Keep Track Task

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

Created: January 07, 2017

Last Modified: January 27, 2023 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a 'Keep Track Task'; a test of executive functioning focusing on continuously updating working memory representations.

The implemented procedure is similar to the one outlined by:

Friedman, N.P., Miyake, A., Young, S.E., DeFries, J.C., Corley, R.P., & Hewitt, J.K. (2008). Individual Differences in Executive Functions Are Almost Entirely Genetic in Origin. Journal of Experimental Psychology: General, 137, 201-225.

The Friedman et al (2008) task is in turn based on: Yntema, D. B. (1963). Keeping track of several things at once. Human Factors, 5, 7–17.

Duration

15 minutes

Description

Participants need to mentally update the state of key categories while watching a sequence of 15 words that belong to 6 different categories. Before the presentation, participants are told the specific categories to keep track of and these target categories are displayed on screen throughout the presentation. The number of target categories to keep track of (of the 6 possible) varies from round to round (default in this script: 2-4). At the end of each round, participants are asked to enter the last item presented for each of the target categories.

Procedure

1. Practice Session
• by default, the practice session runs 3 rounds with difficulty level increasing from 2-4
=> number of rounds as well as their difficulty level can be adjusted by editing list.difficulty_practice
under section Editable Lists
• per round:
• target categories are sampled randomly for each round (no balancing across rounds)
• each category is presented at least twice and at most three times within the 15 word presentations
(it's randomly determined for each round which category is represented three times - no balancing across rounds);
order of category presentation is randomized
• the particular exemplars presented for each category are sampled at random from the 6 provided options
(constraint: no repeats within the same round)
• after recall, participants receive detailed feedback of their responses
• by default, practice session can be repeated if no more than parameters.maxNumberOfPracticeSessions (default: 2) have been run yet
(change settings under section Editable Parameters)


2. Test Session
• by default, the test session runs 12 rounds with difficulty levels 2, 3, 4 (each difficulty level is repeated 4 times,
levels are randomly selected)
=> Total words that need to be recalled: 2x4 + 3x4 + 4x4 = 36
=> number of rounds as well as their difficulty levels can be adjusted by editing list.difficulty_test
under section Editable Lists
• per round:
• target categories are sampled randomly for each round (no balancing across rounds)
• each category is presented at least twice and at most three times within the 15 word presentations
(it's randomly determined for each round which category is represented three times - no balancing across rounds);
order of category presentation is randomized
• the particular exemplars presented for each category are sampled at random from the 6 provided options (see Editable Stimuli)
(constraint: no repeats within the same round)
• after recall, participants receive detailed feedback of their responses by default. However, feedback can easily be
turned off by setting parameters.skipTestFeedback to 'true' (default setting is 'false', see section Editable Parameters)

Note on Accuracy Checks of entered Responses:
1) all entered responses as well as target items (e.g. India) are converted to lower-case letters for comparisons
Example: presented item: India; entered item: india (evaluated as correct)
Example: presented item: bear; entered item: BEAR (evaluated as correct)
2) empty characters are removed from all entered responses before comparisons
Example: presented item: 'brother'; entered item 'brother ' (evaluated as correct)
Example: presented item: 'gold'; entered item ' g o ld ' (evaluated as correct)

Trial/Round Sequence (default settings):

presentation of target categories until spacebar is hit -> 500ms delay ->
word presentation 1 (1500ms) -> isi (0ms) -> word presentation 2 (1500ms) -> etc. ->
word presentation 15 (1500ms) -> isi (0ms) -> recall delay (0ms) ->
recall until 'submit' button is pressed -> iti (default: 1000ms)


this script provides the code to run any difficulty level btw. 1-6.
To change the number of rounds run and/or the levels of difficulty levels run, simply
change list.difficulty_practice and/or list.difficulty_test under section Editable Lists

Stimuli

categories: Friedman et al (2008)
exemplars: provided by Millisecond

By default, this script runs with 6 exemplars per category. That reduces the chance to guess
the correct exemplar (per category) at the end of each trial to p ~ 0.17.

specific categories as well as exemplars can be edited under section "Editable Stimuli"

Instructions

provided by Millisecond - can be edited under section Editable Instructions

Summary Data

File Name: keeptracktask_summary*.iqdat

Data Fields

Raw Data

File Name: keeptracktask_raw*.iqdat

Data Fields

Parameters

The procedure can be adjusted by setting the following parameters.