Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 22, 2020
Last Modified: January 10, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a Probabilistic Serial Reaction Time Task. The implemented procedure is based on Kaufman et al (2010)
Kaufman, S.B et al (2010). Implicit learning as an ability. Cognition, 116, 321–340.
25 minutes
Participants are presented 4 gray boxes arranged in a horizontal line and have to press a spatially corresponding response button as fast as possible once one of the boxes turns red. The sequence in which the box positions light up are controlled by two sequences: A and B. 85% of boxes follow sequence A; 15% of boxes follow sequence B. The transition btw. sequences respect the second-order conditionals of the upcoming sequence (see Kaufman et al, 2010, for an indepth discussion). The default task runs 8 test blocks of 120 trials each.
1. Practice: 20 practice trials (change under section Editable Parameters)
- 50% sequence A and 50% sequence B trials
- order is randomly determined
- error feedback is provided
- transitions btw. sequence A trials and sequence B trials respect the second-order conditionals
of the upcoming sequence (Explanation below)
2. Test: by default, this script runs 8 blocks with predetermined sequences of sequenceA and sequenceB trials
(see editable parameters for possible changes)
- each block runs 120 trials
- 85% of the trials are sequence A trials; 15% of trials are sequence B trials
- transitions btw. sequence A trials and sequence B trials respect the second-order conditionals
of the upcoming sequence (see Kaufman et al, 2010, for an indepth discussion)
Example:
sequence A: 1, 2, 1, 4, 3, 2, 4, 1, 3, 4, 2, 3 (see Kaufman et al, 2010)
sequence B: 3, 2, 3, 4, 1, 2, 4, 3, 1, 4, 2, 1 (see Kaufman et al, 2010)
If sequenceA has played the sequence '14' the next position would be '3' IF sequence A continued (14->3).
A switch to sequence B would play position '2' instead as '2' follows '14' in sequence B (14->2).
- after each block participants get a break of 30s (editable parameter)
4 gray boxes - size and screen location can be edited under Editable Parameters
are not original to Kaufman et al (2010); edit under section Editable Instructions
File Name: probabilisticsrt_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 |
| runFixedDesign | True (1): the script ran fixed (pre-determined) trial sequences for block1-block8 false (0): the script ran randomized trial sequences for each block |
| testPropSequenceA | The frequency of test trials in a block for sequence A |
| testPropSequenceB | The frequency of test trials in a block for sequence B practice trials run with 50% seqA/seqB |
Across All Test Blocks |
|
| propCorrectSeqA | Proportion correct responses for sequence A trials |
| meanCorrRTSeqA | Mean correct response time (in ms) for sequence A trials |
| propCorrectSeqB | Proportion correct responses for sequence B trials |
| meanCorrRTSeqB | Mean correct response time (in ms) for sequence B trials |
By Block 1-8 |
|
| propCorrect1SeqA | Proportion correct responses for sequence A trials in block1 |
| meanCorrRT1SeqA | Mean correct response time (in ms) for sequence A trials in block1 (same for block 2-8) |
| propCorrect1SeqA | Proportion correct responses for sequence B trials in block1 |
| meanCorrRT1SeqA | Mean correct response time (in ms) for sequence B trials in block1 (same for block 2-8) |
File Name: probabilisticsrt_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 |
| runFixedDesign | True (1): the script ran fixed (pre-determined) trial sequences for block1-block8 false (0): the script ran randomized trial sequences for each block |
| testPropSequenceA | The frequency of test trials in a block for sequence A |
| testPropSequenceB | The frequency of test trials in a block for sequence B practice trials run with 50% seqA/seqB |
| blockCounter | Counts the number of blocks run (resets after practice) |
| trialCounterPerBlock | Counts the number of trials run in a block |
| sequence | "A" vs. "B": the sequence the current trial is running |
| listIndex | The item index of list.sequenceA/list.sequenceB that is currently selected |
| position | The position of the highlighted box that is selected by listIndex |
Dv |
|
| response | The participant's response (scancode of response buttons) 47 = V; 48 = B; 49 = N; 50 = M 57 = spacebar |
| correct | Accuracy of response: 1 = correct response; 0 = otherwise |
| latency | The response latency (in ms); measured from: onset of highlighted box |