Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: October 07, 2015
Last Modified: February 24, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a variant of the Brown-Peterson Trigram Task inspired by:
Brown, J. (1958). Some tests of the decay theory of immediate memory. Quarterly Journal of Experimental Psychology, 10, 12-21.
Peterson, L. R. & Peterson, M. J. (1959). Short-term retention of individual verbal items. Journal of Experimental Psychology, 58, 193–198.
25 minutes
Participants are presented a consonant trigram (e.g. TRD) for 1500ms (default - can be edited) They are instructed to study the trigram for a potential recall test later on. To prevent rehearsal, participants are then presented a random 3 digit number and are asked to count backwards from it by 3s as long as prompted (number of prompts depends on delay between offset of trigram and onset of recall box; by default each prompt is presented for 1000ms and default delays are 3000-18000ms). Half the trials ask participants to enter the last number they were prompted to count backwards to, the other half the trials ask participants to enter the trigram.
=> 2 (recall type) x 6 delays (measured from offset of trigram to onset of textbox = foil task duration)
1.Instruction/Demo Block: runs one trial sequence with additional instructions (timing is different from actual trials)
-> can be repeated
2. Practice Block: runs 6 trials by default (same trial timings as in actual test; change number of trials under section BLOCK block.practice)
3. Test Block
• 1 Block of 48 trials (default; the number of trials can be edited under block.trigrams under section BLOCKS)
=> half the trials result in a trigram recall (Target Trials), half the trials result in a last number recall (Foil Trials)
=> default delays (measured from offset of trigram to onset of recall box): 3000, 6000, 9000, 12000, 15000, 18000ms
Trial Sequence:
Trigram (default: 1500ms) -> start 3-digit number (default: 1000ms)->{prompts; each for 1000ms}*-> recall textbox (either last number or trigram recall) -> Feedback
• no voice records are recorded during the count trial; the first prompt is to REPEAT the start 3-digit number
Trigrams: randomly assembled of 3 consonants (except y) - no repeats of consonants within the same trigram
-> no repeats of Trigrams (possible for trialCount < 500 only)
Number: randomly selected 3 digit number
-> no repeats of starting number (possible for trialCount < 500 only)
presented in black on white
Size can be edited under Editable Parameters
Instructions are not original. They are provided by Millisecond and can be edited under Editable Instructions.
File Name: consonantTrigramtask_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 |
| totalCorrectLastNumber | Counts all correctly entered last numbers across task |
| meanCorrLastNumber | Calculates the proportion of correctly entered last numbers |
| totalCorrectConsonants | Counts all correctly recalled consonants (consonant position important) across task |
| meanCorrConsonants | Calculates the mean number of correctly recalled consonants per trial |
File Name: consonantTrigramtask_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 |
| countTrials | TrialCounter (resets after practice) |
| recallType | 1 = trigram recall; 2 = last number |
| delay | Stores the current delay between offset of trigram and onset of textbox |
| stimulusItem | The presented stimuli in order of trial presentation |
| response | The participant's response |
| correct | The correctness of the response (1 = correct; 0 = incorrect) |
| latency | The response latency (in ms) Note * for trial.trigram/trial.lastnumber the latency reflects the duration of the trial from onset of trigram to offset of the last prompt (parameters.trigramduration + values) * for openended trials the latency is measured from onset of textbox to selecting the next button |
| startNumber | Stores the first (start) number |
| lastNumber | Stores the number last prompted to count down to |
| correctLastNumber | Sums up all the correctly counted last numbers per trial |
| totalCorrectLastNumber | Counts all correctly entered last numbers across task |
| trigram | Stores the current trigram |
| correctConsonants | Sums up all correctly recalled consonants (position important) per trial |
| totalCorrectConsonants | Counts all correctly recalled consonants (consonant position important) across task |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| trigramDuration | The presentation duration (in ms) of the trigrams | 1500 |
| promptDuration | The presentation duration (in ms) of the counting prompts the promptduration needs to be in synch with the delays (see list.trigram_delays) promptdurations < 1000 require additional changes on the trial level | 1000 |
| feedbackDuration | The duration of the accuracy feedback (in ms) | 2000 |
| iti | The intertrial interval (in ms) | 3000 |
| trigramDurationDemo | The presentation duration (in ms) of the trigrams during the demo | 5000 |
| promptDurationDemo | The presentation duration (in ms) of the counting prompts during the demo | 5000 |
| countby | Counts backwards by 3' | 3 |