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									EFFORT EXPENDITURE FOR REWARDS TASK
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 09-28-2015
last updated: 01-11-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 01-11-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This script implements the Effort Expenditure for Rewards Task as described in:

Treadway MT, Buckholtz JW, Schwartzman AN, Lambert WE, Zald DH (2009) Worth the ‘EEfRT’? 
The Effort Expenditure for Rewards Task as an Objective Measure of Motivation and Anhedonia. 
PLoS ONE 4(8): e6598. doi:10.1371/journal.pone.0006598


											  *Task*
Participants have to select between an Easy and a Hard task. Both tasks involve pressing the Spacebar for
a predetermined amount of time. The Hard task offers more money (variable amounts) but is harder and takes 
twice as long. Participants make their selection knowingly under different win probabilities (aka they might
not win money even if they are successful if the win probabilities are low).
By default, E selects the Easy task and I selects the Hard task (can be edited under section Editable Parameters).


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

(1) Raw data file: 'EffortExpenditureforRewardTask_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) 

								Note: by default, only trial.savedata records data to the data file (trial.savedata only records data
								of a completed cycle. If a cycle was started but the test quit because the allotted time was up; that cycle is 
								not recorded anymore and is not counted towards summary data).
								
/practice:						0 = test; 1 = practice
/counttesttrials:				counts the number of completed testtrials
/Reward_easy:					the potential reward assigned to the Easy task (default: "1.00")
/reward_hard:					the currently assigned reward amount for the hard task
/winprobability:				the currently assigned win probability
/selectionresponse:				the key scancode of the selection response
/forced:						1 = the task difficulty was randomly assigned to participant (did not choose themselves)
								0 = participant selected difficulty 
/selecteddifficulty:			the task difficulty chosen/assigned: 1 = easy task; 2 = hard task
/selectedtask:					"easy" vs. "hard"
/selectionrt:					the latency of the selection in ms  (excludes forced choices)
/countpresses:					counts the button presses of the current trial
/finaltaskduration:				the duration (in ms) spent on the task (pressing buttons)
/success:						1 = task was successfully completed; 0 = task was not completed
/win:							1 = the successful completion is rewarded; 0 = the successful completion is not rewarded
/currentreward:					the currently assigned (potential) reward amount for the task chosen
/total:							stores the total of all rewards earned


	
(2) Summary data file: 'EffortExpenditureforRewardTask_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 (prematurely aborted); 1 = script was completed (all conditions run)
/counttesttrials:				counts the number of completed testtrials
/randomwin1:					stores the first randomly selected win amount (in case this is used for an extra incentive)
/randomwin2:					stores the second randomly selected win amount (in case this is used for an extra incentive)
/total:							stores the total of all rewards earned
/counttesttrials:				counts the number of completed testtrials
/count_easy:					counts the number of easy trials (includes forced easy trials)
/count_hard:					counts the number of hard trials (includes forced hard trials)
/countsuccess_easy:				counts the number of successful easy trials
/countsuccess_hard:				counts the number of successful hard trials
/count_forced:					counts the number of times computer had to randomly select a level of difficulty for participant
/meanRT_selection:				mean latency (in ms) of selection (excludes forced selections)
/meantaskduration_E:			mean successful taskduration (pressing button; in ms) of the easy task
/meantaskduration_H:			mean successful taskduration (pressing button; in ms) of the hard task



EXPERIMENTAL SET-UP

(A) Test:
- 20 minutes total
- 3 win probabilities: 88%, 50%, 12% (can be edited under section Editable List; the probabilities are 'true' probabilities and not frequencies)
- hard task reward amounts: $1.24-$4.30 (in steps of $0.01)
- Each level of probability is paired once with with each level of hard task reward value (-> list.rewards_hard) => 921 potential combinations
- The 921 combinations were randomized (see list.rewards_hard) and then are presented to each participant in a fixed order 

Trial Sequence:
Selection Screen (max. 5000ms)*->Ready Screen (1000ms)->Task Screen (max.7s or max.21s)->success/failure feedback screen (2000ms)->potentially win screen (2000ms)

*If no selection is made within 5000ms, the computer randomly selects a task for the participant
	
(B) Practice:
- 4 trials: The first 2 trials provide the choices (Easy->Hard; if something else is chosen, the choice is "corrected");
			for the last 2 trials participants are free to choose either task.
			Reward Amounts for the Hard Task (same as for test) are selected randomly from 4 options (without replacement);
			Win probabilities (same as for test) are randomly selected (with replacement).
			In this script, practice trial provide a reminder description of the tasks for the "Ready" screen (Ready screen is presented for 2000ms)

INSTRUCTIONS
The instructions are not original to Treadway et al (2009). They are provided by Millisecond Software in the form
of simple htm pages (see section Editable Instructions). The htm files can be edited directly.
Use a simple word processor like 'Notepad' to make your edits.

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:

/responsekey_easy:						the scancode of the response key for the Easy selection (default: 18)
/responsekey_easy_label:				the label belonging to the scancode of the response key for the Easy selection (default: E)
/responsekey_hard:						the scancode of the response key for the Hard selection (default: 23)
/responsekey_hard_label:				the label belonging to the scancode of the response key for the Hard selection (default: I)

/Reward_easy:							the potential reward assigned to the Easy task (default: "1.00")

/completetaskduration:					the duration of the completed task in ms (default: 1200000)
/selectionwindow:						the max. response window to make the task selection in ms (default: 5000)
/readyduration:							the duration of the Ready screen in ms (default: 1000)
/easyduration:							the max. duration of the Easy task in ms (default: 7000)
/hardduration:							the max. duration of the Hard task in ms (default: 21000)
/successfeedbackduration:				the duration of the feedback screen regarding success/failure in ms (default: 2000)
/winfeedbackduration:					the duration of the feedback screen regarding the reward money won in ms (default: 2000)

/easypresses:							number of button presses for the Easy task (default: 30)
/hardpresses:							number of button presses for the Hard task (default: 100)

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