Garner Interference Task

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

Created: January 05, 2013

Last Modified: January 15, 2023 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a Garner Interference Paradigm that systematically varies the dimensions of irrelevant information to study interference on the processing of relevant information. Ridderinkhof et al (1997) used this paradigm to study the development of attention in children.

The implemented task is based on:

Ridderinkhof, K. R., van der Molen, M. W., Band, P. H., & Bashore, T. R. (1997). Sources of interference from irrelevant information: A developmental study. Journal of Experimental Child Psychology, 65, 315–341.(Experiment1)

Duration

30 minutes

Description

The two main dimensions used in this paradigm are tilt and color. Sometimes participants have to respond to the tilt of a line, in other cases they respond to the color, either of a surrounding box (in which case color and tilt are SEPARATED dimensions) or the color of the line itself (in which case color and tilt are INTEGRATED dimensions => more interference predicted). In addition, the change in color and tilt is systematically varied. The change can be: a) correlated (either the dimensions would require the same response=congruent OR they would require opposite responses=incongruent) b) orthogonal (= independent of each other => absence of a correlation) c) neutral (= change happens only in one dimension but never in the other).

In each trial, participants view a box in the middle of the screen. Inside the box is a line that can be tilted to the left or right. The color of the box or the color of the line itself can change from red to blue.

Participants are instructed to pay attention to only one dimension (=relevant dimension) a) the tilt of the line OR b) the color of either the box (separated condition) or the line itself (integrated condition) and ignore changes in the other (irrelevant) dimension as best as they can.

The actual task they have to do is a simple categorization task: if the line tilts to the right, press a certain key. If the line tilts to the left, press another key. Same for the color tasks.

Procedure

2 Dimensions (Color vs. Tilt), blocked-format x
2 Dimensional Configurations (integrated vs. separated), blocked-format x
3 Variation Types (control, correlated, orthogonal), blocked-format

(A) Color vs. Tilt: color changes (red <-> blue) vs. changes in the tilt of the line (left <-> right)
if relevant dimension is color: the color of the unattended configuration (line or box) is yellow
if relevant dimension is tilt and no color changes should occur at all (control condition): box and line are purple
(red+blue -> purple)

(B) Integrated vs. Separated: color changes of the line itself vs. color changes of the box surrounding the line

(C) Control vs. correlated vs. orthogonal:
Control: only changes in the relevant dimension occur; the irrelevant dimension is held constant
Correlated: changes in the relevant dimension are tied to (dependent on) changes in the irrelevant dimension
2 possible matches:
congruent -> both changes require the same response or
incongruent -> both changes require opposite responses
Orthogonal: changes in the relevant dimension are independent of changes in the irrelevant dimension
(half of the combinations are congruent vs. half are incongruent)

=> 16 different block types, tested all within-subjects

EXPERIMENTAL SET-UP
(a) 4 practice blocks (with error feedback)
(b) 12 experimental blocks: each block consisted of 24 trials; left/right responses occur equally often (no feedback)
you can easily reduce the number of trials run per block (see Editable Parameters)
(c) A rest block in between each block


1. The number of trials run per block can easily be reduced (see Editable Parameters)
2. To run a reduced number of blocks, change the blocks called by the 'expt' elements under section EXPERIMENT

RESPONSE KEYS/STIMULI:
Use of response keys (default: Y and B keys) is counterbalanced across participants. Assignment is done by groupnumber to
any of the 4 possible key combination conditions.

EVEN groupnumbers align the tilt with the location of the left and right response buttons.
ODD groupnumbers use the opposite location.

! The location of the (default) response keys (right "L" or left "A" on the keyboard) could introduce the potentially
unwanted variable "compatibility with tilt direction".
To avoid, use
(a) different response keys (change under Editable Parameters, e.g. Y and B)
(b) different stimuli: A set of possible alternative stimuli is provided under section Editable Stimuli -> item.lines
The set of alternative stimuli are Vs that differ in whether they are upside down or rightside up (replacing the direction
of left vs right). The composite stimulus for the color control condition is a diamond as it contains both V directions.

Instructions

can be edited under section Editable Instructions

Summary Data

File Name: garnerinterferencetask_summary*.iqdat

Data Fields

Raw Data

File Name: garnerinterferencetask_raw*.iqdat

Data Fields

Parameters

The procedure can be adjusted by setting the following parameters.