Script Author: David Nitz (dave@millisecond.com), Millisecond
Last Modified: January 27, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements the learning experiment by Karpicke & Roediger (2008). The study focuses on the effects of repeated studying (encoding) and repeated testing (retrieval) on short and long term retention of knowledge (in this case: the acquisition of foreign language vocabulary). In their experiment they contrasted a classic learning condition with three different 'drop out' conditions in which words that were previously recalled perfectly were dropped from further study conditions but not necessarily from further testing.
Karpicke, J. D. & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319, 966-968.
40 minutes
This is a learning experiment. Participants are presented a total of 40 Swahili-English word pairs one at a time. Subjects are required to learn these items so that they are able to recall the correct English translation given the Swahili word. There are a total of 4 study and 4 test periods and an intermittent distracter task. There are four experimental conditions:
(1) ST Subjects study the whole list of 40 items in each study period. Subjects are tested on the whole list of 40 items in each test period.
(2) SnT Subjects study only those items they have not recalled previously. Subjects are tested on the whole list of 40 items in each test period.
(3) STn Subjects study the whole list of 40 items in each study period. Subjects are tested only on those items they have not recalled previously.
(4) SnTn Subjects study only those items they have not recalled previously. Subjects are tested only on those items they have not recalled previously.
• 4 different experimental conditions:
(1) ST
Subjects study the whole list of 40 items in each study period.
Subjects are tested on the whole list of 40 items in each test period.
(2) SnT
Subjects study only those items they have not recalled previously.
Subjects are tested on the whole list of 40 items in each test period.
(3) STn
Subjects study the whole list of 40 items in each study period.
Subjects are tested only on those items they have not recalled previously.
(4) SnTn
Subjects study only those items they have not recalled previously.
Subjects are tested only on those items they have not recalled previously.
• Two Sessions (1 week apart): Session ID is entered at start of script together with Subject and Group id
(1) Initial: four study-distractor-test periods of 40 Swahili-English word pairs;
Phase ends with participants predicting their performance in the follow-up session
(2) Follow-up: a single test period is completed one week after the initial session.
see section Editable Stimuli
see section Editable Instruction
File Name: karpickeroediger2008_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| 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 |
| condition | The assigned experimental condition as collected at task onset: 1=ST, 2=SnT, 3=STn, 4=SnTn. |
| taskPhase | Name of the current task phase ("study phase", "test phase", "math phase", "delayed test phase"). |
| trialCount | Number of trials run in the current study or test period. |
| nCorrect | Number of correct responses in the current test period. |
File Name: karpickeroediger2008_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockcode | The name the current block (built-in Inquisit variable) |
| blocknum | The number of the current block (built-in Inquisit variable) |
| trialcode | The name of the currently recorded trial (built-in Inquisit variable) |
| trialnum | The number of the currently recorded trial (built-in Inquisit variable) trialnum is a built-in Inquisit variable; it counts all trials run even those that do not store data to the data file. |
| condition | The assigned experimental condition as collected at task onset: 1=ST, 2=SnT, 3=STn, 4=SnTn. |
| taskPhase | Name of the current task phase ("study phase", "test phase", "math phase", "delayed test phase"). |
| response | The participant's entered response |
| resptoLower | Converts participants' typed answers to lowercase in order to ensure accurate but not overly strict scoring of correct and incorrect responses. |
| correct | The correctness of the response (1 = correct; 0 = incorrect) |
| error | 1 = error; 0 = no error |
| numCorrect | Running total of correct responses in the current block |
| latency | The response latency (in ms) for openended responses: measured until "next" box is clicked |
| openended.testTrial.firstCharLatency | Latency (in ms) measured until input of first character |
| openended.testTrial.lastCharLatency | Latency (in ms) measured until input of last character |
| trialCount | Number of trials run in the current study or test period. |
| nCorrect | Number of correct responses in the current test period. |
| itemNumber | Holds the unique itemnumber of the currently selected pair. Used for proper item selection and validation, scoring, etc. |
| itemstate | Encodes whether a given item is active (1) or inactive (0) in the current study or test period (-> 'trial.itemselect', 'list.studystate','list.teststate'). |
| swahili | The currently used Swahili word of the tested word pair |
| english | The currently used English word of the tested word pair |
| text.mathProblem.currentItem | The currently presented math problems |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| studyTimeout | Display duration during study trials. Default: 5000 ms. | 5000 |
| testTimeout | Timeout for test trials. Default: 8000 ms. | 8000 |
| delayedTestTimeout | Timeout for the delayed test trials (2nd session). Default: 15000 ms. | 15000 |
| distracterTimeout | Global timeout for the distracter block. Default: 30000 ms. | 30000 |
| posttrialDelay | Variable posttrial delay for study and test trials. Default: 500 ms. | 500 |
| debugmode | 1 = debuginfo is displayed on screen 0 = script runs in testmode; no debuginfo is displayed | 0 |