Flexiforce Sensors
One data point I would like to gather on pilot affect/performance is the amount of force applied by the pilot to control during flight. This would involve measuring how the pilot grip strength on controls such as a joystick or air brake handle varies over time, or how hard the pilot pushes on rudder pedals.
A likely candidate for these measurements are piezoresistive Flexiforce sensors from Tekscan, a spin-off of research by the MIT media lab in Affective Computing. These are this, flexible circuits that change resistance based on the amount of force applied to them.