Measuring Mental Effort in Real Time Using Pupillometry

Area of Science:

• Cognitive Science
• Neuroscience
• Human-Computer Interaction

Background:

• Mental effort is crucial for task performance but challenging to measure.
• Pupil diameter is a reliable real-time indicator of mental effort.
• Existing pupillometric methods may lack sensitivity or real-time applicability.

Purpose of the Study:

• Introduce RIPA2, an enhanced pupillometric index for real-time mental effort assessment.
• Validate RIPA2's sensitivity and consistency against established measures and tasks.
• Demonstrate RIPA2's utility in diverse cognitive load scenarios.

Main Methods:

• Developed RIPA2 by refining Savitzky-Golay filter parameters for pupil diameter analysis.
• Validated RIPA2 using an N-back memory task and a naturalistic information search task.
• Compared RIPA2 performance with the original RIPA method and offline cognitive load indices like LHIPA.

Main Results:

• RIPA2 reliably tracked mental effort variations across different tasks.
• RIPA2 showed improved sensitivity and consistency over the original RIPA.
• RIPA2 aligned well with offline measures and captured effort differences in N-back and information search tasks.

Conclusions:

• RIPA2 offers a robust, continuous, low-latency method for assessing mental effort.
• RIPA2 has potential applications in education, medicine, workplaces, and adaptive interfaces.
• This index facilitates objective mental effort monitoring beyond laboratory settings.