Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 17, 2013
Last Modified: January 10, 2026 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a Paced Motor Timing procedure; a measure of an individual's ability to synchronize voluntary movements with an external stimulus, such as auditory beeps. It is used to evaluate temporal processing, coordination, and motor timing.
The implemented procedure is similar to the by Wittman et al (2007).
Wittmann, M., Leland, D.S., Jan Churan, J. & Paulus, M.P.(2007). Impaired time perception and motor timing in stimulant-dependent subjects. Drug and Alcohol Dependence, 90, 183–192.
6 minutes
participants are asked to synchronize keyboard clicks with a steady pacer signal of equally spaced beeps.
In condition A: pacer signal (beep) is played for all test trials. In condition B: pacer signal (beep) is only played in the beginning.
taps in this script are accepted before or after a beep is played.
- 2 pacing conditions (paced vs. unpaced) x 3 Stimulus Onset Asynchronies (SOAs: 1000ms, 2000ms, 4000ms)
- paced vs. unpaced tested in blocked format with paced conditions running first
- SOAs are sampled randomly within the pacing conditions
Paced Condition:
In the Paced Conditions deviations from the pacer signal are recorded. These deviations can occur
before or after the beep signal. Only the last 10 tap intervals are considered for summary variables
- all trials can collect multiple spacebar presses to enable the collection of synchronized beeps
that happend before the beep is played
The script records the timestamp of the beep as well as the timestamp of each response made in the raw datafile.
Algorithm for SYNCHRONIZATION analysis:
- the script looks at the last 10 beeps and tries to match up each of these beeps with the closest (non matched)
spacebar response that was made within (beepTimeStamp - SOA/2) to (beepTimeStamp + SOA/2)
- the scripts calculates the absolute difference between the beepTimeStamp and matched responseTimeStamp: abs(beepTimeStamp-responseTimeStamp)
- if no adequate response match is found for a beep, the script substitutes (SOA/2) for the calculated difference
- the script calculates the mean of the 10 time differences: (theoretical Range: 0-SOA/2)
Algorithm for TAP INTERVAL analysis:
- the script looks at all responses made during the TARGET-TIME-INTERVAL: (timestamp of first of the last 10 beeps - SOA/2) TO (timestamp of last of the last 10 beeps + SOA/2)
- the script then calculates all the tap intervals from all responses made during that time frame
as differences in timestamps of these responses
Example: tapInterval1 = responseTimeStamp2-responseTimeStamp1
- the script calculates the mean of all these tap intervals
the more responses were made during the TARGET-TIME-INTERVAL,
the more intervals are used for the calculation of the mean
Unpaced Condition:
In the unpaced condition, only Response Tap Intervals are recorded and only for the
last 10 tap intervals (in the summary data file).
If only a subset of the conditions should be run, go to section Experiment and follow instructions.
see section Editable Stimuli
see script pacedmotortiming_instructions_inc.iqjs
File Name: pacedmotortiming_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 |
Parameter Settings |
|
| reps | Number of test trials (default: 20) the start beep does not count towards this number |
| validReps | Number of paced/unpaced trials used for summary statistics (default: the last 10 pacers/trials) in condition B, the pacer signal does not play anymore for these trials |
| soa1 | SOA 1 in ms (default: 1000ms) => SOA = Stimulus Onset Asynchrony |
| soa2 | SOA 2 in ms (default: 2000ms) |
| soa3 | SOA 3 in ms (default: 4000ms) |
Paced Trials (Condition A), Separately For Soa1-Soa3 |
|
| nrResponsesCondASoa1 | Number of all registered spacebar presses for Condition A ("paced") with soa1 (for all 20 beeps) |
| targetIntervalTapResponsesASoa1 | The number of tap responses made during the TARGET-TIME-INTERVAL Considered for the analysis of tap intervals are all tap responses that are registered from TARGET-TIME-INTERVAL = (timestamp of first of 10 last beeps) - (SOA/2) TO (timestamp of last of 10 last beeps) + (SOA/2) |
| extraTapResponsesASoa1 | The number of extra tap responses (beyond 10) during TARGET-TIME-INTERVAL |
| meanTICondASoa1 | Mean Tap Interval (TI) (time intervals between taps). |
| errorTICondASoa1 | Difference (in ms) btw. mean TI and SOA |
| relErrorTICondASoa1 | Relative TI error (relative to SOA) |
| stdTICondASoa1 | Associated standard deviation of tap intervals |
| cvTICondASoa1 | Coefficient of Variation (CoV) = (sd/mean)*100 => relative measure of variability |
| pacedResponseCountCondASoa1 | Number of matched responses for the last 10 beeps for Condition A ("paced") with soa1 that are used to calculate 'meanToACondA-soa1' (Range: 0-10). If this number is lower than 10, not all beeps were successfully paired with a spacebar press. |
| meanToACondASoa1 | Mean TapOnsetAsynchrony (ToA) for conditionA for soa1; based on the last 10 (default) beeps matched with the closest (non matched) response within the time interval: beepTimeStamp +/- (SOA/2) => DIRECTIONAL mean deviation from pacer beep (negative ) if a beep remains unmatched, (SOA/2) is substituted in for the time difference between beepTimeStamp and responseTimeStamp for the purpose of the script's synchronicity analyses => Maximum of meanToACondASoa1 = (SOA/2) |
| meanAbsoluteErrorCondASoa1 | ABSOLUTE mean deviation from pacer beep for soa1; based on the last 10 (default) beeps => ABSOLUTE ERROR measure |
| stdAbsoluteErrorCondASoa1 | Associated standard deviations of absolute errors |
Unpaced Trials (Condition B), Separately For Soa1-Soa3 |
|
| nrResponsesCondBSoa1 | Counts all responses made during the Unpaced Condition (counts responses across paced and unpaced trials) |
| unpacedResponseCountCondBSoa1 | Counts number of unpaced responses (should be 10) |
| meanTICondBSoa1 | Mean Tap Interval (time intervals between taps) in ms based on the last 10 (default) intervals for ConditionB ('unpaced') with soa1 |
| errorTICondASoa1 | Difference (in ms) btw. mean TI and SOA |
| relErrorTICondASoa1 | Relative TI error (relative to SOA) |
| stdTICondBSoa1 | Associated standard deviation of tap intervals |
| cvTICondBSoa1 | Coefficient of Variation (CoV) = (sd/mean)*100 => relative measure of variability (relative to mean) |
File Name: pacedmotortiming_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 | 1 = pacer signal present until the end 2 = pacer signal stops after a predetermined number of trials (here:10) |
| conditionCounter | Counts the number of blocks run in the paced (1) and unpaced (2) conditions |
| reps | Stores the number of pacer repetitions for the current block |
| soa | Stores the SOA for the current block |
| countbeeps | Counts the number of beeps played |
| sound.beep.timestamp | The timestamp of the current beep (measured from script onset) |
| responseTimeStampsPerBeep | The timestamp(s) of the spacebar responses made in one (beep-)trial for unpaced trials this will always be 1 |
| countResponsesTrial | A counter variable that counts all registered responses during a trial |
| responseCounter | Counts all responses made during a block (should be 20) |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Design |
||
| reps | Number of test trials the start beep does not count towards this number | 20 |
| validReps | Number of paced/unpaced trials used for summary statistics in condition B, the pacer signal does not play anymore for these trials | 10 |
Timing Parameters |
||
| soa1 | SOA 1 in ms => SOA = Stimulus Onset Asynchrony | 1000 |
| soa2 | SOA 2 in ms | 2000 |
| soa3 | SOA 3 in ms | 4000 |
| maxAsynchrony | Maximum absolute deviation in ms from pacer that that is considered a synchronous response | 120 |
| getReadyDuration | The duration (in ms) of the get-ready trial | 3000 |