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*RECENT PROBES TASK*
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 11-07-2016
last updated: 02-28-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 02-28-2022 Millisecond Software
Millisecond Software thanks Dr. Christian Stahl for collaborting on this script!
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BACKGROUND INFO
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This script implements the Recent Probes Task, a memory task for measuring proactive
interference.
The implemented procedure is 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
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TASK DESCRIPTION
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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').
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DURATION
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the default set-up of the script takes appr. 25 minutes to complete
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DATA FILE INFORMATION
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The default data stored in the data files are:
(1) Raw data file: 'recentprobestask_raw*.iqdat' (a separate file for each participant)*
build: The specific Inquisit version used (the 'build') that was run
computer.platform: the platform the script was run on (win/mac/ios/android)
date, time: date and time script was run
subject, group: with the current subject/groupnumber
session: with the current session id
blockcode, blocknum: the name and number of the current block (built-in Inquisit variable)
trialcode, trialnum: the name and number of the currently recorded trial (built-in Inquisit variable)
Note: trialnum is a built-in Inquisit variable; it counts all trials run; even those
that do not store data to the data file such as feedback trials. Thus, trialnum
may not reflect the number of main trials run per block.
(parameter) 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 key response (scancode of response key)
18 = E (left)
23 = I (right)
57 = spacebar
0 = no response
responseCategory: interpreted key response: "match" vs. "nonmatch"
correct: the correctness of the response (1 = correct; 0 = incorrect)
latency: the response latency (in ms); measured from onset of probe
(2) Summary data file: 'recentprobestask_summary*.iqdat' (a separate file for each participant)*
inquisit.version: Inquisit version run
computer.platform: the platform the script was run on (win/mac/ios/android)
startDate: date script was run
startTime: time script was started
subjectid: assigned subject id number
groupid: assigned group id number
sessionid: assigned session id number
elapsedTime: time it took to run script (in ms); measured from onset to offset of script
completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
(parameter) 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
Note: each block runs 3 prefatory trials that are not considered for data analysis
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
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EXPERIMENTAL SET-UP
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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 testtrials (7 per trialtype) => a total of 35 trial per trialtype + 3 prefatory trials
(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)
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STIMULI
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* 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
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INSTRUCTIONS
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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).
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EDITABLE CODE
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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 (in ms) of the initial fixation cross in ms (default: 1500ms)
/memorySetDuration: the duration (in ms) of the memory set presentation in ms (default: 2000ms)
/retentionInterval: the duration (in ms) of the retention interval in ms (default: 300ms)
/readyDuration: the duration (in ms) of the get ready trial (default: 5000ms )
/leftKey: the left response button (here: "E")
/rightKey: the right response button (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%)
