target

Experiments

target is the primary/reference stimulus of a trial, presented separately from the test stimuli stim1..stimN. Use it for match-to-sample, priming, or memory designs where one reference item is shown above (or before) a row of test items. On image trials it is shown as an image; on word trials it is shown as HTML text. The target is never clickable: only the test stimuli are.

Syntax

Put the filename of the reference stimulus in the cell, WITHOUT its extension: sample_face. stimFormat supplies the extension (an image extension such as .jpg, .png, .gif, .bmp, .pdf, .jpeg or .webp), and the file must be uploaded to the project’s stimuli. The extension is not added a second time when the cell already ends with exactly that stimFormat value, and it is never added on stimFormat: list rows.

On word trials (stimFormat is word) the cell is free text instead. It is rendered as HTML, and variable placeholders are replaced before it is shown.

Leave the cell empty when a trial has no target. A value containing % is treated as a dynamic stimulus and resolved when the trial runs instead of being preloaded.

Options

Value	Trial type	Behavior
empty	any	No target
<basename>	image	Preloaded image with stimFormat appended as extension; shown centered horizontally above the stim row
<basename>.<ext>	image	Extension kept as-is if it matches stimFormat exactly
any text / HTML	word	Rendered as HTML text above the test stimuli
text with %	image	Treated as a dynamic stimulus, not preloaded

There are no comma/semicolon sub-options for target; the cell is used verbatim as a single stimulus.

Defaults & missing values

Leave the cell empty, or leave the column out, and the trial has no target: only the test stimuli are shown.

Any non-empty value gives the trial a target. A target counts as one extra stimulus when the trial is split across screens, and it takes the first screen. If no test stimuli end up sharing that screen, the target is shown on its own.

Works with

• stimFormat decides both the trial type and the extension appended to the target filename. An extension written into the target cell itself never affects the trial type.
• ISI and presTime (sequential presentation): with a target and a numeric ISI, the target takes the first screen. Shown on its own, it stays up for presTime and is then hidden before the remaining screens appear. If test stimuli share its screen, target and those stimuli appear together.
• Simultaneous presentation: the target is drawn horizontally centered above the row of test stimuli, at the image’s own size. stimSize and stimPos apply only to the test stimuli, never to the target.
• Audio and video trials: the target is NOT played. The playlist is built from the numbered stim slots only, so a value in target has no effect there.
• With a numeric ISI, no target and more than one image or word stimulus, stim1 goes on the first screen and the rest on the second.
• stimScreens (explicit screen grouping) is ignored on target trials: a target trial always uses the ISI-driven screen building. Combining a target with a stimScreens value is rejected when you save (“stimScreens cannot be combined with the target column”).

Examples

type	stimFormat	target	stim1	stim2	presTime	keyboard	key
test	.jpg	sample_face	face_a	face_b	2000

Shows stimuli/sample_face.jpg above face_a.jpg and face_b.jpg for 2000 ms; both test images are clickable (no keyboard/buttons).

type	stimFormat	target	stim1	stim2	presTime	ISI
test	.png	cue	probe1	probe2	500;1000	300

Sequential: cue.png alone for 500 ms, then (after a gap, see Tips & gotchas) probe1.png+probe2.png.

type	stimFormat	target	stim1	stim2	keyboard	key
test	word	<b>DOG</b>	cat	dog		stim2

Word trial: bold “DOG” as target text above the two clickable words. Note: a word click records the stim NUMBER as the response, so the correct answer must be given as stim2 (or 2), not as the word text.

Tips & gotchas

• A target counts as one extra stimulus when screens are computed, so a single ISI value with a target gives you a target screen plus one test screen.
• Word targets render HTML rather than escaping it, so markup such as <b>DOG</b> works and stray angle brackets are interpreted as tags.

Caution

Extension matching is case sensitive. Face1.JPG on a stimFormat: .jpg trial gets the extension appended again, giving Face1.JPG.jpg and a missing file. Keep filenames and stimFormat in the same case, or leave the extension off the cell entirely.

Caution

When the target is shown on its own, the gap before the next screen is NOT the ISI you set: it lasts as long as the target’s own presTime. Take that into account when you time lone-target trials.