fixationStim

Experiments

Caution

Legacy column. It still works in old experiments, but do not use it in new ones. Use fixation instead.

Caution

Legacy column. It still works in old experiments, but do not use it in new ones. Use fixation instead.

Legacy switch that shows the built-in fixation cross while the stimuli are on screen. Its only effect is the same as adding the withStim keyword to the fixation column’s value; the cell’s actual content is otherwise ignored. It does NOT define a custom fixation stimulus: the cross is always the standard + glyph. New trial files should put withStim in the fixation column instead.

Syntax

Put any non-empty value (for example 1) in the cell to show the built-in + cross while the stimuli are on screen.

Every non-empty value behaves identically; the cell’s content itself is never displayed. Leave the cell empty for no cross.

Options

Value	Effect
empty	No effect.
anything else (1, +, x, dot.png…)	Equivalent to appending ;withStim to the fixation column: cross shown during each stimulus screen, hidden after the last stimulus screen’s presTime. The value itself (filename, glyph, number) is never rendered.

Defaults & missing values

• When the column is absent or the cell is left empty, the column has no effect.
• With a value here and an empty fixation cell, the trial behaves as if fixation were withStim.
• With a value here and a filled fixation cell, withStim is added to that cell’s keywords. The legacy fixation value 1 still means ITI, so 1 there plus any value here behaves as ITI;withStim.

Works with

• fixation: this column simply adds withStim there. If fixation contains allTrial or allStim, the added withStim is ignored, making fixationStim redundant on those trials.
• Cross appearance: size comes only from a numeric token in fixation, color from the color/textColor column’s fixation:<color> option. fixationStim cannot change either.
• Audio/video trials: the cross is always hidden when playback starts, so fixationStim has no visible effect on audio/video stimuli.
• type = instructions: instruction screens never show a cross.

Examples

1. Cross overlaid on the stimuli only:

type	stimFormat	stim1	presTime	fixationStim
test	.png	face	1500	1

Equivalent to fixation = withStim: cross visible for the 1500 ms the image is up, hidden afterwards.

2. Combined with an ITI fixation:

type	stimFormat	stim1	presTime	ITI	fixation	fixationStim
test	word	word_one	1000	500	ITI	1

Computed value ITI;withStim: cross during the 500 ms ITI and while word_one is displayed.

3. Value content is ignored:

type	stimFormat	stim1	presTime	fixationStim
test	.jpg	scene	2000	dot.png

Shows the standard + cross with the stimulus. dot.png is never loaded or displayed.

Tips & gotchas

Note

Despite its name, this column cannot define a custom fixation stimulus. Any non-empty value simply turns on the standard + cross during the stimuli; the value itself is never shown.

• A whitespace-only cell counts as set; the value is not trimmed.
• With withStim active and no ISI keyword in fixation, the cross also stays visible during the ISIs between screens.
• The cross is hidden after the last stimulus screen’s presTime only when that presTime is non-zero. With a presTime of 0 the cross stays until the trial ends (see the fixation page).