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Millisecond Road Sign Reaction Time Task
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 9-14-2017
last updated: 12-19-2019 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 12-19-2019 Millisecond Software
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BACKGROUND INFO
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This script implements the Millisecond Road Sign Reaction Time Task inspired by the Road Sign Reaction Time Task
described in:
Edwards J., Ross , L.A., Wadley, V.G., Clay, O.J., Crowe, M., Roenker, D.L., Ball, K.K. (2006).
The useful field of view test: Normative data for older adults.
Archives of Clinical Neuropsychology, 21, 275–286.
The Millisecond Road Sign Reaction Time Task can be used with touchscreens OR the mouse.
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TASK DESCRIPTION
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Participants see sets of three or six traffic signs (sets are sampled from four different signs:
left arrow, right arrow, bicycle, pedestrian) that are all crossed out by a red cross.
After a random delay (1000-6000ms, steps of 1000ms), the cross is removed from one of the signs,
and participant has to choose amongst 4 different responses:
- left arrow => move a car icon to the left
- right arrow => move a car icon to the right
- bicycle => press a bicycle stop sign icon
- pedestrian => press a pedestrian stop sign icon
Note: by default, the test is run in a blocked design (N=3 vs. N=6, with N=3 always preceding N=6 block).
To run N=3 and N=6 trials in a randomized mixed design, change parameters.runBlockedDesign under section Editable Parameters.
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DURATION
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the default set-up of the script takes appr. XXX minutes to complete
(if no task duration is provided, please contact Millisecond Software
(katjab@millisecond.com)
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DATA FILE INFORMATION
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The default data stored in the data files are:
(1) Raw data file: 'millisecondroadsigntest_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
script.sessionid: 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.
/runBlockedDesign: true (1): the test is split into 2 blocks: first block runs N=3; second block runs N=6 (default)
false (0): N=3 and N=6 trials are run in a mixed design
/N: stores the current set size tested
/delay: stores the currently randomly sampled target delay in ms (1000-6000ms)
/target: stores the current target image
/distractor1-
/distractor5: store the current distractor images
response: the participant's response (recorded touchscreen/mouse response)
values.responseCategory: description of response:
"left move",
"right move",
"stop-bicycle"
"stop-pedestrian"
correct: accuracy of response: 1 = correct response made after removal of cross; 0 = otherwise
/propCorrect_practice1: proportion initially correct responses during practice 1
/validrt: valid response time (in ms); measured from onset of unslashed target
-> "early response": response was made too early (during practice session 2)
latency: the response latency (in ms) of the last measured response; measured from: onset of stims
/PrematureResponse: number of times participant responded before cross was removed during the current trial
(2) Summary data file: 'millisecondroadsigntest_summary*.iqdat' (a separate file for each participant)*
script.startdate: date script was run
script.starttime: time script was started
script.subjectid: subject id number
script.groupid: group id number
script.elapsedtime: time it took to run script (in ms)
computer.platform: the platform the script was run on
/completed: 0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
/runBlockedDesign: true (1): the test is split into 2 blocks: first block runs N=3; second block runs N=6 (default)
false (0): N=3 and N=6 trials are run in a mixed design
/propCorrect_practice1: the final proportion initially correct responses during practice 1
/aborted: 1 = script was aborted after practice 1; 0 = script was not aborted after practice 1
Note: the following summary variables are based on correct responses made after onset of target
The script considers all correct responses made after onset of target including those trials where a premature response was also registered
/propCorrect_overall: proportion correct across all test trials
/meanRT_overall: mean latency (in ms) of correct responses across all test trials
/propCorrect_3stims: proportion correct across all test trials with N = 3
/meanRT_3stims: mean latency (in ms) of correct responses across all test test trials with N = 3
/propCorrect_6stims: proportion correct across all test trials with N = 6
/meanRT_6stims: mean latency (in ms) of correct responses across all test test trials with N = 6
/sumPrematureResponses: the sum of all premature responses (responses before the cross was removed)
/sumPrematureResponses_3signs: the sum of all premature responses (responses before the cross was removed) in the 3 sign condition
/sumPrematureResponses_6signs: the sum of all premature responses (responses before the cross was removed) in the 6 sign condition
* 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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Note: by default, the test is run in a blocked design (N=3 vs. N=6).
To run N=3 and N=6 trials in a randomized mixed design, change parameters.runBlockedDesign under section Editable Parameters.
1. Response Practice:
- 20 trials that present only 1 sign (5 trials per sign); only correct responses terminate trial
- order of signs is randomized
- if no valid response is detected within 5s, a response reminder (summary of possible responses) is presented on screen
- after the first 20 practice trials, the script checks performance:
if performance is below a cut-off value (default: 90%, see editable parameters.practice1MinACC),the block is repeated
if performance is still below cut-off after the second block (default; see editable parameters.maxPractice1Blocks),
the script aborts.
2. Task Practice:
- 12 trials that run the test set-up but with only 2 signs and with feedback
- each of the four signs is presented as a target 3 times and 3 times as a distractor
- order of targets is randomized
- signs are randomly assigned to two of 12 possible screen locations
- delays (of cross removal) are randomly selected from 1000-6000ms (see list.delays)
3. Test: with N = 3
- 12 trials with sets of 3 signs (no feedback)
- each of the four signs is presented 3 times as a target 3 and 6 times as distractors
- each non-target sign is presented as a distractor twice with each target and never in the same combination:
Example: target left turn
presented with:
1: right turn, bicycle
2: right turn, pedestrian
3: pedestrian, bicycle
- order of trials is randomized
- signs are randomly assigned to three of 12 possible screen locations
- delays (of cross removal) are randomly selected from 1000-6000ms (see list.delays)
5. Test: with N = 6
- 12 trials with sets of 6 signs (no feedback)
- each target is presented 3 times
- !!!Distractor Selection (2 signs in each display have to be repeats):
- distractor 1-3: sample from the non-target options (without replacement)
- distractor 4-5 (repeated signs): sample from all options (without replacement)
=> it's randomly determined whether the target sign is one of the 'double' signs.
=> the frequency of each sign is not controlled for the N=6 trials
- order of trials is randomized
- signs are randomly assigned to six of 12 possible screen locations
- delays (of cross removal) are randomly selected from 1000-6000ms (see list.delays)
6. mixed design block (only run if parameters.runBlockedDesign is turned to false)
- 24 trials: 12 with N=3 and 12 with N = 6, randomized order
Trial Sequence:
fixation cross (until clicked with mouse)-> pretrialpause (default: 1000ms)
-> 3 (6) signs appear, all crossed out -> random delay: 1000-6000ms
-> one cross is removed: target -> waits for response
(Note: responses are collected from onset of stimuli, a valid response terminates the set-up
even if the target has been revealed yet. These trials are noted as "premature responses")
Screen Location of Signs:
- screen locations are randomly sampled from 12 possible screen locations (arranged in a 3 rows x 4 columns matrix)
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STIMULI
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provided by Millisecond Software - can be edited under section Editable Stimuli
The signs are 4 traffic signs commonly used in the United States but can easily be exchanged.
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INSTRUCTIONS
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provided by Millisecond Software as html files.
To edit instructions, edit the html files directly.
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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:
/runBlockedDesign: true (1): the test is split into 2 blocks: first block runs N=3; second block runs N=6 (default)
false (0): N=3 and N=6 trials are run in a mixed design
/minHorizontalChange_px: any horizontal mouse movements (in pixels) smaller than this value is ignored
and not processed as a response (default: 100 pixels).
/picSize: the proportional size of the images (default: 20%)
Note: if picSize is increased list.xcoordinates/list.ycoordinates need to be updated accordingly
/maxPractice1Blocks: the maximum number of response practice blocks run if performance is too low (default: 2)
/practice1MinACC: the minimum proportion correct that terminates practice 1 (response practice)
/pretrialpause: the pause (in ms) after pressing the fixation cross and presentation of signs (default: 1000ms)
/responseReminder: during practice (response learning) a response reminder is presented after this duration (in ms) (default: 5000ms))