Complex sentence: User experiences are recorded along with any comments they may have and, when smartphone cameras are activated, record facial expressions of the subjects, who are each paid approximately $10 to record a 20-minute experiential video description.
Split into simpler sentences: User experiences are recorded along with any comments they may have. When smartphone cameras are activated, they record facial expressions of the test subjects, who are each paid approximately $10 to record a 20-minute experiential video description.