Visual Scanning Task

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: January 26, 2014

Last Modified: January 31, 2023 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a Visual Scanning Task; a visual search and recognition task designed to assess Perceptual Speed.

References

UNIFIED TRI-SERVICE COGNITIVE PERFORMANCE ASSESSMENT BATTERY (UTC-PAB) I. DESIGN AND SPECIFICATION OF THE BATTERY. ENGLUND, C.E., REEVES. D.L., SHINGLEDECKER, C.A., THORNE, D.R., WILSON, K.P., & HEGGE. F.W. (1987). REPORT NO. 87-10, NAVAL HEALTH RESEARCH CENTER, P 0 BOX 85122, SAN DIEGO, CALIFORNIA 92138 NAVAL MEDICAL RESEARCH AND DEVELOPMENT COMMAND, BETHESDA, MARYLAND (p.39)

Which was inpired by: Neisser, U. (1963). Decision time without reaction time: experiments in visual scanning. American Journal of Psychology, 76:d376-385.

Duration

10 minutes

Description

Participants are presented with a letter matrix consisting of 25 rows of 5 letters each. The task is to read the matrix from top to bottom, left to right and find the target letter 'K' within 10s (default) and press the Spacebar as soon as the K is found. Row numbers will appear to the right of each row and participants have 4s (default) to type in the row number. Optional feedback can be provided before the next trial sequence is started. If time limits are exceeded, the current trial sequence is terminated, a beep is played, and new trial sequence is started.

Procedure

default set-up:

Practice:
- 1 block of 21 trials (Englund et al, 1987, suggest 10 -> edit parameters.nr_trainingblocks under section 'Editable Values' )

Test:
- 2 (default) blocks or max. 5 min (default), whichever comes first (editable values under section 'Editable Values')
- each block runs 21 trials (target in each of the 21 possible row locations)

Trial Sequence:
(A) trial.fixation: fixation arrow for 500ms (default)
Fixation arrow is presented one field to the left of the first matrix item (it's a preparatory time & location cue)

(B) trial.matrix:
presents 25 rows x 5 column matrix randomly filled with all letters of the alphabet
targetletter: K (only 1 K present in matrix); position is randomly determined with the constraints that it cannot be presented in the first 3 rows and the last row (Englund et al, 1987).
10s (default) to find K
=> press Spacebar (default) when K is found => trial.confirmation_A
=> if K is not found within time frame; a beep is played

(C) trial.confirmation_A/trial.confirmation_B
2-digit row numbers appear to the right of each row and participant is asked to type in the 2-digit row number
(trial.confirmation_A takes in the first number; trial.confirmation_B takes in the second number)
=> max duration: 4s (default); if confirmation is NOT given within 4 s a beep is played and a new trial is started

(D) trial.feedback/trial.beep:
-trial.feedback (optional) presents feedback regarding the performance and the location of K
-trial.beep: presents beep if time limits were exceeded

(E) trial.savetrialdata
stores the trial data of the completely run trial sequence to the data file.

Stimuli

the letters are presented in Courier New (a monospaced font)
Letter size can be adjusted under Editable Parameters if needed.
Letters are white on a black background.

Instructions

Instructions are based on Englund et al (1987).

They are provided by Millisecond in the form of html pages
as htm/html pages and can be edited by changing the provided htm/html files.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).

Summary Data

File Name: visualscanning_summary*.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
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
maxTestBlocks Maximum number of blocks to be run (e.g. 20)
countBlocks Counts the number of test blocks started
remainingTaskTime Stores how much time is left for another block in ms (updated at the end of each block)
test is over if either countblocks = (parameter) maxTestBlocks
OR if remainingtasktime <= 0
countTrialsStarted Counts all trial sequences that got started by script
(though trial sequence might have been cut-off before any response could have been given)
countAttemptedTrials Counts all attempted trials (across test blocks)
countCompletedTrials Counts all trials (across test blocks) in which participants input a row number
countLateMatrix Counts how many times participant was late with selection response
countCorrect Counts all correct trials (across test blocks)
propCorrect Proportion correct responses out of all attempted test trials

Raw Data

File Name: visualscanning_raw*.iqdat

Data Fields

NameDescription
build Inquisit version number
computer.platform Device platform: win | mac |ios | android
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
blockCode Name of the current block
blockNum Number of the current block
trialCode Name of the current trial
trialNum Number of the current trial
phase "practice" vs. "test"
countBlocks Counts the number of test blocks started
stimulusItem Presented stimuli
response The participant's response
correct The correctness of the response
latency The response latency in ms
not all trials that are run might record data
In this script, by default the relevant raw data is saved by trial.savetrialdata.
Because trial.savetrialdata is the default trial to save the data for each trial sequence,
response/correct/latency are NOT storing any useful variables by default.
If you want to save data from each trial, go to section TRIALS and set
recorddata = true for each trial that should save data.
targetCode Contains the target box e.g. r16c3
correctrowDigits Stores the correct row digit of the current trial sequence
inputRowDigits Stores the complete row digit response (both digits)
responseCode Stores the response code
"correct"
"incorrect" (input was wrong)
"late matrix response" (participants took too long to press the spacebar)
"late row response" (participants pressed spacebar but then took too long to input the row number)
matrixRt Stores the latency of the Spacebar response in ms
firstDigitRt Stores the latency of the first digit input in ms
secondDigitRt Stores the latency of the second digit input in ms
countTrialsStarted Counts all trial sequences that got started by script
(though trial sequence might have been cut-off before any response could have been given)
countAttemptedTrials Counts all attempted trials (across blocks)
attempted: responsecode is set to four response options
countCompletedTrials Counts all trials (across blocks) in which participants input a row number
(responsecode is either correct or incorrect)
countLateMatrix Counts how many times participant was late with Spacebar response
countLaterowConfirmation Counts how many times participant was late with row number input
countCorrect Counts all correct trials (across blocks)
propCorrect Proportion correct responses out of all attempted ones
remainingTaskTime Stores how much time is left for another block (updated at the end of each block)
maxBlockDuration Stores the maximum block duration time that is still available for the current block (in ms)
blockStartTime Stores the elapsed time at the start of each new block in ms

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
responseKey The response key " " -> spacebar
fontSizeLetters Fontsize of the letters in screen height percentages 2.5%
fontSizeFixation Fontsize of the fixation mark in screen height percentages 3%
maxTestBlocks Maximum number of test blocks to be run (e.g. 2)
nrTrainingBlocks Number of training blocks to be run
Englund et al (1987) suggest to run 10 (p.43)
1
maxTaskTime Maximum duration of the task in ms 300000ms => 5min
showFeedback 1 = feedback is provided after 2nd digit row input
0 = no feedback is provided
( if responses were too late a beep is played in either condition)
fixationDuration Duration of the fixation trial in ms 500ms
matrixDuration Maximum duration of the matrix presentation in ms 10000ms => 10s
confirmationDuration Maximum duration allotted to input both digits of row number in ms
posttrialDuration Time allotted between input of second digit and next fixation cross in ms
this duration is used to present (optional) feedback and the beeps