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					DIFFERENCE THRESHOLD: ADJUSTMENT METHOD (Example: determine difference threshold for a red)
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 01-20-2014
last updated: 01-08-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 01-08-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This script implements the ADJUSTMENT METHOD to estimate the difference threshold for a particular color red

Reference: 
Ehrenstein, W.H. & and Addie Ehrenstein, A. (1999). Psychophysical Methods. In U. Windhorst & H. Johansson, Hakan (Eds.), 
Modern Techniques in Neuroscience Research (pp.1211-1241). Heidelberg: Springer.
(->http://uni-leipzig.de/~isp/isp/history/texts/PSYPHY-M.PDF)


											  *Task*
Participants are asked to adjust a red Target color until the red color of the Target is as red as the given
red Base color. Adjustments are made with keyboard input (D = decrease red target color; L =  increase red target color)


DATA FILE INFORMATION: 
The default data stored in the data files are:

(1) Raw data file: 'AdjustmentMethod_raw*.iqdat' (a separate file for each participant)

build:							Inquisit build
computer.platform:				the platform the script was run on
date, time, subject, group:		date and time script was run with the current subject/groupnumber 
blockcode, blocknum:			the name and number of the current block
trialcode, trialnum: 			the name and number of the currently recorded trial
									(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
/adjustcycles:					stores the number of adjustment cycles run

/baseline_value:				stores the color of the current base
/target_value:					stores the color of the current target
/direction:						1 = Down (sequence starts with targetvalue > baseline value)
								2 = Up (sequence starts with targetvalue < baseline value)

/sequencecount:					counts how many adjustment sequences have been run	
response:						the participant's response
latency: 						the response latency in ms
						
/DiffThreshold_up:				the estimated Difference threshold for the current UP sequence (= starting with
								target value < baseline value)
/DiffThreshold_down:			the estimated Difference threshold for the current DOWN sequence (= starting with
								target value > baseline value)
/TotalDiffThreshold:			mean difference threshold for one adjustment cycle (up and down)

(2) Summary data file: 'AdjustmentMethod_redcolor_summary*.iqdat' (a separate file for each participant)

script.startdate:			date script was run
script.starttime:			time script was started
script.subjectid:			subject id number
script.groupid:				group id number
script.elapsedtime:			time it took to run script (in ms)
computer.platform:				the platform the script was run on
/completed:					0 = script was not completed; 1 = script was completed (all conditions run)

/step:						the decrease in target value everytime participants adjusts (default: 1)
/adjustcycles:				stores the number of adjustment cycles run						
/baselinevalue1:			the default baseline value for the first adjustment cycle
/DiffThreshold1:			mean difference threshold for the first adjustment cycle (both up and down)


EXPERIMENTAL SET-UP
	
By default this scripts estimates the Difference Thresholds for 1 Base color (-> editable values), 
with 2 sequences (one where the targets starts out lighter and one where the target starts out darker, 
order randomly determined).
The thresholds are the red color components of the target when participants decide that they are the same (aka press 'ENTER').
The overall threshold is the mean of the "up" and "down" thresholds.

INSTRUCTIONS
see section Editable Instructions

EDITABLE CODE:
check below for (relatively) easily editable parameters, stimuli, instructions etc. 
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code to further customize your experiment.

The parameters you can change are:

/baselinevalue1:					the baseline red value for the first adjustment cycle
									(0 -> black, 255 -> brightest red)
									Note: to add adjustment cycles with different basevalues
									add a value for each new baseline value you want to test and go to
									BLOCKS for further instructions.

/step:								the decrease in target value everytime participants adjusts (default: 1)
/initialdifference:					initial difference in the red component of target and base (default: 50)						

/interadjustmentpause:				pause after an adjustment sequence (default: 500ms)

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