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									MONETARY INCENTIVE DELAY TASK
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 08-28-2015
last updated: 10-11-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 10-11-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This script implements the Monetary Incentive Delay Task as described in:

Knutson, B., Westdorp, A., Kaiser, E., & Hommer, D. (2000). FMRI visualization of brain activity during a monetary 
incentive delay task. Neuroimage, 12(1), 20-27


											  *Task*
Participants are asked to respond to a brief target shape that follows 2 different cues: one an incentive cue (e.g. an orange shape)
and the other a nonincentive cue (e.g. a blue shape).
Responses to nonincentive targets (aka targets following nonincentive cues) never have an impact on money gained 
or money lost; nevertheless participants receive verbal feedback whether they were fast enough or not. 
Responses to incentive targets have different consequences depending on three different reward conditions: Control vs. Reward vs. Punishment.

In the Reward condition, participants who respond fast enough to a target that follows an incentive cue get a monetary reward (e.g. $1).
If they are not fast enough, no money is won.
In the Punishment condition, participants who respond fast enough to a target that follows an incentive cue do not lose any money (e.g. $1).
If they fail to respond in time, they lose money (e.g. $1).
In the control condition, there is no difference between incentive and nonincentive targets. Participants can neither win any money,
nor can they lose any.


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

(1) Raw data file: 'MonetaryIncentiveDelayTask_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
 /order:						'reward->punish' vs. 'punish->reward'
blockcode, blocknum:			the name and number of the current block
/exp_condition:					0 = control condition; 1 = Reward condition; 2 = Punishment Condition
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) 
/incentive_condition:			1 = incentive; 2 = nonincentive
/delayduration:					the current delay duration in ms
/targetduration:				the current target duration in ms (also the response window)
stimulusitem:					the presented stimuli in order of trial presentation (only static elements)
response:						the participant's response (here: scancode of response button)
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency (in ms)
/total_control:					the total earned in control condition
/total_reward:					the total earned in reward condition
/total_punishment:				the total earned in punishment condition

(2) Summary data file: 'MonetaryIncentiveDelayTask_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)
/order:							'reward->punish' vs. 'punish->reward'
/total_control:					the total earned in control condition
/total_reward:					the total earned in reward condition
/total_punishment:				the total earned in punishment condition
/propCorrect_IncentiveReward:		proportion correct for incentive trials in the reward condition
/propCorrect_NonIncentiveReward:	proportion correct for nonincentive trials in the reward condition
/propCorrect_IncentivePunishment:	proportion correct for incentive trials in the punishment condition
/propCorrect_NonIncentivePunishment:proportion correct for nonincentive trials in the punishment condition
/propCorrect_IncentiveControl:		proportion correct for incentive trials in the control condition
/propCorrect_NonIncentiveControl:	proportion correct for nonincentive trials in the control condition	
	
EXPERIMENTAL SET-UP

3 conditions: Control vs. Reward vs. Punishment, tested within in a blocked design.
All participants start with the Control condition. 
The assignment to Reward -> Punishment vs. Punishment -> Reward is counterbalanced by groupnumber
(odd groupnumbers start with Reward; even groupnumbers start with Punishment)

In each condition: 
- 100 trials
	- 20 incentive trials
	- 80 nonincentive trials
	=> The order is randomized with the constraint that incentive trials cannot be presented consecutively
- the color for incentive/nonincentive trials is different for each condition

Trial Sequence (6000ms):
cue (500ms) -> random delay* (4000-4500ms)-> target (variable, duration = 60th percentile RT)** -> Feedback (500ms) -> ITI (variable to round trial sequence duration to ~6s)

*Random Delay: is controlled by list.delay under section Editable Lists
**Target Durations: in this script, the targetduration is set to the 60th percentile RT as assessed during baseline ~ 60% correct performance
Knutson et al (2000) report to have used targetdurations beween 160ms and 260ms (p.21)
Note: if the 60th percentile > 500ms the script aborts automatically (500ms is the max. possible target duration given all other default trial durations)

STIMULI
cues/targets: squares (size can be controlled via parameters.stimsize under section Editable Values)
targets: white in all conditions
Control: incentive cue: red; nonincentive cue: green
Reward: incentive cue: orange; nonincentive cue: blue
Punishment: incentive cue: yellow; nonincentive cue: pink

INSTRUCTIONS
are not original to Knutson et al (2000) - they can be edited under section Editable Instructions

EDITABLE CODE:
check below for (relatively) easily editable values, 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 values you can change are:


/responsekey:				the scancode of the response key (default: 57 = Spacebar; check Tools-> keyboard scancode for different options)
/responsekey_label:			the label of the response key (default: Spacebar)
/cueduration:				the duration of the cue in ms (default: 500)
/feedbackduration:			the duration of the feedback in ms (default: 500)
/trialduration:				the duration of a complete trial sequence in ms (default: 6000)
/Reward_win:				the number of points ($) won in the Reward condition (default: 1)
/Punishment_loss:			the number of points ($) lost in the Punishment condition (default: 1)
/punishment_startamount:	the amount of money provided at the beginning of the punishment condition (default: 20)
/reward_startamount:		the amount of money provided at the beginning of the reward condition (default: 0)
/control_startamount:		the amount of money provided at the beginning of the control condition (default: 0)
/stimsize:					the size  of the cues/targets as percentages of canvas height (default: 10%)
/presenttotal:				true = present the "Total earned" throughout Reward and Punishment Blocks.
							false = does not present the "Total earned" throughout Reward and Punishment Blocks.


Note: the expressions under Editable values can be changed to change the 10 targetdurations.

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