Behind Eyetracking: How the Brain Utilizes

Its Eyes

Dixon Cleveland LC Technologies, Inc.

Visual Pathways

Eye Cross Section

Eyes are Excellent PointersCone Density

Rod Density

Foveola1.2 deg~100 conesacross

Optic AxisVisual Axis

Eye Anatom y

Rod and Cone Density

Cone Density

Macular Region

Ocular Muscles

Fixations and Saccades

Visual Pathways in the Brain

• Perhaps the most important reason eyetracking will play an ever more crucial role in UX is that our eye activity is driven by our brains. The old cliché that our eyes provide a window to our minds is well substantiated physiologically and cognitively. By providing insights to brain activity, monitoring eye activity has significant potential to help programs interact with people in more naturally human ways – both in general program design and in on-line human interaction.

• This discussion summarizes the physiological and cognitive processes underlying the brain’s control of the eyes, which provides the foundation for using eyetracking in UX.

• Old cliché: Eyes are window to the brain• Main cognitive input to the brain is the eyes• It is the main channel through which we perceive the

outside world• Eyes can only look one place at a time• We have to move our eyes around to get targeted

information• Our brains drive our eyes• It’s a continuous feedback loop• It happens 4 times per second

Gazepoint Calculation Model

GazeLine

GazePoint

GazeVector

EyeLocation