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									Money / Food Delay Discounting Task
SCRIPT INFO

Script Author: David Nitz for Millisecond Software
last updated: 01-07-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 01-07-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
	This script implements the Money/Food Delay Discounting Task as described in:
	
	Odum, A.L., Baumann, A.A.L., Rimington, D.D. (2006). Discounting of delayed hypothetical money and food: 
	Effects of amount. Behavioural Processes, 73, 278-284.



											  *Task*
Participants are asked to select btw. 2 options: one option presents a higher value but with a delay (7 different ones),
the second option presents a lower value but with an immediate pay-off. The lower value continuously
decreases or increases (decrease/increase tested in blocked format).
The options tested are 'Money' and 'Food'.


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

(1) Raw data file: 'DDT_MoneyFood_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 
								group:	assigned group:
									1: Money-> Food, desc -> asc
									2: Money-> Food, asc->desc
									3: Food -> Money, desc -> asc
									4: Food -> Money, asc -> desc
blockcode, blocknum:			the name and number of the current block
values.blockcount:				The number of blocks run
values.blocktype:				Type of current block: “money” or “food”
values.order:					Current order of values "descending" vs “ascending”
values.trialcount:				Discounttrials run in 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) 
response:						Participant’s response (choice trials: ‘delayed’ or ‘immediate’)
latency:						Response latency for the current trial in ms
values.delay:					The currently selected delay
parameters.delayedreward:			The set amount for a delayed reward ($10)
values.immediatereward:			The currently selected immediate reward
values.delayedresponsestreak:	Tracks the number of consecutive delayed responses per block
values.immediateresponsestreak:	Tracks the number of consecutive immediate responses per block
values.ip_desc:					The indifference point found in the descending blocks of a consecutive pair of money/food blocks for a given delay
values.ip_asc:					The indifference point found in the ascending blocks of a consecutive pair of money/food blocks for a given delay
values.ip:						The overall estimated indifference point of a pair of money/food blocks: average of the ip_asc and ip_desc of a consecutive pair of money/food blocks for a given delay


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

script.startdate				Date script was run
script.starttime				Time script was run
script.subjectid				Subject number
script.groupid:					Group number
								group:	assigned group:
									1: Money-> Food, desc -> asc
									2: Money-> Food, asc->desc
									3: Food -> Money, desc -> asc
									4: Food -> Money, asc -> desc
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)
parameters.delayedreward:		The set amount for a delayed reward ($10)
/ip_delay1_M-
/ip_delay7_F:					the IPs for the 7 different delays for food (F) and money (M) blocks


EXPERIMENTAL SET-UP
2 options (food, money: tested in blocked format) x 2 orders (ascending, descending: tested in blocked, consecutive format) x 7 delays (tested in blocked format, in ascending order);
tested within subjects

4 different experimental groups (assignment by groupnumber)
									1: Money-> Food, desc -> asc 
									2: Money-> Food, asc -> desc
									3: Food -> Money, desc -> asc
									4: Food -> Money, asc -> desc

Indifference Point Calculations:
For each of the 7 temporal delays 2 indifference points are assessed: one for ascending order and one for descending order.
Indifference points are reached when participants switches response pattern 'consistently':
-> descending order: after 2 choices of the delayed option
-> ascending order: after 2 choices of the immediate option
The final indifference point for a delay is the midpoint of these 2.
	
STIMULI
see section EDITABLE STIMULI

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:

/ pretrialdelay:					pretrialpause (default: 0ms)
/ posttrialdelay:					posttrialpause (default: 500ms)
/ delayedreward:					the default value to use for the delayed reward (here: $10.00)

/delay1-
/delay7:							the proposed 7 delays tested
									(defaults: "1 day", "2 days", "1 week", "2 weeks", "1 month", "6 months", "2 years")


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