Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 05, 2014
Last Modified: January 04, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script runs an Inspection Time task; a task used to study the early stages of visual processing. The implemented task is based on Deary et al (2004).
Deary, I.J., Enrico Simonotto, E., Meyer, M., Marshall, A., Ian Marshall, I., Goddard, N. & Wardlawf, J.M. (2004). The functional anatomy of inspection time: an event-related fMRI study. NeuroImage, 22, 1466– 1479.
18 minutes
Participants see stimuli that have one long and one short arm. The stimuli are presented for variable durations before they are covered by a mask. Participants have to decide whether the long arm was left or right and press corresponding response keys. Participants are told that reaction time is unimportant.
(1) 15 stimulus presentation durations tested with 20 repetitions (default).
Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms
on a monitor with a vertical refresh rate = 160Hz
Note that monitors with a vertical refresh rate of 60Hz don't refresh the screen often enough
and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum)
to refresh the screen (thus 17ms is the minimum that can be used on 60Hz monitors).
(set durations under section EDITABLE CODE -> Editable Values)
(2) The stimuli duration times are selected randomly without replacement (method of constant stimuli).
(3) The long arm is located on the left for 50% of the trials
(4) Practice block for 25 randomly durations (number of trials can be edited)
Stimuli are provided by Millisecond. They can be replaced under
section EDITABLE CODE -> Editable stimuli.
The target stimulus was created in such a way, that the long arm is twice the length
of the short arm (which equals the length of the crossbar)
The size of the target stimulus in this script is coded in terms of canvas screen %.
In order to achieve, a size that is roughly equal to the one used by Deary et al (2004),
go to stim picture.stim and follow instructions.
Instructions are provided by Millisecond in the form of htm pages.
Instructions can be edited directly in file "IT_intro.htm"
or replaced entirely.
File Name: inspectiontimetask_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 |
| display.refreshRate | The vertical refresh rate of the current monitor Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz Note that monitors with a vertical refresh rate of 60Hz don't refresh the screen often enough and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum) to refresh the screen (thus 17ms is the minimum that can be used on 60Hz monitors). |
| 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 |
| propcorrectStim1 | Proportion correct responses for stim duration 1 (here: 6ms) - the same for all 15 stim durations |
File Name: inspectiontimetask_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 |
| display.refreshRate | The vertical refresh rate of the current monitor Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz Note that monitors with a vertical refresh rate of 60Hz don't refresh the screen often enough and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum) to refresh the screen (thus 17ms is the minimum that can be used on 60Hz monitors). |
| 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. |
| countTrials | Counts all stim trials |
| stimDuration | Duration (in ms) of current stim stimduration_condition1-15 (depending on stimduration) |
| location | 1 = right long arm; 2 = left long arm |
| stimulusItem | The presented stimuli in order of trial presentation |
| response | The participant's response (scancode of response buttons) 30 = A 38 = L |
| correct | Accuracy of response: 1 = correct response; 0 = otherwise |
| latency | The response latency (in ms); measured from: onset of stims |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Design Parameters |
||
| trialsPerDuration | Number of trials per stimulusduration if that number is changed, list.stimdurations/list.stimduration_condition (section Editable Lists) need to be changed accordingly => 15 stimdurations x 20 trials/stimduration = 300 trials total | 20 |
| nrPracticeTrials | Number of practice trials in this script. the durations are selected at random. | 25 |
Sizing Parameters |
||
| stimPicHeightPct | Default height (in screen height %) Deary et al (2004): long arm = 5cm (short arm and cross bar = 2.5cm) you can set the height of the stim directly under element picture.stim | 26% |
| cueFontSizePct | Default height (in screen height %) of the cue | 10% |
Timing Parameters |
||
| readyDuration | Duration in ms of get-ready-trial | 2000 |
| cueDuration | Duration of cue in ms | 500 |
| cueIsi | Cue(offset)-stim(onset) Interstimulus Interval in ms | 600 |
| maskDuration | Duration of mask in ms | 500 |
| iti | Inter trial interval in ms (measured from response to onset of cue) | 500 |
Stimulus Presentation Durations (In Ms) - Final Presentation Duration Will In Part Depend On The Display's Vertical Refreshrate |
||
| stimDuration1 | 6 | |
| stimDuration2 | 12 | |
| stimDuration3 | 19 | |
| stimDuration4 | 25 | |
| stimDuration5 | 31 | |
| stimDuration6 | 37 | |
| stimDuration7 | 44 | |
| stimDuration8 | 50 | |
| stimDuration9 | 62 | |
| stimDuration10 | 75 | |
| stimDuration11 | 87 | |
| stimDuration12 | 100 | |
| stimDuration13 | 125 | |
| stimDuration14 | 150 | |
| stimDuration15 | 200 | |
Response Keys |
||
| responseKeyLeft | Left response key (on QWERTY keyboard) | "A" |
| responseKeyRight | Right response key (on QWERTY keyboard) | "L" |