo['dateStr']= data.getDateStr() #add the current time
#present a dialogue to change params
dlg = gui.DlgFromDict(expInfo, title='simple JND Exp', fixed=['dateStr'])
if dlg.OK:
misc.toFile('lastParams.pickle', expInfo)#save params to file for next time
else:
core.quit()#the user hit cancel so exit
#make a text file to save data
fileName = expInfo['observer'] + expInfo['dateStr']
dataFile = open(fileName+'.csv', 'w')#a simple text file with 'comma-separated-values'
dataFile.write('targetSide,oriIncrement,correct\n')
#create the staircase handler
staircase = data.StairHandler(startVal = 20.0,
stepType = 'db', stepSizes=[8,4,4,2,2,1,1],
nUp=1, nDown=3, #will home in on the 80% threshold
nTrials=1)
#create window and stimuli
win = visual.Window([800,600],allowGUI=True, monitor='testMonitor', units='deg')
foil = visual.PatchStim(win, sf=1, size=4, mask='gauss', ori=expInfo['refOrientation'])
target = visual.PatchStim(win, sf=1, size=4, mask='gauss', ori=expInfo['refOrientation'])
fixation = visual.PatchStim(win, color=-1, colorSpace='rgb', tex=None, mask='circle',size=0.2)
#and some handy clocks to keep track of time
globalClock = core.Clock()
trialClock = core.Clock()
#display instructions and wait
message1 = visual.TextStim(win, pos=[0,+3],text='Hit a key when ready.')
message2 = visual.TextStim(win, pos=[0,-3],
text="Then press left or right to identify the %.1f deg probe." %expInfo['refOrientation'])
message1.draw()
message2.draw()
fixation.draw()
win.flip()#to show our newly drawn 'stimuli'
#pause until there's a keypress
event.waitKeys()
for thisIncrement in staircase: #will step through the staircase
#set location of stimuli
targetSide= random.choice([-1,1]) #will be either +1(right) or -1(left)
foil.setPos([-5*targetSide, 0])
target.setPos([5*targetSide, 0]) #in other location
#set orientation of probe
foil.setOri(expInfo['refOrientation'] + thisIncrement)
#draw all stimuli
foil.draw()
target.draw()
fixation.draw()
win.flip()
core.wait(0.5) #wait 500ms; but use a loop of x frames for more accurate timing in fullscreen
# eg, to get 30 frames: for f in xrange(30): win.flip()
#blank screen
fixation.draw()
win.flip()
#get response
thisResp=None
while thisResp==None:
allKeys=event.waitKeys()
for thisKey in allKeys:
if thisKey=='left':
if targetSide==-1: thisResp = 1#correct
else: thisResp = -1 #incorrect
elif thisKey=='right':
if targetSide== 1: thisResp = 1#correct
else: thisResp = -1 #incorrect
elif thisKey in ['q', 'escape']:
core.quit() #abort experiment
event.clearEvents() #must clear other (eg mouse) events - they clog the buffer
#add the data to the staircase so it can calculate the next level
staircase.addData(thisResp)
dataFile.write('%i,%.3f,%i\n' %(targetSide, thisIncrement, thisResp))
core.wait(1)
#staircase has ended
dataFile.close()
staircase.saveAsPickle(fileName) #special python binary file to save all the info
#give some output to user in the command line in the output window
print 'reversals:'
print staircase.reversalIntensities
print 'mean of final 6 reversals = %.3f' %(numpy.average(staircase.reversalIntensities[-6:]))
#give some on screen feedback
feedback1 = visual.TextStim(win, pos=[0,+3],
text='mean of final 6 reversals = %.3f' %
(numpy.average(staircase.reversalIntensities[-6:])))
feedback1.draw()
fixation.draw()
win.flip()
event.waitKeys() #wait for participant to respond
win.close()
core.quit()
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