Image Sequence Stimuli

Version: v1 (current)

Display multiple images one after another in a fixed or randomized order, with optional auto-advance timing.

Overview

The Image Sequence stimuli task shows multiple images one at a time in succession. It supports both self-paced advancement (click Next) and automatic timed advancement. This task is useful for rapid serial visual presentation (RSVP), sequential memory encoding, and any paradigm requiring ordered image presentation.

Common research uses include:

RSVP paradigm: Rapid image streams for attentional research
Attentional blink: Image-based attentional blink studies
Sequential memory: Remember image order or specific items
Dynamic scene perception: Show scene changes over time

Where to Configure

In the study editor, add a new task and choose Stimuli → Image sequence. Or add a base "Stimuli" task and set Type to "Images (sequence)".

Setup Steps

Click Upload images and select one or more images.
After at least one image is uploaded, a hint appears above the list reminding you that you can drag to reorder.
Arrange order by dragging items in the list. The first item shows first.
To remove an image, click the x on its row.
Optional: enable Randomize sequence order to shuffle the list for each participation session.
Optional: enable Auto-advance and set "Advance after (seconds)". Even with auto-advance, the participant can still click Next to proceed.
Click Save.

Configuration Parameters

Sequence-Specific Parameters

Parameter	Type	Default	Description
Images	file upload	-	Upload one or more images to display in sequence
Randomize Sequence Order	boolean	false	Shuffle the image order for each participant session
Auto Advance	boolean	false	Automatically advance to the next image after a set duration
Advance After (seconds)	number	-	Seconds to display each image before auto-advancing

Common Stimuli Parameters

Parameter	Type	Default	Description
Button Text	string	'Continue'	Text for advancement button
Background Color (hex)	string	'FFFFFF'	Background color

Participant Flow

The participant sees one image at a time, centered on the page.
Clicking Next moves to the next image. On the last image, Next finishes the task.
If Auto-advance is enabled, images also advance automatically after the specified number of seconds.
If Randomize sequence order is enabled, the image order is shuffled when the session starts and stays fixed for that participant.

Design Recommendations

Image quality: Use high-contrast images sized for screens; the app scales images to fit without cropping.
Order: Keep the order simple and communicate expectations in the task instructions if needed.
Encoding studies: Use fixed auto-advance durations (e.g., 2 s per image) for consistency.
RSVP: For rapid presentation, use very short advance times (200-500 ms per image).
Practice stimuli: Use different images for practice than for the main task.
Counterbalancing: Enable randomization to counterbalance order effects across participants.

Common Issues and Solutions

Issue	Solution
Images don't load	Use absolute URLs; check CORS settings; test on the target browser
Participants skip too quickly	Use Auto-advance with a fixed duration; disable manual advancement if needed
Inconsistent display durations	Use Auto-advance for precise timing control
Image order matters but is randomized	Disable Randomize sequence order; arrange images manually in the editor

Data Output

Markers and Responses

The task records high-resolution timestamps in the markers collection. No response object is recorded (participants advance by clicking Next or via auto-advance).

Markers (sequence_order):

{
  "type": "sequence_order",
  "ts": "2024-01-01T00:00:01.000Z",
  "hr": 1234.56,
  "data": {
    "order": ["image_a.jpg", "image_c.jpg", "image_b.jpg"],
    "randomized": true
  }
}

Markers (stimulus_shown):

{
  "type": "stimulus_shown",
  "ts": "2024-01-01T00:00:01.100Z",
  "hr": 1334.56,
  "data": {
    "index": 0,
    "filename": "image_a.jpg",
    "url": "https://example.com/images/image_a.jpg"
  }
}

Markers (manual_next) -- when participant clicks Next:

{
  "type": "manual_next",
  "ts": "2024-01-01T00:00:03.500Z",
  "hr": 3734.56,
  "data": {
    "index": 0
  }
}

Markers (autoadvance_next) -- when auto-advance timer fires:

{
  "type": "autoadvance_next",
  "ts": "2024-01-01T00:00:03.000Z",
  "hr": 3234.56,
  "data": {
    "index": 0,
    "scheduled_offset_ms": 2000,
    "drift_ms": 3
  }
}

Summary Artifact

None. The image sequence stimulus task does not generate a summary artifact.

References

Bradley, M. M., & Lang, P. J. (2007). The International Affective Picture System (IAPS) in the study of emotion and attention. In J. A. Coan & J. J. B. Allen (Eds.), Handbook of Emotion Elicitation and Assessment (pp. 29-46). Oxford University Press.

Overview​

Where to Configure​

Setup Steps​

Configuration Parameters​

Sequence-Specific Parameters​

Common Stimuli Parameters​

Participant Flow​

Design Recommendations​

Common Issues and Solutions​

Data Output​

Markers and Responses​

Summary Artifact​

References​

See Also​