Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Millisecond thanks Dr. Christian Stahl for collaborting on this script!
Created: January 07, 2016
Last Modified: January 05, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
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
25 minutes
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').
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)
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
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)
• 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 are not original to Stahl et al - they are provided by Millisecond
in the form of html pages. You can edit these files in simple word editors such as Notepad (Windows) or
TextEdit (Mac).
File Name: recentprobestask_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| startDate | Date the session was run |
| startTime | Time the session was run |
| subjectId | Participant ID |
| groupId | Group number |
| sessionId | Session number |
| elapsedTime | Session duration in ms |
| completed | 0 = Test was not completed 1 = Test was completed |
| runFixedSetup | True = a fixed order of trials with fixed memory is used ( the trial order is provided by Stahl et al, 2014) false = order of trials is random and memory sets are created on the fly 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) |
File Name: recentprobestask_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockCode | Name of the current block |
| blockNum | Number of the current block |
| trialCode | Name of the current trial |
| trialNum | Number of the current trial |
| runFixedSetup | True = a fixed order of trials with fixed memory sets/probes is used ( 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 ( 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 |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| runFixedSetup | True = a fixed order of trials with fixed memory is used ( 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 | 1500ms |
| memorySetDuration | The duration (in ms) of the memory set presentation in ms | 2000ms |
| retentionInterval | The duration (in ms) of the retention interval in ms | 300ms |
| readyDuration | The duration (in ms) of the get ready trial | 5000ms |
| leftKey | The left response button (here: "E") | |
| rightKey | The right response button (here: "I") 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 | 8% |
| letterSize | The size of the letters in proportion to the canvas height | 8% |