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Number Bisection Task
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 09-06-2018
last updated: 02-25-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 02-25-2022 Millisecond Software
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BACKGROUND INFO
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This script implements the Number Bisection Task based on:
Nuerk, H., Geppert, B., van Herten, M., & Willmes, K. (2002). On the impact of
different number representations in the number bisection task. Cortex, 1,
691–715.
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TASK DESCRIPTION
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Participants view a series of triplets of numbers (e.g. 5-7-9), each presented for max.3s,
and have to decide whether the center number is the arithmetic mean of the flanking numbers.
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DURATION
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The default set-up runs appr. 45 minutes
Practice block: 32 trials => appr. 3 minutes
Test block: 72 trials => appr. 7 minutes
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DATA FILE INFORMATION
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The default data stored in the data files are:
(1) Raw data file: 'numberbisectiontask_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)
date, time: date and time script was run
subject, group: with the current subject/groupnumber
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 such as feedback trials. Thus, trialnum
may not reflect the number of main trials run per block.
blockcount: block count (for test blocks only)
trialcount: number of test trials run in the current block
bisectionality: 1 = bisectional; 2 = non-bisectional
multiplicativity: for bisectional problems only:
1 = multiplication triplets from a number sequence (e.g. 2-4-6, 14-21-28);
2 = otherwise (e.g. 3-8-13)
bisectionTaskRange: for bisectional problems only:
1 = difference btw. the target numbers ('outer numbers') is btw. 2-8 (e.g. 4-7-10 => 10-4 = 6)
2 = difference btw. the target numbers ('outer' numbers) is btw. 12-18 (e.g. 4-12-20 => 20-4 = 16)
bisectionPossibility: for non-bisectional problems only:
1 = the actual arithmetic mean of the target numbers (=mean of first and third number) is an integer (e.g. 4-8-10; (4+10)/2 = 7)
2 = otherwise (e.g. 4-7-9 => (4+9)/2 = 6.5)
distance: for non-bisectional problems only:
1 = the absolute difference btw. the actual mean of the target numbers (=mean of first and third number)
and the provided arithmetic mean (= the second number) is 0.5-1.5 (e.g. 3-6-7; (3+7)/2=5; 6-5 = 1)
2 = the absolute difference btw. the actual mean of the target numbers (=mean of first and third number)
and the provided arithmetic mean (= the second number) is 2-8 (e.g. 12-18-20; (12+20)/2=16; 18-16 = 2)
stimulusitem: the presented number triplet
response: scancode of response button (0 = no response)
18 = E => yes
23 = I => no
resp: "yes" vs. "no" vs " " (empty = no response)
correct: accuracy of response: 1 = correct response; 0 = otherwise
latency: the response latency (in ms); measured from: measured from: onset of number triplets
(2) Summary data file: 'numberbisectiontask_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)
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)
Note: mean response times are based on correct responses with latencies >= 200
propCorrect_practice: proportion correct during practice
meanRT_practice: mean response time of correct responses during practice
propCorrect_bisectional_multi_small: proportion correct responses for bisectional, 'multiplication-triplets' problems with a small task range
meanRT_bisectional_multi_small: mean response time (in ms) of correct responses for bisectional, 'multiplication-triplets' problems with a small task range
propCorrect_bisectional_multi_wide: proportion correct responses for bisectional, 'multiplication-triplets' problems with a wide task range
meanRT_bisectional_multi_wide: mean response time (in ms) of correct responses for bisectional, 'multiplication-triplets' problems with a wide task range
propCorrect_bisectional_nonmulti_small: proportion correct responses for bisectional, 'non-multiplication-triplets' problems with a small task range
meanRT_bisectional_nonmulti_small: mean response time (in ms) of correct responses for bisectional, 'non-multiplication-triplets' problems with a small task range
propCorrect_bisectional_nonmulti_wide: proportion correct responses for bisectional, 'nonmultiplication-triplets' problems with a wide task range
meanRT_bisectional_nonmulti_wide: mean response time (in ms) of correct responses for bisectional, 'non-multiplication-triplets' problems with a wide task range
propCorrect_nonbisectional_possible_near: proportion correct responses for nonbisectional, 'possible mean' problems with a near distance of suggested mean to actual mean
meanRT_nonbisectional_possible_near: mean response time (in ms) of correct responses for nonbisectional, 'possible mean' problems with a near distance of suggested mean to actual mean
propCorrect_nonbisectional_possible_far: proportion correct responses for nonbisectional, 'possible mean' problems with a far distance of suggested mean to actual mean
meanRT_nonbisectional_possible_far: mean response time (in ms) of correct responses for nonbisectional, 'possible mean' problems with a far distance of suggested mean to actual mean
propCorrect_nonbisectional_impossible_near: proportion correct responses for nonbisectional, 'impossible mean' problems with a near distance of suggested mean to actual mean
meanRT_nonbisectional_impossible_near: mean response time (in ms) of correct responses for nonbisectional, 'impossible mean' problems with a near distance of suggested mean to actual mean
propCorrect_nonbisectional_impossible_far: proportion correct responses for nonbisectional, 'impossible mean' problems with a far distance of suggested mean to actual mean
meanRT_nonbisectional_impossible_far: mean response time (in ms) of correct responses for nonbisectional, 'impossible mean' problems with a far distance of suggested mean to actual mean
* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions
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EXPERIMENTAL SET-UP
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1. Practice: 32 trials
* 16 bisectional triplets (range: 2-18); 16 non-bisectional triplets (range: 2-18)
* triplets presented randomly
* performance feedback provided for 1000s
Trial Sequence:
* presentation of triplets: max. 3000ms (terminates with response)
* feedback for 1000ms
* interstimulus interval of 1.5s in between triplets (presents a fixation cross)
(Note: the SOA during practice is variable due to the feedback presentation)
2. Test:
* 5 Blocks of 72 trials each = 360 trials total
* each blocks runs 9 trials of each of the 8 possible trials
(trial.bisectional_multi_small...trial.nonbisectional_impossible_far)
* order of trials is selected randomly (as is the selection of the triplets)
* no feedback
Trial Sequence:
* A new triplet appears with a stimulus onset asynchrony (SOA) of 4.5s
* each triplet is presented for max. 3s (= response window)
* interstimulus interval of min. 1.5s in between triplets (presents a fixation cross)
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STIMULI
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Test Triplets: This script uses the 360 triplets provided by Nuerk et al (2002)
the size can be fine-tuned under section Editable Parameters
Practice Triplets: the practice triplets are novel triplets generated by Millisecond Software (none of the practice
triplets are used during the test)
- half of the practice triplets (16) are bisectional triplets (range: 2, 4, 6, 8, 10, 12, 18; two of each)
- half of the practice triplets (16) are non-bisectional triplets (range: 2, 4, 6, 8, 10, 12, 18; two of each)
all triplets can be edited under section Editable Stimuli
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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:
/numberOfPracticeTrials: the number of practice trials to run (default: 32)
Notes:
(1) the number should be divisible by 2
(2) for numbers > 32, triplets will be repeated
(3) for numbers < 32, the randomly selected ranges of the triplets (range = difference btw. outer numbers)
might not be balanced across bisectionable and non-bisectionable triplets
To get a balanced number of ranges, consider reducing the appropriate item lists under
section Editable Stimuli (item.practice_bisect; item.practice_nonbisect)
/numberOfTestBlocks: the number of test blocks to run (default: 5); each testblocks runs 72 trials
Notes:
(1) for numbers > 5, triplets will be repeated
(2) for numbers < 5, randomly chosen triplets will not be the same across participants.
To get the same triplets for all participants, consider reducing the appropriate item lists under
section Editable Stimuli.
/stimPresentationTime: maximum stimulus presentation time in ms (default: 3000ms) => response window
/ISI: minimum interstimulus interval in ms (default: 1500ms)
Note: a new triplet appears every 4.5s (SOA= 3000ms + 1500ms)
/minLatency: the minimum response time that is considered a valid response time (default: 200ms)
/stimSize: the proportional size of the triplets (relative to canvas) (default: 7%)
/fixationSize: the proportional size of the fixation cross (relative to canvas) (default: 7%)
Responsekeys: see Tools -> Keyboard Scancodes
/responsekey_yes: the 'yes' response button (here: "E"); left response key
/responsekey_no: the 'no' response button (here: "I"); right response key
Note: for this script to operate correctly on touchscreen devices,
the 'yes' response key should be located left to the 'no' key.
