How to Choose Eye Tracking Calibration Settings

Before running a webcam eye tracking study in Labvanced, a handful of calibration decisions determine both the accuracy of your gaze data and how long calibration takes for each participant. All of these settings live under Settings tab → Physiology → Eye-Tracking.

Physiology Toolbox Version

The Physiology Toolbox Version (Settings tab → Physiology → Common Settings → Physiology Toolbox Version) controls which version of Labvanced's eye tracking engine your study uses. For calibration purposes, use the current default unless you are continuing an existing study built on an older version: the current default supports Fixation Detection mode in the task editor, which older versions do not.

Calibration Length

Calibration Length (Settings tab → Physiology → Eye-Tracking → Calibration Length) is the single biggest trade-off in eye tracking calibration: more calibration points produce more accurate gaze predictions, at the cost of a longer calibration for participants. Three options are available to researchers building a new study:

130 points, 9 poses (~5 minutes): accuracy of approximately 1.5 visual degrees
55 points, 4 poses (~2 minutes): accuracy of approximately 2.0 visual degrees
15 points, 1 pose (~30 seconds): accuracy of approximately 2.7 visual degrees

A fourth, longer option (175 points, 12 poses, ~7 minutes) exists in Labvanced's underlying settings but is not available to researchers building a new study through the standard interface.

How to choose: if your study depends on distinguishing between closely spaced targets (for example, reading research or small on-screen elements), the 130-point option's higher accuracy is worth the extra calibration time. If your study only needs to distinguish between a few widely separated regions of the screen, the 55-point or 15-point option keeps the study shorter without meaningfully affecting your results. Studies with children or participants who may struggle to sit through a longer calibration often favor the shorter options for this reason.

Calibration Quality Control

Two settings let you enforce a minimum calibration quality rather than accepting whatever the initial calibration produces:

Set Maximum Calibration Error, when enabled, reveals Max Calibration Error (%), the maximum calibration error allowed as a percentage of the screen diagonal. Lowering this value improves data quality but means more participants will fail calibration outright.
Max Nr Calibration Attempts controls how many times a participant may retry calibration before the study fails completely.

Tightening both of these makes sense for studies where data quality matters more than sample size (precise timing or spatial measurements). Studies prioritizing sample size, or piloting a new task, generally leave these at their defaults.

Calibration Image and Engagement Options

Calibration Image Type lets you choose between dots and animal icons for the calibration targets.
Play Calibration Sounds, when enabled, reveals a volume slider (available from v1.0 and above) to adjust the calibration sound's loudness.
Show Grid displays a grid during calibration, which can help participants anticipate where the next calibration point will appear.
Allow Calibration Reuse lets a participant skip calibration entirely if they already calibrated on the same device within the last few hours. This is particularly useful while developing and testing a task yourself, since it avoids re-running calibration on every test run.

Infant Friendly Mode

Infant Friendly Mode (Settings tab → Physiology → Eye-Tracking → Infant Friendly Mode) automatically adjusts the calibration settings above toward values more suitable for infant participants (typically animal icons, sounds enabled, and a shorter calibration length) when toggled on. You can still edit any of the adjusted values afterward.

Virtual Chinrest and Chinrest Constraint

During calibration, a participant's head position is recorded as a center pose, referred to as the virtual chinrest. Virtual Chinrest (Settings tab → Physiology → Eye-Tracking → Virtual Chinrest) controls when this position is enforced during the rest of the study:

Enable (check during trials): enforced continuously; the study pauses immediately if the participant moves away from the center pose
Enable (check between trials): enforced only between trials, not during them
Enable (check between trials) and show ignore button: same as above, but with an option for the participant to dismiss the prompt and continue
Disable: not enforced at all

A related setting, Chinrest Constraint, controls how much movement is tolerated before the chinrest is considered violated, ranging from very loose to very strict. Stricter settings improve accuracy but are harder for participants, especially children, to maintain. A common pattern is to pair a loose constraint with the ignore-button mode for infant studies, and a stricter constraint with continuous enforcement for adult studies where precision matters most.

Minimum Facemesh Speed

Minimum Facemesh Speed (Settings tab → Physiology → Eye-Tracking → Minimum Facemesh Speed) sets a threshold for how many face snapshots per second a participant's device camera must be able to process to take part in the study, ranging from Very Low (0.5Hz) to Very High (15Hz). This is a data-quality floor: lower thresholds admit more participants' devices but degrade data quality, while higher thresholds restrict participation to faster devices. A medium setting (Medium Low (5Hz) to Medium (7.5Hz)) is a reasonable default for most studies.

What Participants Actually See

The settings on this page determine what the calibration process looks and feels like from the participant's side, but not the exact sequence of prompts. For that, see The Participant Calibration Experience.

Frequently Asked Questions

Which Calibration Length should I use for my study?

It depends on how closely spaced your on-screen targets are. If your study depends on distinguishing closely spaced targets, the `130 points, 9 poses` option's higher accuracy is worth the extra time. If your study only needs to distinguish a few widely separated regions, `55 points, 4 poses` or `15 points, 1 pose` keeps the study shorter without meaningfully affecting results.

What happens if a participant fails calibration too many times?

The study fails for that participant once they exceed `Max Nr Calibration Attempts`. Combined with `Set Maximum Calibration Error`, this lets you enforce a data-quality floor instead of accepting whatever the initial calibration produces.

Can I make calibration easier for infant or child participants?

Yes. `Infant Friendly Mode` automatically adjusts calibration toward values more suitable for infants, typically animal icons, sounds enabled, and a shorter calibration length, and any of the adjusted values can still be edited afterward.

Do I need to upgrade my study's Physiology Toolbox Version just to use calibration?

No. Calibration itself works on older versions. The current default version is only necessary if you also need Fixation Detection mode in the task editor, which older versions do not support.

Can returning participants skip calibration on a second session?

Yes, if `Allow Calibration Reuse` is enabled and the participant returns on the same device within a few hours of their previous calibration. This is also useful while developing and testing a task yourself.