Simply EEGLAB

STUDY designs and variables

Station 8 · Lesson 4 · EEGLAB 2026.1

In the GUI

StudySelect/Edit study design(s)Edit STUDY design -- pop_studydesign()
Design name STUDY.design 1
Edit the independent variables for this design Categorical variable: condition - Values (animal - distractor)Categorical variable: group - Values (F - M)
New Design 2
RenameStudy design name:Ok image x gender
NewAdd variable
Select independent variableSelect variable valuesOk conditionanimaldistractor
NewOk groupFM
NewRename image only
Design nameOk image x gender
Re-save STUDY file (if saved previously) animal_mine.study
Ok Selecting STUDY design 2Resaving STUDY

Script

STUDY = std_makedesign(STUDY, ALLEEG, 2, 'name', 'image x gender', ...
    'variable1', 'condition', 'values1', {'animal', 'distractor'}, 'vartype1', 'categorical', ...
    'variable2', 'group', 'values2', {'F', 'M'}, 'vartype2', 'categorical');
STUDY = std_makedesign(STUDY, ALLEEG, 3, 'name', 'image only', ...
    'variable1', 'condition', 'values1', {'animal', 'distractor'}, 'vartype1', 'categorical', ...
    'variable2', 'none');
STUDY = std_selectdesign(STUDY, ALLEEG, 2);
STUDY = pop_savestudy(STUDY, ALLEEG, 'savemode', 'resave');
for k = 1:numel(STUDY.design)
    d = STUDY.design(k);
    fprintf('Design %d: %s\n', k, d.name);
    for v = 1:numel(d.variable)
        if ~isempty(d.variable(v).label)
            fprintf('   %-10s paired: %-4s values: %s\n', d.variable(v).label, ...
                d.variable(v).pairing, strjoin(d.variable(v).value, ' '));
        end
    end
end
fprintf('Current design: %d\n', STUDY.currentdesign);
eeglab redraw;

Which value should I choose?

	Within subjects	Between subjects
Meaning	Each participant has every value	Each participant has one value
In D6	Picture type: animal and distractor	Gender: F and M
Usually stored in	condition	group
Test	paired: compares each participant with themselves, removing differences between people	unpaired: compares two groups of different people
Statistical power	Higher for the same number	Lower, and needs more participants
Your question	Design	Why
Does the ERP differ between animal pictures and the others?	3, `image only`	A direct paired test on 14 participants, and a plot with two curves instead of four. The 2×2 design also computes the main effect of picture, but it is harder to read.
Does the picture effect differ between women and men?	2, `image x gender`	The interaction between the two variables needs both in one design.
Does the ERP differ between women and men?	A design with group only	unpaired, 7 against 7.

For your Methods

A 2 × 2 mixed design was defined in the STUDY, with image category (animal, distractor) as a within-subject factor and gender ([7] female, [7] male) as a between-subject factor (std_makedesign, EEGLAB 2026.1).

In the GUI

Script

Which value should I choose?

For your Methods

More