Gaze Interaction States
Gaze Enter
Gaze Enter is the first and most basic state, triggered as soon as gaze enters an element.
Use this when you want something to happen immediately when the user looks at the element, for example to initiate visual feedback. However, keep in mind that if this state triggers visual or behavioral effects, it can cause the user experiencing a lack of control, also known as Midas Touch.
In Eye Tracking, activating elements unwillingly with gaze is referred to as Midas Touch.
This sensation is strongest when using Gaze Enter or short time thresholds for Dwell Activation to trigger events that make noticeable changes. Using Gaze with Explicit Activation gives control to the user and mitigates Midas Touch.
The higher the cost of error of an unwilling activation, the stronger is the Midas Touch effect and the more negative it will be perceived.
Gaze with Explicit Activation
Gaze combined with an explicit activation signal (e.g., button press) is the most predictable and controllable Gaze Interaction State.
Gaze with Explicit Activation is in most cases preferred over Gaze Enter or Dwell Activation for elements that have a high cost of error, such as picking up an object or activating a UI button because it gives more control to the user and mitigates accidental activation and Midas Touch.
Don’t use your eyes as an explicit activation signal, e.g. blinking or performing eye gestures. This easily becomes straining and difficult because it is not what we normally use our eyes for.
Gaze and the explicit activation signal are not necessarily happening at the same time. The user’s eyes might have moved away from the element they want to interact with, at the moment the explicit activation signal occurs. For example, if the user wants to click a UI button, they might look at it, and then start to press a button on the controller. Before this press occurs, the user have already moved their eyes elsewhere.
Usually, more than one Gaze Interaction State is used when creating real-world examples. A UI element like a button would consist of the two states:
- Gaze Enter to trigger initial visual feedback, telling the user that the element is gaze-aware.
- Gaze with Explicit Activation by pressing a button on the controller to activate the UI button.
Dwell Activation
Gaze for a specified time threshold triggers the state Dwell Activation.
Dwell Activation is not as predictable and controllable as Gaze with Explicit Activation, but can be useful in certain situations. Use this when you want continued lingering gaze to cause an activation. For example, having NPCs react to the user’s gaze can feel unnatural if they react immediately, rather have them react and turn their head towards the user after the user has looked at the NPC for a little while.
Using large thresholds for Dwell Activation, e.g., forcing the user to focus for a longer period of time before triggering an event, can feel straining and unnatural.