Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 16, 2023
Last Modified: January 08, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements Millisecond's computerized version of the Line Bisection Task (e.g. Nash et al, 2010), a behavioral measure of relative cerebral hemisphericity.
Researchers can select to run the task with an absolute screen size to ensure that distances stay the same across devices. The default run proportionally sized stimuli. See section Defaults for more info.
Nash, K., Mcgregor, I., & Inzlicht, M. (2010). Line Bisection as a neural marker of approach motivation. Psychophysiology, 47(5), 979–983. https://doi.org/10.1111/j.1469-8986.2010.00999.x
Jewell, G.,&McCourt, M. E. (2000). Pseudoneglect: A review and metaanalysis of performance factors in line Bisection tasks. Neuropsychologia, 38, 93–110.
Savazzi, S., Posteraro, L., Veronesi, G., & Mancini, F. (2007). Rightward and leftward Bisection biases in spatial neglect: two sides of the same coin? Brain (London, England : 1878), 130(8), 2070–2084. https://doi.org/10.1093/brain/awm143
3 minutes
This task presents up to 14 (staggered) lines on the same page. The number of lines and the length as well as horizontal screen position of each line can be set via parameter settings. By default, this script presents 6 staggered lines of different lengths.
Participants are asked to touch/click the midpoint of each line to place a midpoint marker. Once all lines have been marked, participants can press a 'Done' button. Participants can correct the position of the midpoint markers until they click the 'Done' button. Participants are instructed NOT to measure the lines.
(1) Block: LineCheck
This block checks that the parameter settings for each of the to be presented lines work.
If a violation is detected (e.g. the line is too long for the placement of the midpoint),
the script terminates. The raw data file will contain information about the lines that need to be updated.
(2) Line Bisection Task
1-14 horizontal lines are presented on the same page using the parameter settings for:
- line lengths
- line placements (horizontal midpoints)
The script automatically calculates the vertical distance between the lines depending on how many lines
should be placed on the screne. For Example, if only 1 line is presented it is presented in the
vertical center of the screen.
By default, this script presents 6 of the possible 14 lines.
Participants are asked to place a marker on a each of the lines to bisect them.
All markers have to be placed before a 'Done' button appears.
Participants can correct the marker placements as many times as needed.
provided by Millisecond - number of lines, their length (and width) as well as
horizontal canvas placement can be configured under section Editable Parameters
Absolute Sizing can be achieved by changes under section Defaults.
provided by Millisecond - can be edited in script linebisectiontask_instructions_inc.iqjs
File Name: lineBisectiontask_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 |
| numberOfLines | The number of lines to be bisected |
Overall |
|
| numberErrors | Number of Error placements any pixel difference <> 0 is counted as an error in this script |
| propErrors | Proportion of errors (relative to number of lines) |
| propLeftError | Proportion of left (to midpoint) placed errors (relative to the number of errors made) |
| meanDiffPX | Mean PIXEL difference btw. line midpoints and placed marker |
| meanDiffMM | Mean mm difference btw. line midpoints and placed marker (= pixel mean converted into mm using Inquisit built-in functions) |
Line1-Line14 |
|
| line1LengthPX | Length of line1 in screen pixels |
| line1LengthMM | Length of line1 in mm |
| line1Resps | Number of times the line1 marker was placed |
| line1Diff1PX | PIXEL difference btw. line1 midpoint and placed marker for FIRST marker placed (pixel differences depend on monitor) negative values: the marker was placed left to the midpoint |
| line1DiffFinalPX | PIXEL difference btw. line1 midpoint and placed marker for FINAL marker placed |
| line1MeanDiffPX | Mean pixel difference btw. line1 midpoint and all placed markers on line1 |
| line1Diff1MM | Mm difference btw. line1 midpoint and placed marker for FIRST marker placed (absolute measurements) |
| line1DiffFinalMM | Mm difference btw. line1 midpoint and placed marker for FINAL marker placed (= submitted marker) |
| line1MeanDiffMM | Mean mm difference btw. line1 midpoint and all placed markers on line1 |
File Name: linebisectiontask_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. |
| response | The response of participant (scancode of response button) |
| latency | Response latency (in ms) |
| numberOfLines | The number of lines presented |
| lineHeightMM | The lineHeight in mm |
| distanceBtwLinesPct | The proportional distance (relative to canvas height) between the lines - measured from midpoints |
| distanceBtwLinesPX | The pixel distance of the lines ( pixel measures vary from screen to screen) |
| distanceBtwLinesMM | The distance in mm between the lines (measured from) |
Individual Lines Data - The Final Performance Metrics Is Stored In Trial.Bisection_End |
|
| line1LengthPct | Length of line1 in canvas width percent; same for all remaining lines |
| line1LengthPX | Length of line1 in screen pixels |
| line1LengthMM | Length of line1 in mm |
| line1MidxPct | The horizontal coordinate of the midpoint of line1 in canvas width percent |
| line1MidxPX | The horizontal coordinate of the midpoint of line1 in pixels |
| line1MarkerXPX | The horizontal coordinate of the marker placed on line1 in pixels |
| line1DiffPX | The PIXEL difference (depends on monitor) in horizontal coordinates of line1 and marker Negative values: the marker was placed left to the midpoint |
| line1DiffMM | The mm difference (absolute measurements) in horizontal coordinates of line1 and marker Negative values: the marker was placed left to the midpoint calculations of mm differences make use of Inquisit's built in conversion functions |
Line Failure Data |
|
| lineFailure | 1 = the settings for all to-be-presented lines work; 0 = the settings for at least one line do not work |
| checkLine1 - checkLine14 | Stores the individual notes left for each line (1 = no problem) |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Color Parameter |
||
| canvasColor | Display color of the actively used portion of the screen (the 'canvas') if set to a color other than the screenColor, the active canvas appears 'anchored' on the screen regardless of monitor size | lightGray |
| screenColor | Color of the screen not used by the canvas ('inactive screen') | lightGray |
| defaultTextColor | Default color of text items presented on active canvas | black |
Sizing Parameters |
||
| lineHeightPct | The proportional height (to canvas HEIGHT) of each line | 2% |
Line Lengths (Relative To Canvas Width) |
||
| line1LengthPct | The proportional length (to canvas WIDTH) of line1 | 30% |
| line2LengthPct | The proportional length (to canvas width) of line2 | 45% |
| line3LengthPct | The proportional length (to canvas width) of line3 | 70% |
| line4LengthPct | The proportional length (to canvas width) of line4 | 90% |
| line5LengthPct | The proportional length (to canvas width) of line5 | 85% |
| line6LengthPct | The proportional length (to canvas width) of line6 | 55% |
| line7LengthPct | The proportional length (to canvas width) of line7 | 50% |
| line8LengthPct | The proportional length (to canvas width) of line8 | 50% |
| line9LengthPct | The proportional length (to canvas width) of line9 | 50% |
| line10LengthPct | The proportional length (to canvas width) of line10 | 50% |
| line11LengthPct | The proportional length (to canvas width) of line11 | 50% |
| line12LengthPct | The proportional length (to canvas width) of line12 | 50% |
| line13LengthPct | The proportional length (to canvas width) of line13 | 50% |
| line14LengthPct | The proportional length (to canvas width) of line14 if 14 lines are run, the placement of the done button may have to be adjusted depending on length and placement of line14 | 50% |
Canvas Width = 100% (Left Side Of Canvas: 0% To 100%: Right Side Of Canvas) |
||
| line1MidxPct | Midpoint horizontal coordinate of line1 relative to canvas width | 30% |
| line2MidxPct | Midpoint horizontal coordinate of line2 relative to canvas width | 25% |
| line3MidxPct | Midpoint horizontal coordinate of line3 relative to canvas width | 60% |
| line4MidxPct | Midpoint horizontal coordinate of line4 relative to canvas width | 53% |
| line5MidxPct | Midpoint horizontal coordinate of line5 relative to canvas width | 43% |
| line6MidxPct | Midpoint horizontal coordinate of line6 relative to canvas width | 65% |
| line7MidxPct | Midpoint horizontal coordinate of line7 relative to canvas width | 30% |
| line8MidxPct | Midpoint horizontal coordinate of line8 relative to canvas width | 30% |
| line9MidxPct | Midpoint horizontal coordinate of line9 relative to canvas width | 30% |
| line10MidxPct | Midpoint horizontal coordinate of line10 relative to canvas width | 30% |
| line11MidxPct | Midpoint horizontal coordinate of line11 relative to canvas width | 30% |
| line12MidxPct | Midpoint horizontal coordinate of line12 relative to canvas width | 30% |
| line13MidxPct | Midpoint horizontal coordinate of line13 relative to canvas width | 30% |
| line14MidxPct | Midpoint horizontal coordinate of line14 relative to canvas width if 14 lines are run, the placement of the done button may have to be adjusted depending on length and placement of line14 | 30% |
Design |
||
| numberOfLines | Number of lines to run (max = 14) if you run fewer than 14 lines, you can throw out the unnecessary data columns under section 'data' to reduce 'data clutter' | 6 |
| placementMethod | Choose "mouse", "stylus" or "finger" tells participants how to place the marker (preferrably) on touchscreens, participants will be able to use fingers regardless | "mouse" |
| takeScreenshot | True (1): a screenshot of the final marker placement is taken false (0): no screenshot is taken | false |
Debugging |
||
| runDebugMode | True (1): the script presents the mid points on each line false (0): the script does not present the mid points (testmode) | false |