Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Last Modified: January 07, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a basic letter n-back procedure with face emotion flankers. The n-back task is a go/nogo working-memory performance task with increasing levels of difficulty.
The implemented procedure is based on:
Ladouceur, C. D., Silk, J. S., Dahl, R. E., Ostapenko, L., Kronhaus, D. M., & Phillips, M. L. (2009). Fearful faces influence attentional control processes in anxious youth and adults. Emotion, 9(6), 855-864. https://dx.doi.org/10.1037/a0017747
The script uses the general framework of the Inquisit Letter N-back script based on: Ragland, J.D., Turetsky, B.I., Gur, R.C, Gunning-Dixon, F., Turner, T, Schroeder, L., Chan, R., & Gur, R.E. (2002).Working Memory for Complex Figures: An fMRI Comparison of Letter and Fractal n-Back Tasks. Neuropsychology, 16, 370-379.
Adjustments to z-scores as recommended by: Gregg, A. & Sedikides, C. (2010). Narcissistic Fragility: Rethinking Its Links to Explicit and Implicit Self-esteem, Self and Identity, 9:2, 142-161 (p.148)
30 minutes
In the 1-key single n-back task, participants are shown a sequence of stimuli (here: a sequence of white letters on a black background) and are asked to indicate whether the currently presented stimulus fulfills the following criteria:
For N=0 trials: - is the letter the same as the letter 'M'? If so (it's a target), and press "A". If not, don't respond.
For N=1 trials: - is the letter the same as the one that preceded it? If so (it's a target), and press "A". If not, don't respond.
For N=2 trials: - is the letter the same as the one presented two trials before? If so (it's a target), and press "A". If not, don't respond.
Etc. for increasing levels of N
During test trials, the center letters are flanked by: - happy faces - fearful faces - neutral faces - no faces
Practice:
- After instructions, participants work through 1 block of each
- 0-back; 2-back (currently the settings are set to run them in sequence starting with a 0-back)
- default: 9 trials with 3 target trials; 6 nontarget trials
- default: feedback is presented during practice
Test:
- 8 blocks: 2 level of N (0,2) x 4 flanker conditions (no faces, happy faces, fearful faces, neutral faces)
- 3 runs of those 8 blocks:
• each run starts with condition N=0, no faces (see parameters.startRunWith_0backNoFaces)
• remaining 7 blocks are randomly selected
- each block runs 12 trials (+ starttrials that cannot display targets yet) => 4 target trials; 8 non-target trials
- The computer selects randomly
a) whether it is a target trial or not and
b) what letter to show if it is not a target trial
Trial Information:
- Each trial presents the letter for max. 500ms
- An intertrial interval (displays a fixation cross) replaces the center letter.
Duration is randomly selected from duration starting at 3000ms to 4000ms (steps 100ms) with a mean duration of 3500 (see Editable lists)
- the response window can be set under section Editable Parameters.
CURRENTLY it's set to max.3000ms
Face Flanker Selection:
Face stimuli are selected randomly without replacement from the current pool of face stimuli for each condition.
Repeats within one block are possible after all possible stims have been selected.
The pool of available images is reset after each block.
stimuli from NimStim set available at
www.macbrain.org (Tottenham et al., 2009)
female participants: 2, 5, 6, 7, 8, 9, 13, 14, 18, and 19;
male participants: 21, 23, 24, 27, 28, 30, 33, 37, 41, and 42) taken from the .
All images are 800 x 600 pixels and cropped into an oval shape
(all open mouthed expressions)
The current script runs with placeholders (but uses the file names of the appropriate NimStims)
provided by Millisecond - can be edited under section Editable Instructions
Instructions are not original to the task. They are provided by Millisecond
as htm pages and simple page elements and can be edited either by changing
the provided html files or directly under Editable Instructions.
in order for the instructions to reflect alternative parameter settings,
some of the conditionalized code used in the htm files can be found in the script itself.
File Name: emotion_singlenbacktask_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 |
| round | The total number of experimental blocks run the following summary variables are only based on performance on trial.target/trial.nontarget (excludes trial.start even if parameters.excludeStartTrialfromPerformanceMeasure = false) |
| propCorrect | Overall proportion correct (across all test blocks) |
| meanHitRT | Overall mean correct response time (in ms); is equal to the overall mean hit response time z-score calculations: adjustments (see Gregg & Sedikides, 2010, p.148) If the hit rate FA rate is 0 => 0.005 is used instead (aka 0.005 is added to the hitFA rate) IF the hit rate FA rate is 1.0 => 0.995 is used instead (aka 0.005 is subtracted from the hitFA rate) |
| targetTrialCounter | The absolute number of target trials (across all test blocks) |
| hitRateOverall | Overall hit rate (across all test blocks) = hitting 'A' for targets |
| missRateOverall | Overall miss rate (across all test blocks) = NOT hitting 'A' for targets |
| meanHitRT | Overall mean hit response time (in ms; across all test blocks) |
| nontargetTrialCounter | The absolute number of nontarget trials (across all test blocks) |
| faRateOverall | Overall False Alarm/Commission Error Rate (across all test blocks) = hitting 'A' for nontargets |
| crRateOverall | Overall correct rejection rate (across all test blocks) = NOT hitting 'A' for nontargets |
| meanFART | Overall mean False Alarm response time (in ms; across all test blocks) |
| zHitRateOverall | The z-score of the overall hit rate |
| zFaRateOverall | The z-score of the overall False Alarm rate |
| dPrimeOverall | Computes d' (parametric measure of sensitivity) The higher the value, the better targets were overall correctly distinguished from nontargets (d' = 0: chance performance; negative values: nontargets were treated as targets and targets were treated as nontargets) |
| cOverall | C-criterion in signal detection:The absolute value of c provides an indication of the strength of the response bias/response style negative: participant more likely to report that signal (go stims) is present (liberal response style) may favor faster responding in speed-accuracy trade-off response paradigms positive: favoring caution (conservative response style) The following variables look at the different levels of N. If a level of N was not run, the variables will store return "not run" |
| hitRateN0NoFaces | Hit rate (hitting 'A' for targets) for level N = 0, no faces |
| missRateN0NoFaces | Miss rate for level N = 0, no faces |
| hitRTN0NoFaces | Mean hit response time (in ms) for level N = 0, no faces |
| crRateN0NoFaces | Correct rejection rate for level N = 0, no faces |
| faRateN0NoFaces | False Alarm/Commission Error Rate (hitting 'A' for nontargets) for level N = 0, no faces |
| zHitRateN0NoFaces | The z-score of the hit rate for level N = 0, no faces |
| zFaRateN0NoFaces | The z-score of the False Alarm rate for level N = 0, no faces |
| dPrimeN0NoFaces | Computes d' (parametric measure of sensitivity) The higher the value, the better targets were overall correctly distinguished from nontargets (d' = 0: chance performance) for level N = 0, no faces |
| cN0NoFaces | C-criterion for level N = 0, no faces (same for Level N=0-2, noFaces, happy, fearful, neutral) |
File Name: emotion_singlenbacktask_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, group, | With the current subject/groupnumber |
| 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 |
| phase | "practice" vs "test" |
| round | Counts the number of test rounds (1 round = 8 blocks) run |
| blockPerRound | The number of test blocks run within a round |
| n | The current level N tested |
| emotion | 0 (no faces); 1 (happy); 2 (fearful), 3 (neutral) |
| startTrialCounter | Keeps track of how many start trials have been run |
| stimulusItem.1 | The presented letter |
| flankerStim | The image file of the current flanker image |
| currentTarget | The item number of the current target |
| response | The Response of the participant (scancode of response button) 0 = no response 31 = 'A' key (positive response) |
| responseCategory | "Hit" vs. "Omission Error" vs. "CorrReject" vs. "Commission Error" |
| correct | The correctness of the response (1 = correct; 0 = otherwise) |
| latency | How fast a participant responded within the given timeframe, if at all (in ms) no responses = the entire trialduration |
| list.blockAcc.mean | Proportion correct during the current block (start trials are excluded from block acc assessment by default, editable) |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| allowPracticeRepeat | True: practice can be repeated as often as indicated (default) false: practice cannot be repeated | |
| excludeStartTrialfromPerformanceMeasure | True (1): performance during start trials that cannot be targets yet is not considered for Block level performance analyses, e.g. for feedback purposes (default) false (0): performance during start trials that cannot be targets yet IS considered for block performance analyses (default) | |
| startRunWith0BackNoFaces | True: each test round starts with 0back-no faces (default) false: the different conditions are randomly sampled for each test round | |
| stimulusPresentationTime | The presentation time (in ms) of the stimuli | 500ms |
| startFixation | The duration (in ms) of the fixation cross that is presented at the start of each block | 3500ms |
| rw | Max. response window (in ms) after onset of center letter the response window cannot be longer than stimulus presentation time (500) + shortest ITI (3000) | 3000ms |
| letterSize | Proportional letter size | |
| fixationCrossSize | Proportional fixation cross size | |
| picSize | Proportional size of the flanker images | |
| flankerLetterSize | Proportional size of the flanker letters | |
| flankerLeft | Proportional position of the left flanker | |
| flankerRight | Proportional position of the right flanker | |
| debugmode | Debugmode = 1: targetalerts are shown on screen, debugmode = 0, no targetalerts are shown (default) (in general: if levels of N are changed, adjustments need to be made to instructions and list.Nlevel) | 0 |