Demand Selection Task

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

Millisecond thanks Dr. Malte Friese for collaborating on this script!

Created: January 11, 2016

Last Modified: January 05, 2023 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements the Demand Selection Task based on:

Kool W, McGuire JT, Rosen ZB, Botvinick MM (2010) Decision making and the avoidance of cognitive demand. J Exp Psychol Gen 139: 665–682.

McGuire JT, Botvinick MM (2010) Prefrontal cortex, cognitive control, and the registration of decision costs. Proc Natl Acad Sci U S A 107: 7922–7926.

The implemented version in this script is based on Kool et al (2010), Experiment 3. The script automatically adapts response keys to the dominant hand. (dominant hand on mouse, other hand on response buttons)

Duration

50 minutes

Description

Participants see 2 stimuli (patterned discs) on the screen and are asked to select one of them with the mouse. A digit appears on the selected disc. The color of the digit represents a different cognitive task: blue ('parity' task)-> decide if number is even (if so press the right response key; otherwise press the left response key) purple ('magnitude' task)-> decide if number is bigger than 5 (if so press the right response key, otherwise press the left response key).

One of the 2 discs represents a high cognitive demand condition: if chosen, the cognitive tasks (parity/magnitude) repeatedly switch from one to the other. The other disc represents a low cognitive demand condition: if chosen, the cognitive tasks (parity/magnitude) repeat the previous ones with a high likelihood

Procedure

Practice Block(s):
• 10 trials: random order of 5 parity and 5 magnitude tests (digits are randomly chosen)
• repeats if block performance < 90%

Test Block set-up:
• 8 blocks (75 trials each = 600 trials total) with 8 different stim pairs (stims randomly assigned to each run; no repeats)
• one stim is randomly assigned the 'high cognitive demand' condition; the other stim is assigned the 'low cognitive demand' condition
• 8 different spatial arrangements of stim pairs (circular arrangement, stims are opposite of each other and wander in 45degrees increments);
randomly sampled (without replacement) for each block

Trial Sequence:
Select center with mouse -> stims appear: select one of the stims -> digit appears on selected stim in either blue or purple: do task

2 cognitive tasks:
a) digit in color purple: 'if digit is even, press right key, otherwise left key (both with left hand)
b) digit in color blue: 'if digit > 5, press right key, otherwise left key (both with left hand)

=> 8 digits are used: 1, 2, 3, 4, 6, 7, 8, 9; equally often sampled across 600 trials (= each sampled 75 times)

2 cognitive demand conditions:
a) low cognitive demand: same cognitive task as previous trial with probability = 0.9
b) high cognitive demand: same cognitive task as previous trial with probability = 0.1

the first trial in each block is randomly chosen to be a magnitude or parity task.
It's switch category is set to "first trial" (thus it's neither a switch nor a reversal trial)

Stimuli

provided by Millisecond (stimuli are not original to Kool et al, 2010)
They can be edited under section Editable Stimuli

Instructions

provided by Millisecond (instructions are not original to Kool et al, 2010)
They are provided and presented in the form of html-files which can be edited directly.

Summary Data

File Name: demandselectiontask_summary*.iqdat

Data Fields

Raw Data

File Name: demandselectiontask_raw*.iqdat

Data Fields

Parameters

The procedure can be adjusted by setting the following parameters.