Return to the Recent Probes Task page
						
										RECENT PROBES TASK
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 11-07-2016
last updated: 04-19-2017 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright © 04-19-2017 Millisecond Software

Millisecond Software thanks Dr. Christian Stahl for collaborting on this script!


BACKGROUND INFO 

											*Purpose*
This script implements the Recent Probes Task based on:


Stahl, C.; Voss, A.; Schmitz, F.; Nuszbaum, M.;
Tüscher, O.; Lieb, K.; Klauer, K.C. (2014). Behavioral components of impulsivity
Journal of experimental psychology: General, Vol.143(2), pp.850-86


											  *Task*
Participants see a 2x3 matrix of 6 letters (= memory set) for 2s. After an additional 3s, a probe letter is presented and
participants have to decide whether this letter was part of the memory set or not.
In half the trials (match or nonmatch), the presented probes were part of the memory set of the preceding trial ('recent probe'), in the
other half of the trials the probe hadn't been presented (neither as a letter of the memory set nor as a probe) during 
the last 3 preceding trials ('nonrecent probe').
  


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

(1) Raw data file: 'recentprobestask_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) 
/runFixedSetup:					true = a fixed order of trials with fixed memory sets/probes is used (Note: the trial order is provided by Stahl et al, 2014) - default setting of this script
								false = order of trials is random and memory sets are created on the fly (Note: each block runs 3 prefatory trials + 28 test trials)
/probeType:						"recent" vs. "nonrecent"
/matchType:						"match" vs. "nonmatch"
/letter1-
/letter6:						stores the letters for the 6 letter memory set (from upper left to lower right)
/currentMemorySet:				stores the 6 letters of the current memory set
/probe:							stores the probe letter
/probePosition:					stores the probe position in the memory set (0 = probe was not part of the memory set)
response:						the participant's response (scancode of response key)
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency (in ms)


(2) Summary data file: 'recentprobestask_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)
/runFixedSetup:					true = a fixed order of trials with fixed memory sets/probes is used (Note: the trial order is provided by Stahl et al, 2014) - default setting of this script
								false = order of trials is random and memory sets are created on the fly (Note: each block runs 3 prefatory trials + 28 test trials)
/RecentProbeScore:				difference in proportion correct between recent and nonrecent nonmatch trials
								(positive difference => indication that using a (nonmatching) probe from a recent memory set interfered with performance)

* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions


EXPERIMENTAL SET-UP

1. Practice Block: 
	* 10 trials (5 match vs. 5 nonmatch)
	* order randomly determined
	
Testblocks:	2 matchTypes (match vs. nonmatch) x 2 probeType (recent vs. nonrecent), tested within-subjects

match: probe is a member of the current memory set
nonmatch: probe is not a member of the current memory set
recent: probe is a letter from the memory set of the previous trial
nonrecent: probe letter has not been used during the 3 preceding trials (it was neither a member of the memory sets nor a probe)

2. 5 Test Blocks:
(A) fixed set-up (default setting in this script): 
	* the script runs 5 blocks with a fixed trial order, fixed memory sets, fixed probes and fixed
		probe positions. The fixed set up was provided by Stahl et al (2014)
	* Each test block runs 28 trials (7 per trialtype) => a total of 35 trial per trialtype

(B) random set-up: 
	* 3 start trials randomly selected from match vs. nonmatch trials (trials are excluded from summary analyses)
		Note: the test blocks runs three trials that cannot be "nonrecent" trials yet (see definition of non-recent below),
		the actual test trials can be any of the 4 trialtypes	
	* 28 trials (match_recent, match_nonrecent, nonmatch_recent, nonmatch_nonrecent) => 35 trials per trialtype
	* order of trialtypes is randomly determined
	Note: probe selection constraint: the probe of one trial cannot repeat the probe of the preceding trial

Trial set-up:
fixation (1500ms) -> memory set (2000ms)-> fixation (3000ms) -> probe (until response)-> {negative feedback (500ms)} -> next trial 


Main DV: 
/RecentProbeScore:		difference in proportion correct between recent and nonrecent nonmatch trials
						(positive difference => indication that using a (nonmatching) probe from a recent memory set might interfere with performance)


STIMULI
* 20 consonants from the English alphabeth (black on gray background)
* current memory set is selected randomly without replacement for each trial
* letters are replaced after each trial into the letter selection pool
* location of probe letter in memory sets is randomly determined

INSTRUCTIONS
instructions are not original to Stahl et al - they are provided by Millisecond Software LLC
in the form of html pages. You can edit these files in simple word editors such as Notepad (Windows) or
TextEdit (Mac).

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:
/runFixedSetup:					true = a fixed order of trials with fixed memory is used (Note: the trial order is provided by Stahl et al, 2014)
								false = order of trials is random and memory sets are created on the fly 


/fixationDuration:				the duration of the initial fixation cross in ms (default: 1500ms)
/memorySetDuration:				the duration of the memory set presentation in ms (default: 2000ms)
/retentionInterval:				the duration of the retention interval in ms (default: 300ms)

/leftKey:						the scancode of the left response button (here: 18)
/rightKey:						the scancode of the right response button (here: 23)
/leftKeyLabel:					the corresponding left key label (here: E)
/rightKeyLabel:					the corresponding right key label (here: i)
Note: the key assignment to match/nonmatch is done under section EXPERIMENT. By default, the left response key is the 
match key and the right response key is the nonmatch key.

/fixationSize:					the size of the fixation cross in proportion to the canvas height (default: 8%)
/letterSize:					the size of the letters in proportion to the canvas height (default: 8%)


Copyright © Millisecond Software. All rights reserved.
Contact | Terms of Service | Security Statement | Employment