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Line Bisection Task
(German instructions)
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 01-16-2023
last updated: 11-04-2024 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 11-04-2024 Millisecond Software
German translations provided by K. Borchert for Millisecond Software
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BACKGROUND INFO
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This script implements Millisecond Software'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.
References:
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
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TASK DESCRIPTION
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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.
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DURATION
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the default set-up of the script takes appr. 3 minutes to complete
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DATA OUTPUT DICTIONARY
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The fields in the data files are:
(1) Raw data file: 'lineBisectiontask_raw*.iqdat' (a separate file for each participant)
build: The specific Inquisit version used (the 'build') that was run
computer.platform: the platform the script was run on (win/mac/ios/android)
computer.touch: 1 = the screen is a touchscreen; 0 = otherwise
date, time: date and time script was run
subject: with the current subject id
group: with the current group id
session: with the current session id
blockCode, blockNum: the name and number of the current block (built-in Inquisit variable)
trialCode, trialNum: the name and number of the currently recorded trial (built-in Inquisit variable)
Note: trialNum is a built-in Inquisit variable; it counts all trials run; even those
that do not store data to the data file.
//built-in DVs:
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 (Note: pixel measures vary from screen to screen)
distanceBtwLinesMM: the distance in mm between the lines (measured from)
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Individual Lines Data
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Note: the final data is provided in trial.Bisection_end
//////Line1//////
line1LengthPct: length of line1 in canvas width percent
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
Note: calculations of mm differences make use of Inquisit's built in conversion functions
(same for the remaining lines)
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//line failure data:///
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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)
(2) Summary data file: 'lineBisectiontask_summary*.iqdat' (a separate file for each participant)
inquisit.version: Inquisit version run
computer.platform: the platform the script was run on (win/mac/ios/android)
computer.touch: 1 = the screen is a touchscreen; 0 = otherwise
startDate: date script was run
startTime: time script was started
subjectId: assigned subject id number
groupId: assigned group id number
sessionId: assigned session id number
elapsedTime: time it took to run script (in ms); measured from onset to offset of script
completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
//////Summary Data//////
numberOfLines: the number of lines to be bisected
////overall/////
numberErrors: number of Error placements
//Note: 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)
//individual line summary data:////
//Negative values: the marker was placed left to the midpoint
//Calculations of mm differences make use of Inquisit's built in conversion functions
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)
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
(same for line2-line14)
Note: data fields will be empty for lines that are not run
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EXPERIMENTAL SET-UP
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(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.
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STIMULI
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provided by Millisecond Software - 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.
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INSTRUCTIONS
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provided by Millisecond Software - can be edited under section 'Editable Instructions'
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EDITABLE CODE
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check below for (relatively) easily editable parameters, stimuli, instructions etc.
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code
to further customize your experiment.
The parameters you can change are:
//color parameter
/ canvasColor = lightGray //Display color of the actively used portion of the screen (the 'canvas')
//Note: if set to a color other than the screencolor, the active canvas
//appears 'anchored' on the screen regardless of monitor size
/ screenColor = lightGray //Color of the screen not used by the canvas ('inactive screen')
/ defaultTextColor = black //Default color of text items presented on active canvas
//CANVAS SIZING PARAMETERS
//sizing Parameters in RELATIVE measurements relative to CANVAS HEIGHT
//NOTE: to run the script with ABSOLUTE screen measurements, go to 'defaults' and set
//canvasSize to absolute measurements
/ lineHeightPct = 2% //the proportional height (to canvas HEIGHT) of each line
//Line Lengths (relative to canvas WIDTH):
//Note: if you change the lengths of the lines, you may have to change their midpoints as well as otherwise
//not the entire line might be presented (if there is a problem with placements, the script will let you know)
/ line1LengthPct = 30% //the proportional length (to canvas WIDTH) of line1 (Note: the default width is 192mm based on set canvasheightMM, so line1 = 30%*192mm = 57.6mm long)
/ line2LengthPct = 45% //the proportional length (to canvas width) of line2
/ line3LengthPct = 70% //the proportional length (to canvas width) of line3
/ line4LengthPct = 90% //the proportional length (to canvas width) of line4
/ line5LengthPct = 85% //the proportional length (to canvas width) of line5
/ line6LengthPct = 55% //the proportional length (to canvas width) of line6
/ line7LengthPct = 50% //the proportional length (to canvas width) of line7
/ line8LengthPct = 50% //the proportional length (to canvas width) of line8
/ line9LengthPct = 50% //the proportional length (to canvas width) of line9
/ line10LengthPct = 50% //the proportional length (to canvas width) of line10
/ line11LengthPct = 50% //the proportional length (to canvas width) of line11
/ line12LengthPct = 50% //the proportional length (to canvas width) of line12
/ line13LengthPct = 50% //the proportional length (to canvas width) of line13
/ line14LengthPct = 50% //the proportional length (to canvas width) of line14
//Note: if 14 lines are run, the placement of the done button
//may have to be adjusted depending on length and placement of line14
//canvas width = 100% (left side of canvas: 0% to 100%: right side of canvas)
/ line1MidxPct = 30% //midpoint horizontal coordinate of line1 relative to canvas width
/ line2MidxPct = 25% //midpoint horizontal coordinate of line2 relative to canvas width
/ line3MidxPct = 60% //midpoint horizontal coordinate of line3 relative to canvas width
/ line4MidxPct = 53% //midpoint horizontal coordinate of line4 relative to canvas width
/ line5MidxPct = 43% //midpoint horizontal coordinate of line5 relative to canvas width
/ line6MidxPct = 65% //midpoint horizontal coordinate of line6 relative to canvas width
/ line7MidxPct = 30% //midpoint horizontal coordinate of line7 relative to canvas width
/ line8MidxPct = 30% //midpoint horizontal coordinate of line8 relative to canvas width
/ line9MidxPct = 30% //midpoint horizontal coordinate of line9 relative to canvas width
/ line10MidxPct = 30% //midpoint horizontal coordinate of line10 relative to canvas width
/ line11MidxPct = 30% //midpoint horizontal coordinate of line11 relative to canvas width
/ line12MidxPct = 30% //midpoint horizontal coordinate of line12 relative to canvas width
/ line13MidxPct = 30% //midpoint horizontal coordinate of line13 relative to canvas width
/ line14MidxPct = 30% //midpoint horizontal coordinate of line14 relative to canvas width
//Note: if 14 lines are run, the placement of the done button
//may have to be adjusted depending on length and placement of line14
/ numberOfLines = 6 //number of lines to run (max = 14)
//Note: if you run fewer than 14 lines, you can throw out the
//unnecessary data columns under section 'data' to reduce 'data clutter'
/ placementMethod = "mouse" //choose "mouse", "stylus" or "finger"
//tells participants how to place the marker (preferrably)
//Note: on touchscreens, participants will be able to use fingers regardless
/ takeScreenshot = false //true (1): a screenshot of the final marker placement is taken
//false (0): no screenshot is taken
/////Debug/////
/ runDebugMode = false //true (1): the script presents the mid points on each line
//false (0): the script does not present the mid points (testmode)
